csso - npm Package Compare versions

Comparing version 1.8.1 to 2.0.0

HISTORY.md

@@ -0,1 +1,20 @@
+## 2.0.0 (April 5, 2016)
+
+- No more `gonzales` AST format and related code
+- `minify()` and `minifyBlock()` is always return an object as result now (i.e. `{ css: String, map: SourceMapGenerator or null }`)
+- `parse()`
+    - Returns AST in new format (so called `internal`)
+    - Dynamic scanner implemented
+    - New AST format + dynamic scanner = performance boost and less memory consumption
+    - No more `context` argument, context should be specified via `options`
+    - Supported contexts now: `stylesheet`, `atrule`, `atruleExpression`, `ruleset`, `selector`, `simpleSelector`, `block`, `declaration` and `value` 
+    - Drop `needPositions` option, `positions` option should be used instead
+    - Drop `needInfo` option, `info` object is attaching to nodes when some information is requested by `options`
+    - `options` should be an object, otherwise it treats as empty object
+- `compress()`
+    - No more AST converting (performance boost and less memory consumption)
+    - Drop `outputAst` option
+    - Returns an object as result instead of AST (i.e. `{ ast: Object }`)
+- Drop methods: `justDoIt()`, `stringify()`, `cleanInfo()`
+
 ## 1.8.1 (March 30, 2016)
@@ -2,0 +21,0 @@

lib/compressor/clean/index.js

@@ -1,2 +0,2 @@
-var walk = require('../ast/walk.js').all;
+var walk = require('../../utils/walk.js').all;
 var handlers = {
@@ -7,3 +7,4 @@ Space: require('./Space.js'),
     Declaration: require('./Declaration.js'),
-    Identifier: require('./Identifier.js')
+    Identifier: require('./Identifier.js'),
+    Comment: require('./Comment.js')
 };
@@ -10,0 +11,0 @@

lib/compressor/compress/Atrule.js

@@ -1,2 +0,2 @@
-var resolveKeyword = require('../ast/names.js').keyword;
+var resolveKeyword = require('../../utils/names.js').keyword;
 var compressKeyframes = require('./atrule/keyframes.js');
@@ -3,0 +3,0 @@

lib/compressor/compress/index.js

@@ -1,2 +0,2 @@
-var walk = require('../ast/walk.js').all;
+var walk = require('../../utils/walk.js').all;
 var handlers = {
@@ -3,0 +3,0 @@ Atrule: require('./Atrule.js'),

lib/compressor/compress/Value.js

@@ -1,2 +0,2 @@
-var resolveName = require('../ast/names.js').property;
+var resolveName = require('../../utils/names.js').property;
 var handlers = {
@@ -3,0 +3,0 @@ 'font': require('./property/font.js'),

lib/compressor/index.js

 var List = require('../utils/list');
 var usageUtils = require('./usage');
-var convertToInternal = require('./ast/gonzalesToInternal');
-var convertToGonzales = require('./ast/internalToGonzales');
 var clean = require('./clean');
 var compress = require('./compress');
 var restructureBlock = require('./restructure');
+var walkRules = require('../utils/walk').rules;
 
-function injectInfo(token) {
-    for (var i = token.length - 1; i > -1; i--) {
-        var child = token[i];
-
-        if (Array.isArray(child)) {
-            injectInfo(child);
-            child.unshift({});
-        }
-    }
-}
-
-function readBlock(stylesheet, offset) {
-    var buffer = [];
+function readBlock(stylesheet) {
+    var buffer = new List();
     var nonSpaceTokenInBuffer = false;
     var protectedComment;
 
-    for (var i = offset; i < stylesheet.length; i++) {
-        var token = stylesheet[i];
-
-        if (token[1] === 'comment' &&
-            token[2].charAt(0) === '!') {
+    stylesheet.rules.nextUntil(stylesheet.rules.head, function(node, item, list) {
+        if (node.type === 'Comment' && node.value.charAt(0) === '!') {
             if (nonSpaceTokenInBuffer || protectedComment) {
-                break;
+                return true;
             }
 
-            protectedComment = token;
-            continue;
+            list.remove(item);
+            protectedComment = node;
+            return;
         }
 
-        if (token[1] !== 's') {
+        if (node.type !== 'Space') {
             nonSpaceTokenInBuffer = true;
         }
 
-        buffer.push(token);
-    }
+        buffer.insert(list.remove(item));
+    });
 
     return {
         comment: protectedComment,
-        stylesheet: [{}, 'stylesheet'].concat(buffer),
-        offset: i
+        stylesheet: {
+            type: 'StyleSheet',
+            rules: buffer
+        }
     };
@@ -55,16 +43,20 @@ }
 
-    var internalAst = convertToInternal(ast);
-    logger('convertToInternal', internalAst);
+    var seed = 1;
+    ast.firstAtrulesAllowed = ast.firstAtrulesAllowed;
+    walkRules(ast, function() {
+        if (!this.stylesheet.id) {
+            this.stylesheet.id = seed++;
+        }
+    });
+    logger('init', ast);
 
-    internalAst.firstAtrulesAllowed = ast.firstAtrulesAllowed;
-
     // remove redundant
-    clean(internalAst, usageData);
-    logger('clean', internalAst);
+    clean(ast, usageData);
+    logger('clean', ast);
 
     // compress nodes
-    compress(internalAst, usageData);
-    logger('compress', internalAst);
+    compress(ast, usageData);
+    logger('compress', ast);
 
-    return internalAst;
+    return ast;
 }
@@ -74,2 +66,3 @@
     options = options || {};
+    ast = ast || { type: 'StyleSheet', rules: new List() };
 
@@ -82,3 +75,3 @@ var logger = typeof options.logger === 'function' ? options.logger : Function();
     var result = new List();
-    var block = { offset: 2 };
+    var block;
     var firstAtrulesAllowed = true;
@@ -89,18 +82,23 @@ var blockNum = 1;
     var usageData = false;
+    var info = ast.info || null;
 
-    ast = ast || [{}, 'stylesheet'];
-
-    if (typeof ast[0] === 'string') {
-        injectInfo([ast]);
-    }
-
-    if (ast[1] !== 'stylesheet') {
+    if (ast.type !== 'StyleSheet') {
         blockMode = true;
-        ast = [null, 'stylesheet',
-            [null, 'ruleset',
-                [null, 'selector',
-                    [null, 'simpleselector', [null, 'ident', 'x']]],
-                ast
-            ]
-        ];
+        ast = {
+            type: 'StyleSheet',
+            rules: new List([{
+                type: 'Ruleset',
+                selector: {
+                    type: 'Selector',
+                    selectors: new List([{
+                        type: 'SimpleSelector',
+                        sequence: new List([{
+                            type: 'Identifier',
+                            name: 'x'
+                        }])
+                    }])
+                },
+                block: ast
+            }])
+        };
     }
@@ -113,3 +111,4 @@
     do {
-        block = readBlock(ast, block.offset);
+        block = readBlock(ast);
+        // console.log(JSON.stringify(block.stylesheet, null, 2));
         block.stylesheet.firstAtrulesAllowed = firstAtrulesAllowed;
@@ -134,6 +133,3 @@ block.stylesheet = compressBlock(block.stylesheet, usageData, blockNum++, logger);
 
-            result.insert(List.createItem({
-                type: 'Comment',
-                value: block.comment[2]
-            }));
+            result.insert(List.createItem(block.comment));
 
@@ -159,9 +155,14 @@ // add \n after comment if block is not empty
         result.appendList(blockRules);
-    } while (block.offset < ast.length);
+    } while (!ast.rules.isEmpty());
 
     if (blockMode) {
-        result = result.first().block;
+        result = !result.isEmpty() ? result.first().block : {
+            type: 'Block',
+            info: info,
+            declarations: new List()
+        };
     } else {
         result = {
             type: 'StyleSheet',
+            info: info,
             rules: result
@@ -171,7 +172,5 @@ };
 
-    if (!options.outputAst || options.outputAst === 'gonzales') {
-        return convertToGonzales(result);
-    }
-
-    return result;
+    return {
+        ast: result
+    };
 };

lib/compressor/restructure/1-initialMergeRuleset.js

 var utils = require('./utils.js');
-var internalWalkRules = require('../ast/walk.js').rules;
+var walkRules = require('../../utils/walk.js').rules;
 
@@ -27,3 +27,3 @@ function processRuleset(node, item, list) {
             // try to join by declarations
-            if (utils.isEqualLists(declarations, prevDeclarations)) {
+            if (utils.isEqualDeclarations(declarations, prevDeclarations)) {
                 utils.addSelectors(prevSelectors, selectors);
@@ -44,3 +44,3 @@ list.remove(item);
 module.exports = function initialMergeRuleset(ast) {
-    internalWalkRules(ast, function(node, item, list) {
+    walkRules(ast, function(node, item, list) {
         if (node.type === 'Ruleset') {
@@ -47,0 +47,0 @@ processRuleset(node, item, list);

lib/compressor/restructure/2-mergeAtrule.js

@@ -1,2 +0,2 @@
-var internalWalkRulesRight = require('../ast/walk.js').rulesRight;
+var walkRulesRight = require('../../utils/walk.js').rulesRight;
 
@@ -30,3 +30,3 @@ function isMediaRule(node) {
 module.exports = function rejoinAtrule(ast) {
-    internalWalkRulesRight(ast, function(node, item, list) {
+    walkRulesRight(ast, function(node, item, list) {
         if (node.type === 'Atrule') {
@@ -33,0 +33,0 @@ processAtrule(node, item, list);

lib/compressor/restructure/3-disjoinRuleset.js

 var List = require('../../utils/list.js');
-var internalWalkRulesRight = require('../ast/walk.js').rulesRight;
+var walkRulesRight = require('../../utils/walk.js').rulesRight;
 
@@ -37,3 +37,3 @@ function processRuleset(node, item, list) {
 module.exports = function disjoinRuleset(ast) {
-    internalWalkRulesRight(ast, function(node, item, list) {
+    walkRulesRight(ast, function(node, item, list) {
         if (node.type === 'Ruleset') {
@@ -40,0 +40,0 @@ processRuleset(node, item, list);

lib/compressor/restructure/4-restructShorthand.js

 var List = require('../../utils/list.js');
-var translate = require('../ast/translate.js');
-var internalWalkRulesRight = require('../ast/walk.js').rulesRight;
+var translate = require('../../utils/translate.js');
+var walkRulesRight = require('../../utils/walk.js').rulesRight;
 
@@ -387,3 +387,3 @@ var REPLACE = 1;
 
-    internalWalkRulesRight(ast, function(node) {
+    walkRulesRight(ast, function(node) {
         if (node.type !== 'Ruleset') {
@@ -390,0 +390,0 @@ return;

lib/compressor/restructure/6-restructBlock.js

@@ -1,5 +0,5 @@
-var resolveProperty = require('../ast/names.js').property;
-var resolveKeyword = require('../ast/names.js').keyword;
-var internalWalkRulesRight = require('../ast/walk.js').rulesRight;
-var translate = require('../ast/translate.js');
+var resolveProperty = require('../../utils/names.js').property;
+var resolveKeyword = require('../../utils/names.js').keyword;
+var walkRulesRight = require('../../utils/walk.js').rulesRight;
+var translate = require('../../utils/translate.js');
 var dontRestructure = {
@@ -222,3 +222,3 @@ 'src': 1 // https://github.com/afelix/csso/issues/50
 
-    internalWalkRulesRight(ast, function(node, item, list) {
+    walkRulesRight(ast, function(node, item, list) {
         if (node.type !== 'Ruleset') {
@@ -225,0 +225,0 @@ return;

lib/compressor/restructure/7-mergeRuleset.js

 var utils = require('./utils.js');
-var internalWalkRules = require('../ast/walk.js').rules;
+var walkRules = require('../../utils/walk.js').rules;
 
@@ -82,3 +82,3 @@ /*
 module.exports = function mergeRuleset(ast) {
-    internalWalkRules(ast, function(node, item, list) {
+    walkRules(ast, function(node, item, list) {
         if (node.type === 'Ruleset') {
@@ -85,0 +85,0 @@ processRuleset(node, item, list);

lib/compressor/restructure/8-restructRuleset.js

 var List = require('../../utils/list.js');
 var utils = require('./utils.js');
-var internalWalkRulesRight = require('../ast/walk.js').rulesRight;
+var walkRulesRight = require('../../utils/walk.js').rulesRight;
 
@@ -137,3 +137,3 @@ function calcSelectorLength(list) {
 module.exports = function restructRuleset(ast) {
-    internalWalkRulesRight(ast, function(node, item, list) {
+    walkRulesRight(ast, function(node, item, list) {
         if (node.type === 'Ruleset') {
@@ -140,0 +140,0 @@ processRuleset.call(this, node, item, list);

lib/compressor/restructure/prepare/createDeclarationIndexer.js

@@ -1,2 +0,2 @@
-var translate = require('../../ast/translate.js');
+var translate = require('../../../utils/translate.js');
 
@@ -3,0 +3,0 @@ function Index() {

lib/compressor/restructure/prepare/index.js

@@ -1,4 +0,4 @@
-var internalWalkRules = require('../../ast/walk.js').rules;
-var resolveKeyword = require('../../ast/names.js').keyword;
-var translate = require('../../ast/translate.js');
+var resolveKeyword = require('../../../utils/names.js').keyword;
+var walkRules = require('../../../utils/walk.js').rules;
+var translate = require('../../../utils/translate.js');
 var createDeclarationIndexer = require('./createDeclarationIndexer.js');
@@ -37,3 +37,3 @@ var processSelector = require('./processSelector.js');
 
-    internalWalkRules(ast, function(node) {
+    walkRules(ast, function(node) {
         walk(node, markDeclaration, usageData);
@@ -40,0 +40,0 @@ });

lib/compressor/restructure/prepare/processSelector.js

@@ -1,2 +0,2 @@
-var translate = require('../../ast/translate.js');
+var translate = require('../../../utils/translate.js');
 var specificity = require('./specificity.js');
@@ -3,0 +3,0 @@

lib/compressor/restructure/utils.js

@@ -7,3 +7,3 @@ var hasOwnProperty = Object.prototype.hasOwnProperty;
 
-    while (cursor1 && cursor2 && cursor1.data.id === cursor2.data.id) {
+    while (cursor1 !== null && cursor2 !== null && cursor1.data.id === cursor2.data.id) {
         cursor1 = cursor1.next;
@@ -20,3 +20,3 @@ cursor2 = cursor2.next;
 
-    while (cursor1 && cursor2 && cursor1.data.id === cursor2.data.id) {
+    while (cursor1 !== null && cursor2 !== null && cursor1.data.id === cursor2.data.id) {
         cursor1 = cursor1.next;
@@ -23,0 +23,0 @@ cursor2 = cursor2.next;

lib/index.js

 var parse = require('./parser');
 var compress = require('./compressor');
-var traslateInternal = require('./compressor/ast/translate');
-var traslateInternalWithSourceMap = require('./compressor/ast/translateWithSourceMap');
-var internalWalkers = require('./compressor/ast/walk');
-var walk = require('./utils/walker');
 var translate = require('./utils/translate');
-var stringify = require('./utils/stringify');
-var cleanInfo = require('./utils/cleanInfo');
+var translateWithSourceMap = require('./utils/translateWithSourceMap');
+var walkers = require('./utils/walk');
 
-var justDoIt = function(src, noStructureOptimizations, needInfo) {
-    console.warn('`csso.justDoIt()` method is deprecated, use `csso.minify()` instead');
-
-    var ast = parse(src, 'stylesheet', needInfo);
-    var compressed = compress(ast, {
-        restructure: !noStructureOptimizations,
-        outputAst: 'internal'
-    });
-
-    return traslateInternal(compressed);
-};
-
 function debugOutput(name, options, startTime, data) {
@@ -42,3 +26,3 @@ if (options.debug) {
         if (level > 1 && ast) {
-            var css = traslateInternal(ast, true);
+            var css = translate(ast, true);
 
@@ -70,3 +54,2 @@ // when level 2, limit css to 256 symbols
     options = copy(options);
-    options.outputAst = 'internal';
 
@@ -88,6 +71,6 @@ if (typeof options.logger !== 'function' && options.debug) {
     var ast = debugOutput('parsing', options, Date.now(),
-        parse(source, context, {
+        parse(source, {
+            context: context,
             filename: filename,
-            positions: Boolean(options.sourceMap),
-            needInfo: true
+            positions: Boolean(options.sourceMap)
         })
@@ -97,3 +80,3 @@ );
     // compress
-    var compressedAst = debugOutput('compress', options, Date.now(),
+    var compressResult = debugOutput('compress', options, Date.now(),
         compress(ast, buildCompressOptions(options))
@@ -105,3 +88,3 @@ );
         result = debugOutput('translateWithSourceMap', options, Date.now(), (function() {
-            var tmp = traslateInternalWithSourceMap(compressedAst);
+            var tmp = translateWithSourceMap(compressResult.ast);
             tmp.map._file = filename; // since other tools can relay on file in source map transform chain
@@ -112,5 +95,6 @@ tmp.map.setSourceContent(filename, source);
     } else {
-        result = debugOutput('translate', options, Date.now(),
-            traslateInternal(compressedAst)
-        );
+        result = debugOutput('translate', options, Date.now(), {
+            css: translate(compressResult.ast),
+            map: null
+        });
     }
@@ -126,3 +110,3 @@
 function minifyBlock(source, options) {
-    return minify('declarations', source, options);
+    return minify('block', source, options);
 }
@@ -133,28 +117,16 @@
 
-    // main method
+    // main methods
     minify: minifyStylesheet,
     minifyBlock: minifyBlock,
 
-    // utils
+    // step by step
     parse: parse,
     compress: compress,
     translate: translate,
+    translateWithSourceMap: translateWithSourceMap,
 
-    walk: walk,
-    stringify: stringify,
-    cleanInfo: cleanInfo,
-
-    // internal ast
-    internal: {
-        fromGonzales: require('./compressor/ast/gonzalesToInternal'),
-        toGonzales: require('./compressor/ast/internalToGonzales'),
-        translate: traslateInternal,
-        translateWithSourceMap: traslateInternalWithSourceMap,
-        walk: internalWalkers.all,
-        walkRules: internalWalkers.rules,
-        walkRulesRight: internalWalkers.rulesRight
-    },
-
-    // deprecated
-    justDoIt: justDoIt
+    // walkers
+    walk: walkers.all,
+    walkRules: walkers.rules,
+    walkRulesRight: walkers.rulesRight
 };

lib/parser/const.js

@@ -47,51 +47,1 @@ exports.TokenType = {
 // }
-
-exports.NodeType = {
-    AtkeywordType: 'atkeyword',
-    AtrulebType: 'atruleb',
-    AtrulerqType: 'atrulerq',
-    AtrulersType: 'atrulers',
-    AtrulerType: 'atruler',
-    AtrulesType: 'atrules',
-    AttribType: 'attrib',
-    AttrselectorType: 'attrselector',
-    BlockType: 'block',
-    BracesType: 'braces',
-    ClassType: 'clazz',
-    CombinatorType: 'combinator',
-    CommentType: 'comment',
-    DeclarationType: 'declaration',
-    DecldelimType: 'decldelim',
-    DelimType: 'delim',
-    DimensionType: 'dimension',
-    FilterType: 'filter',
-    FiltervType: 'filterv',
-    FunctionBodyType: 'functionBody',
-    FunctionExpressionType: 'functionExpression',
-    FunctionType: 'funktion',
-    IdentType: 'ident',
-    ImportantType: 'important',
-    NamespaceType: 'namespace',
-    NthselectorType: 'nthselector',
-    NthType: 'nth',
-    NumberType: 'number',
-    OperatorType: 'operator',
-    PercentageType: 'percentage',
-    ProgidType: 'progid',
-    PropertyType: 'property',
-    PseudocType: 'pseudoc',
-    PseudoeType: 'pseudoe',
-    RawType: 'raw',
-    RulesetType: 'ruleset',
-    SelectorType: 'selector',
-    ShashType: 'shash',
-    SimpleselectorType: 'simpleselector',
-    StringType: 'string',
-    StylesheetType: 'stylesheet',
-    SType: 's',
-    UnaryType: 'unary',
-    UnknownType: 'unknown',
-    UriType: 'uri',
-    ValueType: 'value',
-    VhashType: 'vhash'
-};

lib/parser/index.js

 'use strict';
 
-var TokenType = require('./const.js').TokenType;
-var NodeType = require('./const.js').NodeType;
-var tokenize = require('./tokenize.js');
-var cleanInfo = require('../utils/cleanInfo.js');
+var TokenType = require('./const').TokenType;
+var Scanner = require('./scanner');
+var List = require('../utils/list');
 var needPositions;
 var filename;
-var tokens;
-var pos;
+var scanner;
 
@@ -30,51 +28,12 @@ var SCOPE_ATRULE_EXPRESSION = 1;
 
-var rules = {
-    'atkeyword': getAtkeyword,
-    'atrule': getAtrule,
-    'attribute': getAttribute,
-    'block': getBlockWithBrackets,
-    'braces': getBraces,
-    'class': getClass,
-    'combinator': getCombinator,
-    'comment': getComment,
-    'declaration': getDeclaration,
-    'declarations': getBlock,
-    'dimension': getDimension,
-    'function': getFunction,
-    'ident': getIdentifier,
-    'important': getImportant,
-    'nth': getNth,
-    'nthselector': getNthSelector,
-    'number': getNumber,
-    'operator': getOperator,
-    'percentage': getPercentage,
-    'progid': getProgid,
-    'property': getProperty,
-    'pseudoClass': getPseudoClass,
-    'pseudoElement': getPseudoElement,
-    'ruleset': getRuleset,
-    'selector': getSelector,
-    'shash': getShash,
-    'simpleselector': getSimpleSelector,
-    'string': getString,
-    'stylesheet': getStylesheet,
-    'unary': getUnary,
-    'unknown': getUnknown,
-    'uri': getUri,
-    'value': getValue,
-    'vhash': getVhash,
-
-    // TODO: remove in 2.0
-    // for backward capability
-    'atruleb': getAtrule,
-    'atruler': getAtrule,
-    'atrules': getAtrule,
-    'attrib': getAttribute,
-    'attrselector': getAttrselector,
-    'clazz': getClass,
-    'filter': getDeclaration,
-    'functionExpression': getOldIEExpression,
-    'funktion': getFunction,
-    'pseudoc': getPseudoClass,
-    'pseudoe': getPseudoElement
+var initialContext = {
+    stylesheet: getStylesheet,
+    atrule: getAtrule,
+    atruleExpression: getAtruleExpression,
+    ruleset: getRuleset,
+    selector: getSelector,
+    simpleSelector: getSimpleSelector,
+    block: getBlock,
+    declaration: getDeclaration,
+    value: getValue
 };
@@ -93,15 +52,11 @@
 
-    if (tokens.length) {
-        if (pos < tokens.length) {
-            line = tokens[pos].line;
-            column = tokens[pos].column;
-        } else {
-            pos = tokens.length - 1;
-            lines = tokens[pos].value.trimRight().split(/\n|\r\n?|\f/);
-            line = tokens[pos].line + lines.length - 1;
-            column = lines.length > 1
-                ? lines[lines.length - 1].length + 1
-                : tokens[pos].column + lines[lines.length - 1].length;
-        }
-
+    if (scanner.token !== null) {
+        line = scanner.token.line;
+        column = scanner.token.column;
+    } else if (scanner.prevToken !== null) {
+        lines = scanner.prevToken.value.trimRight().split(/\n|\r\n?|\f/);
+        line = scanner.prevToken.line + lines.length - 1;
+        column = lines.length > 1
+            ? lines[lines.length - 1].length + 1
+            : scanner.prevToken.column + lines[lines.length - 1].length;
     }
@@ -119,4 +74,4 @@
 function eat(tokenType) {
-    if (pos < tokens.length && tokens[pos].type === tokenType) {
-        pos++;
+    if (scanner.token !== null && scanner.token.type === tokenType) {
+        scanner.next();
         return true;
@@ -129,8 +84,7 @@ }
 function expectIdentifier(name, eat) {
-    if (pos < tokens.length) {
-        var token = tokens[pos];
-        if (token.type === TokenType.Identifier &&
-            token.value.toLowerCase() === name) {
+    if (scanner.token !== null) {
+        if (scanner.token.type === TokenType.Identifier &&
+            scanner.token.value.toLowerCase() === name) {
             if (eat) {
-                pos++;
+                scanner.next();
             }
@@ -146,4 +100,4 @@
 function expectAny(what) {
-    if (pos < tokens.length) {
-        for (var i = 1, type = tokens[pos].type; i < arguments.length; i++) {
+    if (scanner.token !== null) {
+        for (var i = 1, type = scanner.token.type; i < arguments.length; i++) {
             if (type === arguments[i]) {
@@ -158,11 +112,9 @@ return true;
 
-function getInfo(idx) {
-    if (needPositions && idx < tokens.length) {
-        var token = tokens[idx];
-
+function getInfo() {
+    if (needPositions && scanner.token) {
         return {
             source: filename,
-            offset: token.offset,
-            line: token.line,
-            column: token.column
+            offset: scanner.token.offset,
+            line: scanner.token.line,
+            column: scanner.token.column
         };
@@ -175,22 +127,44 @@ }
 
+function removeTrailingSpaces(list) {
+    while (list.tail) {
+        if (list.tail.data.type === 'Space') {
+            list.remove(list.tail);
+        } else {
+            break;
+        }
+    }
+}
+
 function getStylesheet(nested) {
-    var stylesheet = [getInfo(pos), NodeType.StylesheetType];
+    var child = null;
+    var node = {
+        type: 'StyleSheet',
+        info: getInfo(),
+        rules: new List()
+    };
 
     scan:
-    while (pos < tokens.length) {
-        switch (tokens[pos].type) {
+    while (scanner.token !== null) {
+        switch (scanner.token.type) {
             case TokenType.Space:
-                stylesheet.push(getS());
+                scanner.next();
+                child = null;
                 break;
 
             case TokenType.Comment:
-                stylesheet.push(getComment());
+                // ignore comments except exclamation comments on top level
+                if (nested || scanner.token.value.charAt(2) !== '!') {
+                    scanner.next();
+                    child = null;
+                } else {
+                    child = getComment();
+                }
                 break;
 
             case TokenType.Unknown:
-                stylesheet.push(getUnknown());
+                child = getUnknown();
                 break;
 
             case TokenType.CommercialAt:
-                stylesheet.push(getAtrule());
+                child = getAtrule();
                 break;
@@ -206,13 +180,32 @@
             default:
-                stylesheet.push(getRuleset());
+                child = getRuleset();
         }
+
+        if (child !== null) {
+            node.rules.insert(List.createItem(child));
+        }
     }
 
-    return stylesheet;
+    return node;
 }
 
-function isBlockAtrule(i) {
-    for (i++; i < tokens.length; i++) {
-        var type = tokens[i].type;
+// '//' ...
+// TODO: remove it as wrong thing
+function getUnknown() {
+    var info = getInfo();
+    var value = scanner.token.value;
 
+    eat(TokenType.Unknown);
+
+    return {
+        type: 'Unknown',
+        info: info,
+        value: value
+    };
+}
+
+function isBlockAtrule() {
+    for (var offset = 1, cursor; cursor = scanner.lookup(offset); offset++) {
+        var type = cursor.type;
+
         if (type === TokenType.RightCurlyBracket) {
@@ -231,82 +224,117 @@ return true;
 
-function getAtkeyword() {
-    eat(TokenType.CommercialAt);
+function getAtruleExpression() {
+    var child = null;
+    var node = {
+        type: 'AtruleExpression',
+        info: getInfo(),
+        sequence: new List()
+    };
 
-    return [getInfo(pos - 1), NodeType.AtkeywordType, getIdentifier()];
-}
-
-function getAtrule() {
-    var node = [getInfo(pos), NodeType.AtrulesType, getAtkeyword(pos)];
-
     scan:
-    while (pos < tokens.length) {
-        switch (tokens[pos].type) {
+    while (scanner.token !== null) {
+        switch (scanner.token.type) {
             case TokenType.Semicolon:
-                pos++;
                 break scan;
 
             case TokenType.LeftCurlyBracket:
-                if (isBlockAtrule(pos)) {
-                    node[1] = NodeType.AtrulebType;
-                    node.push(getBlockWithBrackets());
-                } else {
-                    node[1] = NodeType.AtrulerType;
-                    node.push([
-                        {},
-                        NodeType.AtrulerqType
-                    ].concat(node.splice(3)));
-
-                    pos++;  // {
-
-                    var stylesheet = getStylesheet(true);
-                    stylesheet[1] = NodeType.AtrulersType;
-                    node.push(stylesheet);
-
-                    pos++;  // }
-                }
                 break scan;
 
             case TokenType.Space:
-                node.push(getS());
+                if (node.sequence.isEmpty()) {
+                    scanner.next(); // ignore spaces in beginning
+                    child = null;
+                } else {
+                    child = getS();
+                }
                 break;
 
-            case TokenType.Comment:
-                node.push(getComment());
+            case TokenType.Comment: // ignore comments
+                scanner.next();
+                child = null;
                 break;
 
             case TokenType.Comma:
-                node.push(getOperator());
+                child = getOperator();
                 break;
 
             case TokenType.Colon:
-                node.push(getPseudo());
+                child = getPseudo();
                 break;
 
             case TokenType.LeftParenthesis:
-                node.push(getBraces(SCOPE_ATRULE_EXPRESSION));
+                child = getBraces(SCOPE_ATRULE_EXPRESSION);
                 break;
 
             default:
-                node.push(getAny(SCOPE_ATRULE_EXPRESSION));
+                child = getAny(SCOPE_ATRULE_EXPRESSION);
         }
+
+        if (child !== null) {
+            node.sequence.insert(List.createItem(child));
+        }
     }
 
+    removeTrailingSpaces(node.sequence);
+
     return node;
 }
 
+function getAtrule() {
+    eat(TokenType.CommercialAt);
+
+    var node = {
+        type: 'Atrule',
+        info: getInfo(),
+        name: readIdent(false),
+        expression: getAtruleExpression(),
+        block: null
+    };
+
+    if (scanner.token !== null) {
+        switch (scanner.token.type) {
+            case TokenType.Semicolon:
+                scanner.next();  // {
+                break;
+
+            case TokenType.LeftCurlyBracket:
+                scanner.next();  // {
+
+                if (isBlockAtrule()) {
+                    node.block = getBlock();
+                } else {
+                    node.block = getStylesheet(true);
+                }
+
+                eat(TokenType.RightCurlyBracket);
+                break;
+
+            default:
+                parseError('Unexpected input');
+        }
+    }
+
+    return node;
+}
+
 function getRuleset() {
-    return [
-        getInfo(pos),
-        NodeType.RulesetType,
-        getSelector(),
-        getBlockWithBrackets()
-    ];
+    return {
+        type: 'Ruleset',
+        info: getInfo(),
+        selector: getSelector(),
+        block: getBlockWithBrackets()
+    };
 }
 
 function getSelector() {
-    var selector = [getInfo(pos), NodeType.SelectorType];
+    var isBadSelector = false;
+    var lastComma = true;
+    var node = {
+        type: 'Selector',
+        info: getInfo(),
+        selectors: new List()
+    };
 
     scan:
-    while (pos < tokens.length) {
-        switch (tokens[pos].type) {
+    while (scanner.token !== null) {
+        switch (scanner.token.type) {
             case TokenType.LeftCurlyBracket:
@@ -316,22 +344,48 @@ break scan;
             case TokenType.Comma:
-                selector.push([
-                    getInfo(pos++),
-                    NodeType.DelimType
-                ]);
+                if (lastComma) {
+                    isBadSelector = true;
+                }
+
+                lastComma = true;
+                scanner.next();
                 break;
 
             default:
-                selector.push(getSimpleSelector());
+                if (!lastComma) {
+                    isBadSelector = true;
+                }
+
+                lastComma = false;
+                node.selectors.insert(List.createItem(getSimpleSelector()));
+
+                if (node.selectors.tail.data.sequence.isEmpty()) {
+                    isBadSelector = true;
+                }
         }
     }
 
-    return selector;
+    if (lastComma) {
+        isBadSelector = true;
+        // parseError('Unexpected trailing comma');
+    }
+
+    if (isBadSelector) {
+        node.selectors = new List();
+    }
+
+    return node;
 }
 
 function getSimpleSelector(nested) {
-    var node = [getInfo(pos), NodeType.SimpleselectorType];
+    var child = null;
+    var combinator = null;
+    var node = {
+        type: 'SimpleSelector',
+        info: getInfo(),
+        sequence: new List()
+    };
 
     scan:
-    while (pos < tokens.length) {
-        switch (tokens[pos].type) {
+    while (scanner.token !== null) {
+        switch (scanner.token.type) {
             case TokenType.Comma:
@@ -354,8 +408,14 @@ break scan;
 
-            case TokenType.Space:
-                node.push(getS());
+            case TokenType.Comment:
+                scanner.next();
+                child = null;
                 break;
 
-            case TokenType.Comment:
-                node.push(getComment());
+            case TokenType.Space:
+                child = null;
+                if (!combinator && node.sequence.head) {
+                    combinator = getCombinator();
+                } else {
+                    scanner.next();
+                }
                 break;
@@ -367,30 +427,35 @@
             case TokenType.Solidus:
-                node.push(getCombinator());
+                if (combinator && combinator.name !== ' ') {
+                    parseError('Unexpected combinator');
+                }
+
+                child = null;
+                combinator = getCombinator();
                 break;
 
             case TokenType.FullStop:
-                node.push(getClass());
+                child = getClass();
                 break;
 
             case TokenType.LeftSquareBracket:
-                node.push(getAttribute());
+                child = getAttribute();
                 break;
 
             case TokenType.NumberSign:
-                node.push(getShash());
+                child = getShash();
                 break;
 
             case TokenType.Colon:
-                node.push(getPseudo());
+                child = getPseudo();
                 break;
 
-            case TokenType.HyphenMinus:
             case TokenType.LowLine:
             case TokenType.Identifier:
             case TokenType.Asterisk:
+                child = getNamespacedIdentifier(false);
+                break;
+
+            case TokenType.HyphenMinus:
             case TokenType.DecimalNumber:
-                node.push(
-                    tryGetPercentage() ||
-                    getNamespacedIdentifier(false)
-                );
+                child = tryGetPercentage() || getNamespacedIdentifier(false);
                 break;
@@ -401,14 +466,16 @@
         }
-    }
 
-    return node;
-}
+        if (child !== null) {
+            if (combinator !== null) {
+                node.sequence.insert(List.createItem(combinator));
+                combinator = null;
+            }
 
-function getBlockWithBrackets() {
-    var info = getInfo(pos);
-    var node;
+            node.sequence.insert(List.createItem(child));
+        }
+    }
 
-    eat(TokenType.LeftCurlyBracket);
-    node = getBlock(info);
-    eat(TokenType.RightCurlyBracket);
+    if (combinator && combinator.name !== ' ') {
+        parseError('Unexpected combinator');
+    }
 
@@ -418,8 +485,9 @@ return node;
 
-function getBlock(info) {
-    var node = [info || getInfo(pos), NodeType.BlockType];
+function getDeclarations() {
+    var child = null;
+    var declarations = new List();
 
     scan:
-    while (pos < tokens.length) {
-        switch (tokens[pos].type) {
+    while (scanner.token !== null) {
+        switch (scanner.token.type) {
             case TokenType.RightCurlyBracket:
@@ -429,28 +497,51 @@ break scan;
             case TokenType.Space:
-                node.push(getS());
-                break;
-
             case TokenType.Comment:
-                node.push(getComment());
+                scanner.next();
+                child = null;
                 break;
 
             case TokenType.Semicolon: // ;
-                node.push([
-                    getInfo(pos++),
-                    NodeType.DecldelimType
-                ]);
+                scanner.next();
+                child = null;
                 break;
 
             default:
-                node.push(getDeclaration());
+                child = getDeclaration();
         }
+
+        if (child !== null) {
+            declarations.insert(List.createItem(child));
+        }
     }
 
+    return declarations;
+}
+
+function getBlockWithBrackets() {
+    var info = getInfo();
+    var node;
+
+    eat(TokenType.LeftCurlyBracket);
+    node = {
+        type: 'Block',
+        info: info,
+        declarations: getDeclarations()
+    };
+    eat(TokenType.RightCurlyBracket);
+
     return node;
 }
 
+function getBlock() {
+    return {
+        type: 'Block',
+        info: getInfo(),
+        declarations: getDeclarations()
+    };
+}
+
 function getDeclaration(nested) {
-    var startPos = pos;
-    var info = getInfo(pos);
+    var info = getInfo();
     var property = getProperty();
+    var value;
 
@@ -460,30 +551,26 @@ eat(TokenType.Colon);
     // check it's a filter
-    for (var j = startPos; j < pos; j++) {
-        if (tokens[j].value.toLowerCase() === 'filter') {
-            if (checkProgid(pos)) {
-                return [
-                    info,
-                    NodeType.FilterType,
-                    property,
-                    getFilterv()
-                ];
-            }
-            break;
-        }
+    if (/filter$/.test(property.name.toLowerCase()) && checkProgid()) {
+        value = getFilterValue();
+    } else {
+        value = getValue(nested);
     }
 
-    return [
-        info,
-        NodeType.DeclarationType,
-        property,
-        getValue(nested)
-    ];
+    return {
+        type: 'Declaration',
+        info: info,
+        property: property,
+        value: value
+    };
 }
 
 function getProperty() {
-    var info = getInfo(pos);
     var name = '';
+    var node = {
+        type: 'Property',
+        info: getInfo(),
+        name: null
+    };
 
-    while (pos < tokens.length) {
-        var type = tokens[pos].type;
+    for (; scanner.token !== null; scanner.next()) {
+        var type = scanner.token.type;
 
@@ -496,22 +583,26 @@ if (type !== TokenType.Solidus &&
 
-        name += tokens[pos++].value;
+        name += scanner.token.value;
     }
 
-    return readSC([
-        info,
-        NodeType.PropertyType,
-        [
-            info,
-            NodeType.IdentType,
-            name + readIdent(true)
-        ]
-    ]);
+    node.name = name + readIdent(true);
+
+    readSC();
+
+    return node;
 }
 
 function getValue(nested) {
-    var node = [getInfo(pos), NodeType.ValueType];
+    var child = null;
+    var node = {
+        type: 'Value',
+        info: getInfo(),
+        important: false,
+        sequence: new List()
+    };
 
+    readSC();
+
     scan:
-    while (pos < tokens.length) {
-        switch (tokens[pos].type) {
+    while (scanner.token !== null) {
+        switch (scanner.token.type) {
             case TokenType.RightCurlyBracket:
@@ -528,11 +619,12 @@ case TokenType.Semicolon:
             case TokenType.Space:
-                node.push(getS());
+                child = getS();
                 break;
 
-            case TokenType.Comment:
-                node.push(getComment());
+            case TokenType.Comment: // ignore comments
+                scanner.next();
+                child = null;
                 break;
 
             case TokenType.NumberSign:
-                node.push(getVhash());
+                child = getVhash();
                 break;
@@ -542,3 +634,3 @@
             case TokenType.Comma:
-                node.push(getOperator());
+                child = getOperator();
                 break;
@@ -548,7 +640,8 @@
             case TokenType.LeftSquareBracket:
-                node.push(getBraces(SCOPE_VALUE));
+                child = getBraces(SCOPE_VALUE);
                 break;
 
             case TokenType.ExclamationMark:
-                node.push(getImportant());
+                node.important = getImportant();
+                child = null;
                 break;
@@ -558,14 +651,15 @@
                 // check for unicode range: U+0F00, U+0F00-0FFF, u+0F00??
-                if (tokens[pos].type === TokenType.Identifier) {
-                    var prefix = tokens[pos].value;
-                    if ((prefix === 'U' || prefix === 'u') &&
-                        pos + 1 < tokens.length &&
-                        tokens[pos + 1].type === TokenType.PlusSign) {
-                        pos += 2;
+                if (scanner.token.type === TokenType.Identifier) {
+                    var prefix = scanner.token.value;
+                    if (prefix === 'U' || prefix === 'u') {
+                        if (scanner.lookupType(1, TokenType.PlusSign)) {
+                            scanner.next(); // U or u
+                            scanner.next(); // +
 
-                        node.push([
-                            getInfo(pos),
-                            NodeType.IdentType,
-                            prefix + '+' + getUnicodeRange(true)
-                        ]);
+                            child = {
+                                type: 'Identifier',
+                                info: getInfo(), // FIXME: wrong position
+                                name: prefix + '+' + readUnicodeRange(true)
+                            };
+                        }
                         break;
@@ -575,6 +669,12 @@ }
 
-                node.push(getAny(SCOPE_VALUE));
+                child = getAny(SCOPE_VALUE);
         }
+
+        if (child !== null) {
+            node.sequence.insert(List.createItem(child));
+        }
     }
 
+    removeTrailingSpaces(node.sequence);
+
     return node;
@@ -585,5 +685,3 @@ }
 function getAny(scope) {
-    var startPos = pos;
-
-    switch (tokens[pos].type) {
+    switch (scanner.token.type) {
         case TokenType.String:
@@ -603,7 +701,7 @@ return getString();
             if (number !== null) {
-                if (pos < tokens.length) {
-                    if (tokens[pos].type === TokenType.PercentSign) {
-                        return getPercentage(startPos, number);
-                    } else if (tokens[pos].type === TokenType.Identifier) {
-                        return getDimension(startPos, number);
+                if (scanner.token !== null) {
+                    if (scanner.token.type === TokenType.PercentSign) {
+                        return getPercentage(number);
+                    } else if (scanner.token.type === TokenType.Identifier) {
+                        return getDimension(number.value);
                     }
@@ -615,11 +713,12 @@ }
 
-            if (tokens[pos].type === TokenType.HyphenMinus &&
-                pos < tokens.length &&
-                (tokens[pos + 1].type === TokenType.Identifier || tokens[pos + 1].type === TokenType.HyphenMinus)) {
-                break;
+            if (scanner.token.type === TokenType.HyphenMinus) {
+                var next = scanner.lookup(1);
+                if (next && (next.type === TokenType.Identifier || next.type === TokenType.HyphenMinus)) {
+                    break;
+                }
             }
 
-            if (tokens[pos].type === TokenType.HyphenMinus ||
-                tokens[pos].type === TokenType.PlusSign) {
-                return getUnary();
+            if (scanner.token.type === TokenType.HyphenMinus ||
+                scanner.token.type === TokenType.PlusSign) {
+                return getOperator();
             }
@@ -633,7 +732,6 @@
 
-    var ident = getIdentifier();
+    var ident = getIdentifier(false);
 
-    if (pos < tokens.length && tokens[pos].type === TokenType.LeftParenthesis) {
-        pos = startPos;
-        return getFunction(scope);
+    if (scanner.token !== null && scanner.token.type === TokenType.LeftParenthesis) {
+        return getFunction(scope, ident);
     }
@@ -644,35 +742,65 @@
 
+function readAttrselector() {
+    expectAny('Attribute selector (=, ~=, ^=, $=, *=, |=)',
+        TokenType.EqualsSign,        // =
+        TokenType.Tilde,             // ~=
+        TokenType.CircumflexAccent,  // ^=
+        TokenType.DollarSign,        // $=
+        TokenType.Asterisk,          // *=
+        TokenType.VerticalLine       // |=
+    );
+
+    var name;
+
+    if (scanner.token.type === TokenType.EqualsSign) {
+        name = '=';
+        scanner.next();
+    } else {
+        name = scanner.token.value + '=';
+        scanner.next();
+        eat(TokenType.EqualsSign);
+    }
+
+    return name;
+}
+
 // '[' S* attrib_name ']'
-// '[' S* attrib_name attrib_match [ IDENT | STRING ] S* attrib_flags? ']'
+// '[' S* attrib_name S* attrib_match S* [ IDENT | STRING ] S* attrib_flags? S* ']'
 function getAttribute() {
-    var node = [getInfo(pos), NodeType.AttribType];
+    var node = {
+        type: 'Attribute',
+        info: getInfo(),
+        name: null,
+        operator: null,
+        value: null,
+        flags: null
+    };
 
     eat(TokenType.LeftSquareBracket);
 
-    readSC(node);
+    readSC();
 
-    node.push(getNamespacedIdentifier(true));
+    node.name = getNamespacedIdentifier(true);
 
-    readSC(node);
+    readSC();
 
-    if (pos < tokens.length && tokens[pos].type !== TokenType.RightSquareBracket) {
-        node.push(getAttrselector());
-        readSC(node);
+    if (scanner.token !== null && scanner.token.type !== TokenType.RightSquareBracket) {
+        node.operator = readAttrselector();
 
-        if (pos < tokens.length && tokens[pos].type === TokenType.String) {
-            node.push(getString());
+        readSC();
+
+        if (scanner.token !== null && scanner.token.type === TokenType.String) {
+            node.value = getString();
         } else {
-            node.push(getIdentifier());
+            node.value = getIdentifier(false);
         }
 
-        readSC(node);
+        readSC();
 
         // attribute flags
-        if (pos < tokens.length && tokens[pos].type === TokenType.Identifier) {
-            node.push([
-                getInfo(pos),
-                'attribFlags',
-                tokens[pos++].value
-            ]);
-            readSC(node);
+        if (scanner.token !== null && scanner.token.type === TokenType.Identifier) {
+            node.flags = scanner.token.value;
+
+            scanner.next();
+            readSC();
         }
@@ -686,36 +814,14 @@ }
 
-function getAttrselector() {
-    expectAny('Attribute selector (=, ~=, ^=, $=, *=, |=)',
-        TokenType.EqualsSign,        // =
-        TokenType.Tilde,             // ~=
-        TokenType.CircumflexAccent,  // ^=
-        TokenType.DollarSign,        // $=
-        TokenType.Asterisk,          // *=
-        TokenType.VerticalLine       // |=
-    );
-
-    var startPos = pos;
-    var name;
-
-    if (tokens[pos].type === TokenType.EqualsSign) {
-        name = '=';
-        pos++;
-    } else {
-        name = tokens[pos].value + '=';
-        pos++;
-        eat(TokenType.EqualsSign);
-    }
-
-    return [getInfo(startPos), NodeType.AttrselectorType, name];
-}
-
 function getBraces(scope) {
-    expectAny('Parenthesis or square bracket',
-        TokenType.LeftParenthesis,
-        TokenType.LeftSquareBracket
-    );
-
     var close;
+    var child = null;
+    var node = {
+        type: 'Braces',
+        info: getInfo(),
+        open: scanner.token.value,
+        close: null,
+        sequence: new List()
+    };
 
-    if (tokens[pos].type === TokenType.LeftParenthesis) {
+    if (scanner.token.type === TokenType.LeftParenthesis) {
         close = TokenType.RightParenthesis;
@@ -726,29 +832,25 @@ } else {
 
-    var node = [
-        getInfo(pos),
-        NodeType.BracesType,
-        tokens[pos].value,
-        null
-    ];
-
     // left brace
-    pos++;
+    scanner.next();
 
+    readSC();
+
     scan:
-    while (pos < tokens.length) {
-        switch (tokens[pos].type) {
+    while (scanner.token !== null) {
+        switch (scanner.token.type) {
             case close:
-                node[3] = tokens[pos].value;
+                node.close = scanner.token.value;
                 break scan;
 
             case TokenType.Space:
-                node.push(getS());
+                child = getS();
                 break;
 
             case TokenType.Comment:
-                node.push(getComment());
+                scanner.next();
+                child = null;
                 break;
 
             case TokenType.NumberSign: // ??
-                node.push(getVhash());
+                child = getVhash();
                 break;
@@ -758,3 +860,3 @@
             case TokenType.LeftSquareBracket:
-                node.push(getBraces(scope));
+                child = getBraces(scope);
                 break;
@@ -766,10 +868,16 @@
             case TokenType.Colon:
-                node.push(getOperator());
+                child = getOperator();
                 break;
 
             default:
-                node.push(getAny(scope));
+                child = getAny(scope);
         }
+
+        if (child !== null) {
+            node.sequence.insert(List.createItem(child));
+        }
     }
 
+    removeTrailingSpaces(node.sequence);
+
     // right brace
@@ -783,25 +891,24 @@ eat(close);
 function getClass() {
-    var startPos = pos;
+    var info = getInfo();
 
     eat(TokenType.FullStop);
 
-    return [
-        getInfo(startPos),
-        NodeType.ClassType,
-        getIdentifier()
-    ];
+    return {
+        type: 'Class',
+        info: info,
+        name: readIdent(false)
+    };
 }
 
 // '#' ident
-// FIXME: shash node should has structure like other ident's (['shash', ['ident', ident]])
 function getShash() {
-    var startPos = pos;
+    var info = getInfo();
 
     eat(TokenType.NumberSign);
 
-    return [
-        getInfo(startPos),
-        NodeType.ShashType,
-        readIdent()
-    ];
+    return {
+        type: 'Id',
+        info: info,
+        name: readIdent(false)
+    };
 }
@@ -811,11 +918,16 @@
 function getCombinator() {
-    var info = getInfo(pos);
+    var info = getInfo();
     var combinator;
 
-    switch (tokens[pos].type) {
+    switch (scanner.token.type) {
+        case TokenType.Space:
+            combinator = ' ';
+            scanner.next();
+            break;
+
         case TokenType.PlusSign:
         case TokenType.GreaterThanSign:
         case TokenType.Tilde:
-            combinator = tokens[pos].value;
-            pos++;
+            combinator = scanner.token.value;
+            scanner.next();
             break;
@@ -825,3 +937,3 @@
             combinator = '/deep/';
-            pos++;
+            scanner.next();
 
@@ -837,3 +949,7 @@ expectIdentifier('deep', true);
 
-    return [info, NodeType.CombinatorType, combinator];
+    return {
+        type: 'Combinator',
+        info: info,
+        name: combinator
+    };
 }
@@ -843,3 +959,4 @@
 function getComment() {
-    var value = tokens[pos].value;
+    var info = getInfo();
+    var value = scanner.token.value;
     var len = value.length;
@@ -851,3 +968,9 @@
 
-    return [getInfo(pos++), NodeType.CommentType, value.substring(2, len)];
+    scanner.next();
+
+    return {
+        type: 'Comment',
+        info: info,
+        value: value.substring(2, len)
+    };
 }
@@ -857,4 +980,4 @@
 function readUnit() {
-    if (pos < tokens.length && tokens[pos].type === TokenType.Identifier) {
-        var unit = tokens[pos].value;
+    if (scanner.token !== null && scanner.token.type === TokenType.Identifier) {
+        var unit = scanner.token.value;
         var backSlashPos = unit.indexOf('\\');
@@ -864,3 +987,3 @@
         if (backSlashPos === -1) {
-            pos++;
+            scanner.next();
             return unit;
@@ -870,5 +993,5 @@ }
         // patch token
-        tokens[pos].value = unit.substr(backSlashPos);
-        tokens[pos].offset += backSlashPos;
-        tokens[pos].column += backSlashPos;
+        scanner.token.value = unit.substr(backSlashPos);
+        scanner.token.offset += backSlashPos;
+        scanner.token.column += backSlashPos;
 
@@ -883,46 +1006,40 @@ // return unit w/o backslash part
 // number ident
-function getDimension(startPos, number) {
-    return [
-        getInfo(startPos || pos),
-        NodeType.DimensionType,
-        number || getNumber(),
-        [getInfo(pos), NodeType.IdentType, readUnit()]
-    ];
+function getDimension(number) {
+    return {
+        type: 'Dimension',
+        info: getInfo(),
+        value: number || readNumber(),
+        unit: readUnit()
+    };
 }
 
-// expression '(' raw ')'
-function getOldIEExpression(startPos, ident) {
-    var raw = '';
-    var balance = 0;
-    var startPos = pos;
-    var ident = getIdentifier();
+// number "%"
+function tryGetPercentage() {
+    var number = tryGetNumber();
 
-    if (ident[2].toLowerCase() !== 'expression') {
-        pos--;
-        parseError('`expression` is expected');
+    if (number && scanner.token !== null && scanner.token.type === TokenType.PercentSign) {
+        return getPercentage(number);
     }
 
-    eat(TokenType.LeftParenthesis);
+    return null;
+}
 
-    while (pos < tokens.length) {
-        if (tokens[pos].type === TokenType.RightParenthesis) {
-            if (balance === 0) {
-                break;
-            }
+function getPercentage(number) {
+    var info;
 
-            balance--;
-        } else if (tokens[pos].type === TokenType.LeftParenthesis) {
-            balance++;
-        }
-
-        raw += tokens[pos++].value;
+    if (!number) {
+        info = getInfo();
+        number = readNumber();
+    } else {
+        info = number.info;
+        number = number.value;
     }
 
-    eat(TokenType.RightParenthesis);
+    eat(TokenType.PercentSign);
 
-    return [
-        getInfo(startPos),
-        NodeType.FunctionExpressionType,
-        raw
-    ];
+    return {
+        type: 'Percentage',
+        info: info,
+        value: number
+    };
 }
@@ -932,48 +1049,46 @@
 // not '(' <simpleSelector>* ')'
-function getFunction(scope) {
-    var body = getFunctionBody;
+function getFunction(scope, ident) {
+    var defaultArguments = getFunctionArguments;
 
+    if (!ident) {
+        ident = getIdentifier(false);
+    }
+
     // parse special functions
-    if (pos + 1 < tokens.length && tokens[pos].type === TokenType.Identifier) {
-        var name = tokens[pos].value.toLowerCase();
+    var name = ident.name.toLowerCase();
 
-        if (tokens[pos + 1].type === TokenType.LeftParenthesis) {
-            if (specialFunctions.hasOwnProperty(scope)) {
-                if (specialFunctions[scope].hasOwnProperty(name)) {
-                    return specialFunctions[scope][name](scope);
-                }
-            }
+    if (specialFunctions.hasOwnProperty(scope)) {
+        if (specialFunctions[scope].hasOwnProperty(name)) {
+            return specialFunctions[scope][name](scope, ident);
         }
     }
 
-    return getFunctionInternal(body, scope);
+    return getFunctionInternal(defaultArguments, scope, ident);
 }
 
-function getNotFunction(scope) {
-    return getFunctionInternal(getNotFunctionBody, scope);
-}
+function getFunctionInternal(functionArgumentsReader, scope, ident) {
+    var args;
 
-function getVarFunction(scope) {
-    return getFunctionInternal(getVarFunctionBody, scope);
-}
-
-function getFunctionInternal(functionBodyReader, scope) {
-    var startPos = pos;
-    var ident = getIdentifier();
-
     eat(TokenType.LeftParenthesis);
-
-    var body = functionBodyReader(scope);
-
+    args = functionArgumentsReader(scope);
     eat(TokenType.RightParenthesis);
 
-    return [getInfo(startPos), NodeType.FunctionType, ident, body];
+    return {
+        type: scope === SCOPE_SELECTOR ? 'FunctionalPseudo' : 'Function',
+        info: ident.info,
+        name: ident.name,
+        arguments: args
+    };
 }
 
-function getFunctionBody(scope) {
-    var node = [getInfo(pos), NodeType.FunctionBodyType];
+function getFunctionArguments(scope) {
+    var args = new List();
+    var argument = null;
+    var child = null;
 
+    readSC();
+
     scan:
-    while (pos < tokens.length) {
-        switch (tokens[pos].type) {
+    while (scanner.token !== null) {
+        switch (scanner.token.type) {
             case TokenType.RightParenthesis:
@@ -983,11 +1098,12 @@ break scan;
             case TokenType.Space:
-                node.push(getS());
+                child = getS();
                 break;
 
-            case TokenType.Comment:
-                node.push(getComment());
+            case TokenType.Comment: // ignore comments
+                scanner.next();
+                child = null;
                 break;
 
             case TokenType.NumberSign: // TODO: not sure it should be here
-                node.push(getVhash());
+                child = getVhash();
                 break;
@@ -997,28 +1113,55 @@
             case TokenType.LeftSquareBracket:
-                node.push(getBraces(scope));
+                child = getBraces(scope);
                 break;
 
+            case TokenType.Comma:
+                removeTrailingSpaces(argument.sequence);
+                scanner.next();
+                readSC();
+                argument = null;
+                child = null;
+                break;
+
             case TokenType.Solidus:
             case TokenType.Asterisk:
-            case TokenType.Comma:
             case TokenType.Colon:
             case TokenType.EqualsSign:
-                node.push(getOperator());
+                child = getOperator();
                 break;
 
             default:
-                node.push(getAny(scope));
+                child = getAny(scope);
         }
+
+        if (argument === null) {
+            argument = {
+                type: 'Argument',
+                sequence: new List()
+            };
+            args.insert(List.createItem(argument));
+        }
+
+        if (child !== null) {
+            argument.sequence.insert(List.createItem(child));
+        }
     }
 
-    return node;
+    if (argument !== null) {
+        removeTrailingSpaces(argument.sequence);
+    }
+
+    return args;
 }
 
-function getNotFunctionBody() {
-    var node = [getInfo(pos), NodeType.FunctionBodyType];
+function getVarFunction(scope, ident) {
+    return getFunctionInternal(getVarFunctionArguments, scope, ident);
+}
+
+function getNotFunctionArguments() {
+    var args = new List();
     var wasSelector = false;
 
     scan:
-    while (pos < tokens.length) {
-        switch (tokens[pos].type) {
+    while (scanner.token !== null) {
+        switch (scanner.token.type) {
             case TokenType.RightParenthesis:
@@ -1037,6 +1180,3 @@ if (!wasSelector) {
                 wasSelector = false;
-                node.push([
-                    getInfo(pos++),
-                    NodeType.DelimType
-                ]);
+                scanner.next();
                 break;
@@ -1046,52 +1186,74 @@
                 wasSelector = true;
-                node.push(getSimpleSelector(true));
+                args.insert(List.createItem(getSimpleSelector(true)));
         }
     }
 
-    return node;
+    return args;
 }
 
+function getNotFunction(scope, ident) {
+    var args;
+
+    eat(TokenType.LeftParenthesis);
+    args = getNotFunctionArguments(scope);
+    eat(TokenType.RightParenthesis);
+
+    return {
+        type: 'Negation',
+        info: ident.info,
+        // name: ident.name,  // TODO: add name?
+        sequence: args        // FIXME: -> arguments?
+    };
+}
+
 // var '(' ident (',' <declaration-value>)? ')'
-function getVarFunctionBody() {
-    var node = [getInfo(pos), NodeType.FunctionBodyType];
+function getVarFunctionArguments() { // TODO: special type Variable?
+    var args = new List();
 
-    readSC(node);
-    node.push(getIdentifier(true));
-    readSC(node);
+    readSC();
 
-    if (pos < tokens.length && tokens[pos].type === TokenType.Comma) {
-        node.push(
-            getOperator(),
-            getValue(true)
-        );
-        readSC(node);
+    args.insert(List.createItem({
+        type: 'Argument',
+        sequence: new List([getIdentifier(true)])
+    }));
+
+    readSC();
+
+    if (scanner.token !== null && scanner.token.type === TokenType.Comma) {
+        eat(TokenType.Comma);
+        readSC();
+
+        args.insert(List.createItem({
+            type: 'Argument',
+            sequence: new List([getValue(true)])
+        }));
+
+        readSC();
     }
 
-    return node;
+    return args;
 }
 
 // url '(' ws* (string | raw) ws* ')'
-function getUri() {
-    var startPos = pos;
-    var node = [getInfo(startPos), NodeType.UriType];
-    var ident = getIdentifier();
+function getUri(scope, ident) {
+    var node = {
+        type: 'Url',
+        info: ident.info,
+        // name: ident.name,
+        value: null
+    };
 
-    if (ident[2].toLowerCase() !== 'url') {
-        pos--;
-        parseError('`url` is expected');
-    }
-
     eat(TokenType.LeftParenthesis); // (
 
-    readSC(node);
+    readSC();
 
-    if (tokens[pos].type === TokenType.String) {
-        node.push(getString());
-        readSC(node);
+    if (scanner.token.type === TokenType.String) {
+        node.value = getString();
+        readSC();
     } else {
-        var rawStart = pos;
+        var rawInfo = getInfo();
         var raw = '';
 
-        while (pos < tokens.length) {
-            var type = tokens[pos].type;
+        for (; scanner.token !== null; scanner.next()) {
+            var type = scanner.token.type;
 
@@ -1104,12 +1266,12 @@ if (type === TokenType.Space ||
 
-            raw += tokens[pos++].value;
+            raw += scanner.token.value;
         }
 
-        node.push([
-            getInfo(rawStart),
-            NodeType.RawType,
-            raw
-        ]);
+        node.value = {
+            type: 'Raw',
+            info: rawInfo,
+            value: raw
+        };
 
-        readSC(node);
+        readSC();
     }
@@ -1122,12 +1284,49 @@
 
-function getUnicodeRange(tryNext) {
+// expression '(' raw ')'
+function getOldIEExpression(scope, ident) {
+    var balance = 0;
+    var raw = '';
+
+    eat(TokenType.LeftParenthesis);
+
+    for (; scanner.token !== null; scanner.next()) {
+        if (scanner.token.type === TokenType.RightParenthesis) {
+            if (balance === 0) {
+                break;
+            }
+
+            balance--;
+        } else if (scanner.token.type === TokenType.LeftParenthesis) {
+            balance++;
+        }
+
+        raw += scanner.token.value;
+    }
+
+    eat(TokenType.RightParenthesis);
+
+    return {
+        type: 'Function',
+        info: ident.info,
+        name: ident.name,
+        arguments: new List([{
+            type: 'Argument',
+            sequence: new List([{
+                type: 'Raw',
+                value: raw
+            }])
+        }])
+    };
+}
+
+function readUnicodeRange(tryNext) {
     var hex = '';
 
-    for (; pos < tokens.length; pos++) {
-        if (tokens[pos].type !== TokenType.DecimalNumber &&
-            tokens[pos].type !== TokenType.Identifier) {
+    for (; scanner.token !== null; scanner.next()) {
+        if (scanner.token.type !== TokenType.DecimalNumber &&
+            scanner.token.type !== TokenType.Identifier) {
             break;
         }
 
-        hex += tokens[pos].value;
+        hex += scanner.token.value;
     }
@@ -1141,8 +1340,8 @@
     if (tryNext) {
-        for (; hex.length < 6 && pos < tokens.length; pos++) {
-            if (tokens[pos].type !== TokenType.QuestionMark) {
+        for (; hex.length < 6 && scanner.token !== null; scanner.next()) {
+            if (scanner.token.type !== TokenType.QuestionMark) {
                 break;
             }
 
-            hex += tokens[pos].value;
+            hex += scanner.token.value;
             tryNext = false;
@@ -1154,6 +1353,7 @@ }
     if (tryNext) {
-        if (pos < tokens.length && tokens[pos].type === TokenType.HyphenMinus) {
-            pos++;
-            var next = getUnicodeRange(false);
+        if (scanner.token !== null && scanner.token.type === TokenType.HyphenMinus) {
+            scanner.next();
 
+            var next = readUnicodeRange(false);
+
             if (!next) {
@@ -1174,9 +1374,9 @@ parseError('Unexpected input');
     // optional first -
-    if (pos < tokens.length && tokens[pos].type === TokenType.HyphenMinus) {
+    if (scanner.token !== null && scanner.token.type === TokenType.HyphenMinus) {
         name = '-';
-        pos++;
+        scanner.next();
 
-        if (varAllowed && pos < tokens.length && tokens[pos].type === TokenType.HyphenMinus) {
+        if (varAllowed && scanner.token !== null && scanner.token.type === TokenType.HyphenMinus) {
             name = '--';
-            pos++;
+            scanner.next();
         }
@@ -1190,8 +1390,9 @@ }
 
-    if (pos < tokens.length) {
-        name += tokens[pos].value;
-        pos++;
+    if (scanner.token !== null) {
+        name += scanner.token.value;
+        scanner.next();
 
-        for (; pos < tokens.length; pos++) {
-            var type = tokens[pos].type;
+        for (; scanner.token !== null; scanner.next()) {
+            var type = scanner.token.type;
+
             if (type !== TokenType.LowLine &&
@@ -1204,3 +1405,3 @@ type !== TokenType.Identifier &&
 
-            name += tokens[pos].value;
+            name += scanner.token.value;
         }
@@ -1213,33 +1414,31 @@ }
 function getNamespacedIdentifier(checkColon) {
-    if (pos >= tokens.length) {
+    if (scanner.token === null) {
         parseError('Unexpected end of input');
     }
 
-    var info = getInfo(pos);
+    var info = getInfo();
     var name;
 
-    if (tokens[pos].type === TokenType.Asterisk) {
+    if (scanner.token.type === TokenType.Asterisk) {
         checkColon = false;
         name = '*';
-        pos++;
+        scanner.next();
     } else {
-        name = readIdent();
+        name = readIdent(false);
     }
 
-    if (pos < tokens.length) {
-        if (tokens[pos].type === TokenType.VerticalLine &&
-            pos + 1 < tokens.length &&
-            tokens[pos + 1].type !== TokenType.EqualsSign) {
+    if (scanner.token !== null) {
+        if (scanner.token.type === TokenType.VerticalLine &&
+            scanner.lookupType(1, TokenType.EqualsSign) === false) {
             name += '|';
-            pos++;
 
-            if (pos < tokens.length) {
-                if (tokens[pos].type === TokenType.HyphenMinus ||
-                    tokens[pos].type === TokenType.Identifier ||
-                    tokens[pos].type === TokenType.LowLine) {
-                    name += readIdent();
-                } else if (tokens[pos].type === TokenType.Asterisk) {
+            if (scanner.next() !== null) {
+                if (scanner.token.type === TokenType.HyphenMinus ||
+                    scanner.token.type === TokenType.Identifier ||
+                    scanner.token.type === TokenType.LowLine) {
+                    name += readIdent(false);
+                } else if (scanner.token.type === TokenType.Asterisk) {
                     checkColon = false;
                     name += '*';
-                    pos++;
+                    scanner.next();
                 }
@@ -1250,27 +1449,43 @@ }
 
-    if (checkColon && pos < tokens.length && tokens[pos].type === TokenType.Colon) {
-        pos++;
-        name += ':' + readIdent();
+    if (checkColon && scanner.token !== null && scanner.token.type === TokenType.Colon) {
+        scanner.next();
+        name += ':' + readIdent(false);
     }
 
-    return [
-        info,
-        NodeType.IdentType,
-        name
-    ];
+    return {
+        type: 'Identifier',
+        info: info,
+        name: name
+    };
 }
 
 function getIdentifier(varAllowed) {
-    return [getInfo(pos), NodeType.IdentType, readIdent(varAllowed)];
+    return {
+        type: 'Identifier',
+        info: getInfo(),
+        name: readIdent(varAllowed)
+    };
 }
 
 // ! ws* important
-function getImportant() {
+function getImportant() { // TODO?
+    // var info = getInfo();
+
     eat(TokenType.ExclamationMark);
 
-    var node = readSC([getInfo(pos - 1), NodeType.ImportantType]);
+    readSC();
 
-    expectIdentifier('important', true);
+    // return {
+    //     type: 'Identifier',
+    //     info: info,
+    //     name: readIdent(false)
+    // };
 
-    return node;
+    expectIdentifier('important');
+
+    readIdent(false);
+
+    // should return identifier in future for original source restoring as is
+    // returns true for now since it's fit to optimizer purposes
+    return true;
 }
@@ -1285,12 +1500,13 @@
 
-    var startPos = pos;
-    var value = tokens[pos].value;
+    var info = getInfo();
+    var value = scanner.token.value;
     var cmpValue;
 
-    if (tokens[pos].type === TokenType.DecimalNumber) {
-        if (pos + 1 < tokens.length &&
-            tokens[pos + 1].type === TokenType.Identifier &&
-            tokens[pos + 1].value.toLowerCase() === 'n') {
-            value += tokens[pos + 1].value;
-            pos++;
+    if (scanner.token.type === TokenType.DecimalNumber) {
+        var next = scanner.lookup(1);
+        if (next !== null &&
+            next.type === TokenType.Identifier &&
+            next.value.toLowerCase() === 'n') {
+            value += next.value;
+            scanner.next();
         }
@@ -1304,16 +1520,29 @@ } else {
 
-    pos++;
+    scanner.next();
 
-    return [
-        getInfo(startPos),
-        NodeType.NthType,
-        value
-    ];
+    return {
+        type: 'Nth',
+        info: info,
+        value: value
+    };
 }
 
 function getNthSelector() {
+    var info = getInfo();
+    var sequence = new List();
+    var node;
+    var child = null;
+
     eat(TokenType.Colon);
     expectIdentifier('nth', false);
 
-    var node = [getInfo(pos - 1), NodeType.NthselectorType, getIdentifier()];
+    node = {
+        type: 'FunctionalPseudo',
+        info: info,
+        name: readIdent(false),
+        arguments: new List([{
+            type: 'Argument',
+            sequence: sequence
+        }])
+    };
 
@@ -1323,4 +1552,4 @@ eat(TokenType.LeftParenthesis);
     scan:
-    while (pos < tokens.length) {
-        switch (tokens[pos].type) {
+    while (scanner.token !== null) {
+        switch (scanner.token.type) {
             case TokenType.RightParenthesis:
@@ -1330,7 +1559,5 @@ break scan;
             case TokenType.Space:
-                node.push(getS());
-                break;
-
             case TokenType.Comment:
-                node.push(getComment());
+                scanner.next();
+                child = null;
                 break;
@@ -1340,8 +1567,12 @@
             case TokenType.PlusSign:
-                node.push(getUnary());
+                child = getOperator();
                 break;
 
             default:
-                node.push(getNth());
+                child = getNth();
         }
+
+        if (child !== null) {
+            sequence.insert(List.createItem(child));
+        }
     }
@@ -1354,33 +1585,35 @@
 
-function tryGetNumber() {
-    var startPos = pos;
+function readNumber() {
     var wasDigits = false;
     var number = '';
-    var i = pos;
+    var offset = 0;
 
-    if (i < tokens.length && tokens[i].type === TokenType.HyphenMinus) {
+    if (scanner.lookupType(offset, TokenType.HyphenMinus)) {
         number = '-';
-        i++;
+        offset++;
     }
 
-    if (i < tokens.length && tokens[i].type === TokenType.DecimalNumber) {
+    if (scanner.lookupType(offset, TokenType.DecimalNumber)) {
         wasDigits = true;
-        number += tokens[i].value;
-        i++;
+        number += scanner.lookup(offset).value;
+        offset++;
     }
 
-    if (i < tokens.length && tokens[i].type === TokenType.FullStop) {
+    if (scanner.lookupType(offset, TokenType.FullStop)) {
         number += '.';
-        i++;
+        offset++;
     }
 
-    if (i < tokens.length && tokens[i].type === TokenType.DecimalNumber) {
+    if (scanner.lookupType(offset, TokenType.DecimalNumber)) {
         wasDigits = true;
-        number += tokens[i].value;
-        i++;
+        number += scanner.lookup(offset).value;
+        offset++;
     }
 
     if (wasDigits) {
-        pos = i;
-        return [getInfo(startPos), NodeType.NumberType, number];
+        while (offset--) {
+            scanner.next();
+        }
+
+        return number;
     }
@@ -1391,68 +1624,49 @@
 
-function getNumber() {
-    var number = tryGetNumber();
+function tryGetNumber() {
+    var info = getInfo();
+    var number = readNumber();
 
-    if (!number) {
-        parseError('Wrong number');
+    if (number !== null) {
+        return {
+            type: 'Number',
+            info: info,
+            value: number
+        };
     }
 
-    return number;
+    return null;
 }
 
-// '/' | '*' | ',' | ':' | '='
+// '/' | '*' | ',' | ':' | '=' | '+' | '-'
 // TODO: remove '=' since it's wrong operator, but theat as operator
 // to make old things like `filter: alpha(opacity=0)` works
 function getOperator() {
-    expectAny('Operator',
-        TokenType.Solidus,
-        TokenType.Asterisk,
-        TokenType.Comma,
-        TokenType.Colon,
-        TokenType.EqualsSign
-    );
+    var node = {
+        type: 'Operator',
+        info: getInfo(),
+        value: scanner.token.value
+    };
 
-    return [getInfo(pos), NodeType.OperatorType, tokens[pos++].value];
-}
+    scanner.next();
 
-// node: Percentage
-function tryGetPercentage() {
-    var startPos = pos;
-    var number = tryGetNumber();
-
-    if (!number) {
-        return null;
-    }
-
-    if (pos >= tokens.length || tokens[pos].type !== TokenType.PercentSign) {
-        return null;
-    }
-
-    return getPercentage(startPos, number);
+    return node;
 }
 
-function getPercentage(startPos, number) {
-    if (!startPos) {
-        startPos = pos;
-    }
+function getFilterValue() { // TODO
+    var progid;
+    var node = {
+        type: 'Value',
+        info: getInfo(),
+        important: false,
+        sequence: new List()
+    };
 
-    if (!number) {
-        number = getNumber();
+    while (progid = checkProgid()) {
+        node.sequence.insert(List.createItem(getProgid(progid)));
     }
 
-    eat(TokenType.PercentSign);
-
-    return [getInfo(startPos), NodeType.PercentageType, number];
-}
-
-function getFilterv() {
-    var node = [getInfo(pos), NodeType.FiltervType];
-
-    while (checkProgid(pos)) {
-        node.push(getProgid());
-    }
-
     readSC(node);
 
-    if (pos < tokens.length && tokens[pos].type === TokenType.ExclamationMark) {
-        node.push(getImportant());
+    if (scanner.token !== null && scanner.token.type === TokenType.ExclamationMark) {
+        node.important = getImportant();
     }
@@ -1464,65 +1678,63 @@
 // 'progid:' ws* 'DXImageTransform.Microsoft.' ident ws* '(' .* ')'
-function checkSC(i) {
-    var start = i;
+function checkProgid() {
+    function checkSC(offset) {
+        for (var cursor; cursor = scanner.lookup(offset); offset++) {
+            if (cursor.type !== TokenType.Space &&
+                cursor.type !== TokenType.Comment) {
+                break;
+            }
+        }
 
-    while (i < tokens.length) {
-        if (tokens[i].type === TokenType.Space ||
-            tokens[i].type === TokenType.Comment) {
-            i++;
-        } else {
-            break;
-        }
+        return offset;
     }
 
-    return i - start;
-}
+    var offset = checkSC(0);
 
-function checkProgid(i) {
-    var start = i;
-
-    i += checkSC(i);
-
-    if (i + 1 >= tokens.length ||
-        tokens[i + 0].value.toLowerCase() !== 'progid' ||
-        tokens[i + 1].type !== TokenType.Colon) {
+    if (scanner.lookup(offset + 1) === null ||
+        scanner.lookup(offset + 0).value.toLowerCase() !== 'progid' ||
+        scanner.lookup(offset + 1).type !== TokenType.Colon) {
         return false; // fail
     }
 
-    i += 2;
-    i += checkSC(i);
+    offset += 2;
+    offset = checkSC(offset);
 
-    if (i + 6 >= tokens.length ||
-        tokens[i + 0].value.toLowerCase() !== 'dximagetransform' ||
-        tokens[i + 1].type !== TokenType.FullStop ||
-        tokens[i + 2].value.toLowerCase() !== 'microsoft' ||
-        tokens[i + 3].type !== TokenType.FullStop ||
-        tokens[i + 4].type !== TokenType.Identifier) {
+    if (scanner.lookup(offset + 5) === null ||
+        scanner.lookup(offset + 0).value.toLowerCase() !== 'dximagetransform' ||
+        scanner.lookup(offset + 1).type !== TokenType.FullStop ||
+        scanner.lookup(offset + 2).value.toLowerCase() !== 'microsoft' ||
+        scanner.lookup(offset + 3).type !== TokenType.FullStop ||
+        scanner.lookup(offset + 4).type !== TokenType.Identifier) {
         return false; // fail
     }
 
-    i += 5;
-    i += checkSC(i);
+    offset += 5;
+    offset = checkSC(offset);
 
-    if (i >= tokens.length ||
-        tokens[i].type !== TokenType.LeftParenthesis) {
+    if (scanner.lookupType(offset, TokenType.LeftParenthesis) === false) {
         return false; // fail
     }
 
-    while (i < tokens.length) {
-        if (tokens[i++].type === TokenType.RightParenthesis) {
-            break;
+    for (var cursor; cursor = scanner.lookup(offset); offset++) {
+        if (cursor.type === TokenType.RightParenthesis) {
+            return cursor;
         }
     }
 
-    tokens[start].progidEnd = i;
-
-    return true;
+    return false;
 }
 
-function getProgid() {
-    var node = [getInfo(pos), NodeType.ProgidType];
-    var progidEnd = tokens[pos].progidEnd;
+function getProgid(progidEnd) {
     var value = '';
+    var node = {
+        type: 'Progid',
+        info: getInfo(),
+        value: null
+    };
 
-    if (!progidEnd && !checkProgid(pos)) {
+    if (!progidEnd) {
+        progidEnd = checkProgid();
+    }
+
+    if (!progidEnd) {
         parseError('progid is expected');
@@ -1533,13 +1745,16 @@ }
 
-    var rawStart = pos;
-    for (; pos < progidEnd; pos++) {
-        value += tokens[pos].value;
+    var rawInfo = getInfo();
+    for (; scanner.token && scanner.token !== progidEnd; scanner.next()) {
+        value += scanner.token.value;
     }
 
-    node.push([
-        getInfo(rawStart),
-        NodeType.RawType,
-        value
-    ]);
+    eat(TokenType.RightParenthesis);
+    value += ')';
 
+    node.value = {
+        type: 'Raw',
+        info: rawInfo,
+        value: value
+    };
+
     readSC(node);
@@ -1552,13 +1767,9 @@
 function getPseudo() {
-    if (pos >= tokens.length || tokens[pos].type !== TokenType.Colon) {
-        parseError('Colon is expected');
-    }
+    var next = scanner.lookup(1);
 
-    if (pos + 1 >= tokens.length) {
-        pos++;
+    if (next === null) {
+        scanner.next();
         parseError('Colon or identifier is expected');
     }
 
-    var next = tokens[pos + 1];
-
     if (next.type === TokenType.Colon) {
@@ -1578,6 +1789,12 @@ return getPseudoElement();
 function getPseudoElement() {
+    var info = getInfo();
+
     eat(TokenType.Colon);
     eat(TokenType.Colon);
 
-    return [getInfo(pos - 2), NodeType.PseudoeType, getIdentifier()];
+    return {
+        type: 'PseudoElement',
+        info: info,
+        name: readIdent(false)
+    };
 }
@@ -1587,15 +1804,14 @@
 function getPseudoClass() {
-    var startPos = pos;
-    var node = eat(TokenType.Colon) && getIdentifier();
+    var info = getInfo();
+    var ident = eat(TokenType.Colon) && getIdentifier(false);
 
-    if (pos < tokens.length && tokens[pos].type === TokenType.LeftParenthesis) {
-        pos = startPos + 1;
-        node = getFunction(SCOPE_SELECTOR);
+    if (scanner.token !== null && scanner.token.type === TokenType.LeftParenthesis) {
+        return getFunction(SCOPE_SELECTOR, ident);
     }
 
-    return [
-        getInfo(startPos),
-        NodeType.PseudocType,
-        node
-    ];
+    return {
+        type: 'PseudoClass',
+        info: info,
+        name: ident.name
+    };
 }
@@ -1605,15 +1821,26 @@
 function getS() {
-    return [getInfo(pos), NodeType.SType, tokens[pos++].value];
+    var node = {
+        type: 'Space'
+        // value: scanner.token.value
+    };
+
+    scanner.next();
+
+    return node;
 }
 
-function readSC(node) {
+function readSC() {
+    // var nodes = [];
+
     scan:
-    while (pos < tokens.length) {
-        switch (tokens[pos].type) {
+    while (scanner.token !== null) {
+        switch (scanner.token.type) {
             case TokenType.Space:
-                node.push(getS());
+                scanner.next();
+                // nodes.push(getS());
                 break;
 
             case TokenType.Comment:
-                node.push(getComment());
+                scanner.next();
+                // nodes.push(getComment());
                 break;
@@ -1626,3 +1853,5 @@
 
-    return node;
+    return null;
+
+    // return nodes.length ? new List(nodes) : null;
 }
@@ -1632,25 +1861,18 @@
 function getString() {
-    return [getInfo(pos), NodeType.StringType, tokens[pos++].value];
-}
+    var node = {
+        type: 'String',
+        info: getInfo(),
+        value: scanner.token.value
+    };
 
-// '+' | '-'
-function getUnary() {
-    expectAny('Unary operator',
-        TokenType.HyphenMinus,
-        TokenType.PlusSign
-    );
+    scanner.next();
 
-    return [getInfo(pos), NodeType.UnaryType, tokens[pos++].value];
+    return node;
 }
 
-// '//' ...
-// TODO: remove it as wrong thing
-function getUnknown() {
-    eat(TokenType.Unknown);
-
-    return [getInfo(pos - 1), NodeType.UnknownType, tokens[pos - 1].value];
-}
-
 // # ident
 function getVhash() {
+    var info = getInfo();
+    var value;
+
     eat(TokenType.NumberSign);
@@ -1663,61 +1885,43 @@
 
-    var name = tokens[pos].value;
+    value = scanner.token.value;
 
-    if (tokens[pos++].type === TokenType.DecimalNumber) {
-        if (pos < tokens.length && tokens[pos].type === TokenType.Identifier) {
-            name += tokens[pos++].value;
-        }
+    if (scanner.token.type === TokenType.DecimalNumber &&
+        scanner.lookupType(1, TokenType.Identifier)) {
+        scanner.next();
+        value += scanner.token.value;
     }
 
-    return [getInfo(pos - 1), NodeType.VhashType, name];
+    scanner.next();
+
+    return {
+        type: 'Hash',
+        info: info,
+        value: value
+    };
 }
 
-module.exports = function parse(source, context, options) {
+module.exports = function parse(source, options) {
     var ast;
 
-    options = options || {};
-
-    if (options === true) {
-        options = {
-            positions: true,
-            needInfo: true
-        };
+    if (!options || typeof options !== 'object') {
+        options = {};
     }
 
-    if ('positions' in options) {
-        needPositions = options.positions || false;
-    } else {
-        // deprecated option but using for backward capability
-        needPositions = options.needPositions || false;
-    }
-
+    var context = options.context || 'stylesheet';
+    needPositions = Boolean(options.positions);
     filename = options.filename || '<unknown>';
-    context = context || 'stylesheet';
-    pos = 0;
 
-    tokens = tokenize(source, blockMode.hasOwnProperty(context), options.line, options.column);
-
-    if (tokens.length) {
-        ast = rules[context]();
+    if (!initialContext.hasOwnProperty(context)) {
+        throw new Error('Unknown context `' + context + '`');
     }
 
-    tokens = null; // drop tokens
+    scanner = new Scanner(source, blockMode.hasOwnProperty(context), options.line, options.column);
+    scanner.next();
+    ast = initialContext[context]();
 
-    if (!ast) {
-        switch (context) {
-            case 'stylesheet':
-                ast = [{}, context];
-                break;
-            // case 'declarations':
-            //     ast = [{}, 'block'];
-            //     break;
-        }
-    }
+    scanner = null;
 
-    if (ast && !options.needInfo) {
-        ast = cleanInfo(ast);
-    }
-
-    // console.log(require('../utils/stringify.js')(require('../utils/cleanInfo.js')(ast), true));
+    // console.log(JSON.stringify(ast, null, 4));
+    // console.log(require('../utils/stringify.js')(ast, true));
     return ast;
 };

lib/utils/translate.js

@@ -1,197 +0,168 @@
-var useInfo;
-var buffer;
-var typeHandlers = {
-    unary: simple,
-    nth: simple,
-    combinator: simple,
-    ident: simple,
-    number: simple,
-    s: simple,
-    string: simple,
-    attrselector: simple,
-    operator: simple,
-    raw: simple,
-    unknown: simple,
-    attribFlags: simple,
+function each(list) {
+    if (list.head === null) {
+        return '';
+    }
 
-    simpleselector: composite,
-    dimension: composite,
-    selector: composite,
-    property: composite,
-    value: composite,
-    filterv: composite,
-    progid: composite,
-    ruleset: composite,
-    atruleb: composite,
-    atrulerq: composite,
-    atrulers: composite,
-    stylesheet: composite,
-
-    percentage: percentage,
-    comment: comment,
-    clazz: clazz,
-    atkeyword: atkeyword,
-    shash: shash,
-    vhash: vhash,
-    attrib: attrib,
-    important: important,
-    nthselector: nthselector,
-    funktion: funktion,
-    declaration: declaration,
-    filter: filter,
-    block: block,
-    braces: braces,
-    atrules: atrules,
-    atruler: atruler,
-    pseudoe: pseudoe,
-    pseudoc: pseudoc,
-    uri: uri,
-    functionExpression: functionExpression,
-
-    decldelim: function() {
-        buffer.push(';');
-    },
-    delim: function() {
-        buffer.push(',');
+    if (list.head === list.tail) {
+        return translate(list.head.data);
     }
-};
 
-function simple(token) {
-    buffer.push(token[useInfo + 1]);
+    return list.map(translate).join('');
 }
 
-function composite(token) {
-    for (var i = useInfo + 1; i < token.length; i++) {
-        translate(token[i]);
+function eachDelim(list, delimeter) {
+    if (list.head === null) {
+        return '';
     }
-}
 
-function compositeFrom(token, i) {
-    for (; i < token.length; i++) {
-        translate(token[i]);
+    if (list.head === list.tail) {
+        return translate(list.head.data);
     }
-}
 
-function percentage(token) {
-    translate(token[useInfo + 1]);
-    buffer.push('%');
+    return list.map(translate).join(delimeter);
 }
 
-function comment(token) {
-    buffer.push('/*', token[useInfo + 1], '*/');
-}
+function translate(node) {
+    switch (node.type) {
+        case 'StyleSheet':
+            return each(node.rules);
 
-function clazz(token) {
-    buffer.push('.');
-    translate(token[useInfo + 1]);
-}
+        case 'Atrule':
+            var result = '@' + node.name;
 
-function atkeyword(token) {
-    buffer.push('@');
-    translate(token[useInfo + 1]);
-}
+            if (node.expression && !node.expression.sequence.isEmpty()) {
+                result += ' ' + translate(node.expression);
+            }
 
-function shash(token) {
-    buffer.push('#', token[useInfo + 1]);
-}
+            if (node.block) {
+                return result + '{' + translate(node.block) + '}';
+            } else {
+                return result + ';';
+            }
 
-function vhash(token) {
-    buffer.push('#', token[useInfo + 1]);
-}
+        case 'Ruleset':
+            return translate(node.selector) + '{' + translate(node.block) + '}';
 
-function attrib(token) {
-    buffer.push('[');
-    composite(token);
-    buffer.push(']');
-}
+        case 'Selector':
+            return eachDelim(node.selectors, ',');
 
-function important(token) {
-    buffer.push('!');
-    composite(token);
-    buffer.push('important');
-}
+        case 'SimpleSelector':
+            return node.sequence.map(function(node) {
+                // add extra spaces around /deep/ combinator since comment beginning/ending may to be produced
+                if (node.type === 'Combinator' && node.name === '/deep/') {
+                    return ' ' + translate(node) + ' ';
+                }
 
-function nthselector(token) {
-    buffer.push(':');
-    simple(token[useInfo + 1]);
-    buffer.push('(');
-    compositeFrom(token, useInfo + 2);
-    buffer.push(')');
-}
+                return translate(node);
+            }).join('');
 
-function funktion(token) {
-    simple(token[useInfo + 1]);
-    buffer.push('(');
-    composite(token[useInfo + 2]);
-    buffer.push(')');
-}
+        case 'Declaration':
+            return translate(node.property) + ':' + translate(node.value);
 
-function declaration(token) {
-    translate(token[useInfo + 1]);
-    buffer.push(':');
-    translate(token[useInfo + 2]);
-}
+        case 'Property':
+            return node.name;
 
-function filter(token) {
-    translate(token[useInfo + 1]);
-    buffer.push(':');
-    translate(token[useInfo + 2]);
-}
+        case 'Value':
+            return node.important
+                ? each(node.sequence) + '!important'
+                : each(node.sequence);
 
-function block(token) {
-    buffer.push('{');
-    composite(token);
-    buffer.push('}');
-}
+        case 'Attribute':
+            var result = translate(node.name);
 
-function braces(token) {
-    buffer.push(token[useInfo + 1]);
-    compositeFrom(token, useInfo + 3);
-    buffer.push(token[useInfo + 2]);
-}
+            if (node.operator !== null) {
+                result += node.operator;
 
-function atrules(token) {
-    composite(token);
-    buffer.push(';');
-}
+                if (node.value !== null) {
+                    result += translate(node.value);
 
-function atruler(token) {
-    translate(token[useInfo + 1]);
-    translate(token[useInfo + 2]);
-    buffer.push('{');
-    translate(token[useInfo + 3]);
-    buffer.push('}');
-}
+                    if (node.flags !== null) {
+                        result += (node.value.type !== 'String' ? ' ' : '') + node.flags;
+                    }
+                }
+            }
 
-function pseudoe(token) {
-    buffer.push('::');
-    translate(token[useInfo + 1]);
-}
+            return '[' + result + ']';
 
-function pseudoc(token) {
-    buffer.push(':');
-    translate(token[useInfo + 1]);
-}
+        case 'FunctionalPseudo':
+            return ':' + node.name + '(' + eachDelim(node.arguments, ',') + ')';
 
-function uri(token) {
-    buffer.push('url(');
-    composite(token);
-    buffer.push(')');
-}
+        case 'Function':
+            return node.name + '(' + eachDelim(node.arguments, ',') + ')';
 
-function functionExpression(token) {
-    buffer.push('expression(', token[useInfo + 1], ')');
-}
+        case 'Block':
+            return eachDelim(node.declarations, ';');
 
-function translate(token) {
-    typeHandlers[token[useInfo]](token);
-}
+        case 'Negation':
+            return ':not(' + eachDelim(node.sequence, ',') + ')';
 
-module.exports = function(tree, hasInfo) {
-    useInfo = hasInfo ? 1 : 0;
-    buffer = [];
+        case 'Braces':
+            return node.open + each(node.sequence) + node.close;
 
-    translate(tree);
+        case 'Argument':
+        case 'AtruleExpression':
+            return each(node.sequence);
 
-    return buffer.join('');
-};
+        case 'Url':
+            return 'url(' + translate(node.value) + ')';
+
+        case 'Progid':
+            return translate(node.value);
+
+        case 'Combinator':
+            return node.name;
+
+        case 'Identifier':
+            return node.name;
+
+        case 'PseudoClass':
+            return ':' + node.name;
+
+        case 'PseudoElement':
+            return '::' + node.name;
+
+        case 'Class':
+            return '.' + node.name;
+
+        case 'Id':
+            return '#' + node.name;
+
+        case 'Hash':
+            return '#' + node.value;
+
+        case 'Dimension':
+            return node.value + node.unit;
+
+        case 'Nth':
+            return node.value;
+
+        case 'Number':
+            return node.value;
+
+        case 'String':
+            return node.value;
+
+        case 'Operator':
+            return node.value;
+
+        case 'Raw':
+            return node.value;
+
+        case 'Unknown':
+            return node.value;
+
+        case 'Percentage':
+            return node.value + '%';
+
+        case 'Space':
+            return ' ';
+
+        case 'Comment':
+            return '/*' + node.value + '*/';
+
+        default:
+            throw new Error('Unknown node type: ' + node.type);
+    }
+}
+
+module.exports = translate;

package.json

 {
   "name": "csso",
-  "version": "1.8.1",
+  "version": "2.0.0",
   "description": "CSSO (CSS Optimizer) is a CSS minifier with structural optimisations",
@@ -5,0 +5,0 @@ "keywords": [

README.md

@@ -49,7 +49,7 @@ [![NPM version](https://img.shields.io/npm/v/csso.svg)](https://www.npmjs.com/package/csso)
 ```
-> csso in.css out.css
-
 > csso in.css
 ...output result in stdout...
 
+> csso in.css --output out.css
+
 > echo '.test { color: #ff0000; }' | csso
@@ -59,10 +59,2 @@ .test{color:red}
 > cat source1.css source2.css | csso | gzip -9 -c > production.css.gz
-
-> echo '.test { color: #ff0000 }' | csso --stat >/dev/null
-File:       <stdin>
-Original:   25 bytes
-Compressed: 16 bytes (64.00%)
-Saving:     9 bytes (36.00%)
-Time:       12 ms
-Memory:     0.346 MB
 ```
@@ -115,3 +107,3 @@
 
-> `ids` and `classes` comparison is case sensetive, `tags` – is not.
+> `ids` and `classes` names are case sensitive, `tags` – is not.
 
@@ -188,14 +180,6 @@ Input CSS:
 
-var compressedCss = csso.minify('.test { color: #ff0000; }');
+var compressedCss = csso.minify('.test { color: #ff0000; }').css;
 
 console.log(compressedCss);
 // .test{color:red}
-
-
-// there are some options you can pass
-var compressedWithOptions = csso.minify('.test { color: #ff0000; }', {
-    restructure: false,   // don't change css structure, i.e. don't merge declarations, rulesets etc
-    debug: true           // show additional debug information:
-                          // true or number from 1 to 3 (greater number - more details)
-});
 ```
@@ -207,4 +191,4 @@
 var ast = csso.parse('.test { color: #ff0000; }');
-var compressedAst = csso.compress(ast);
-var compressedCss = csso.translate(compressedAst, true);
+var compressResult = csso.compress(ast);
+var compressedCss = csso.translate(compressResult.ast);
 
@@ -231,77 +215,168 @@ console.log(compressedCss);
 
-### Debugging
+#### minify(source[, options])
 
+Minify `source` CSS passed as `String`.
+
+Options:
+
+- sourceMap `Boolean` - generate source map if `true`
+- filename `String` - filename of input, uses for source map
+- debug `Boolean` - output debug information to `stderr`
+- other options are the same as for `compress()`
+
+Returns an object with properties:
+
+- css `String` – resulting CSS
+- map `Object` – instance of `SourceMapGenerator` or `null`
+
+```js
+var result = csso.minify('.test { color: #ff0000; }', {
+    restructure: false,   // don't change CSS structure, i.e. don't merge declarations, rulesets etc
+    debug: true           // show additional debug information:
+                          // true or number from 1 to 3 (greater number - more details)
+});
+
+console.log(result.css);
+// > .test{color:red}
 ```
-> echo '.test { color: green; color: #ff0000 } .foo { color: red }' | csso --debug
-## parsing done in 10 ms
 
-Compress block #1
-(0.002ms) convertToInternal
-(0.000ms) clean
-(0.001ms) compress
-(0.002ms) prepare
-(0.000ms) initialRejoinRuleset
-(0.000ms) rejoinAtrule
-(0.000ms) disjoin
-(0.000ms) buildMaps
-(0.000ms) markShorthands
-(0.000ms) processShorthand
-(0.001ms) restructBlock
-(0.000ms) rejoinRuleset
-(0.000ms) restructRuleset
-## compressing done in 9 ms
+#### minifyBlock(source[, options])
 
-.foo,.test{color:red}
+The same as `minify()` but for style block. Usualy it's a `style` attribute content.
+
+```js
+var result = csso.minifyBlock('color: rgba(255, 0, 0, 1); color: #ff0000').css;
+
+console.log(result.css);
+// > color:red
 ```
 
-More details are provided when `--debug` flag has a number greater than `1`:
+#### parse(source[, options])
 
+Parse CSS to AST.
+
+> NOTE: Currenly parser omit redundant separators, spaces and comments (except exclamation comments, i.e. `/*! comment */`) on AST build, since those things are removing by compressor anyway.
+
+Options:
+
+- context `String` – parsing context, useful when some part of CSS is parsing (see below)
+- positions `Boolean` – should AST contains node position or not, store data in `info` property of nodes (`false` by default)
+- filename `String` – filename of source that adds to info when `positions` is true, uses for source map generation (`<unknown>` by default)
+- line `Number` – initial line number, useful when parse fragment of CSS to compute correct positions
+- column `Number` – initial column number, useful when parse fragment of CSS to compute correct positions
+
+Contexts:
+
+- `stylesheet` (default) – regular stylesheet, should be suitable in most cases
+- `atrule` – at-rule (e.g. `@media screen, print { ... }`)
+- `atruleExpression` – at-rule expression (`screen, print` for example above)
+- `ruleset` – rule (e.g. `.foo, .bar:hover { color: red; border: 1px solid black; }`)
+- `selector` – selector group (`.foo, .bar:hover` for ruleset example)
+- `simpleSelector` – selector (`.foo` or `.bar:hover` for ruleset example)
+- `block` – block content w/o curly braces (`color: red; border: 1px solid black;` for ruleset example)
+- `declaration` – declaration (`color: red` or `border: 1px solid black` for ruleset example)
+- `value` – declaration value (`red` or `1px solid black` for ruleset example)
+
+```js
+// simple parsing with no options
+var ast = csso.parse('.example { color: red }');
+
+// parse with options
+var ast = csso.parse('.foo.bar', {
+    context: 'simpleSelector',
+    positions: true
+});
 ```
-> echo '.test { color: green; color: #ff0000 } .foo { color: red }' | csso --debug 2
-## parsing done in 8 ms
 
-Compress block #1
-(0.000ms) clean
-  .test{color:green;color:#ff0000}.foo{color:red}
+#### compress(ast[, options])
 
-(0.001ms) compress
-  .test{color:green;color:red}.foo{color:red}
+Do the main task – compress AST.
 
-...
+Options:
 
-(0.002ms) restructBlock
-  .test{color:red}.foo{color:red}
+- restructure `Boolean` – do the structure optimisations or not (`true` by default)
+- usage `Object` - usage data for advanced optimisations (see [Usage data](#usage-data) for details)
+- logger `Function` - function to track every step of transformations
 
-(0.001ms) rejoinRuleset
-  .foo,.test{color:red}
+#### translate(ast)
 
-## compressing done in 13 ms
+Converts AST to string.
 
-.foo,.test{color:red}
+```js
+var ast = csso.parse('.test { color: red }');
+console.log(csso.translate(ast));
+// > .test{color:red}
 ```
 
-Using `--debug` option adds stack trace to CSS parse error output. That can help to find out problem in parser.
+#### translateWithSourceMap(ast)
 
+The same as `translate()` but also generates source map (nodes should contain positions in `info` property).
+
+```js
+var ast = csso.parse('.test { color: red }', {
+    filename: 'my.css',
+    positions: true
+});
+console.log(csso.translateWithSourceMap(ast));
+// { css: '.test{color:red}', map: SourceMapGenerator {} }
 ```
-> echo '.a { color }' | csso --debug
 
-Parse error <stdin>: Colon is expected
-    1 |.a { color }
-------------------^
-    2 |
+#### walk(ast, handler)
 
-/usr/local/lib/node_modules/csso/lib/cli.js:243
-                throw e;
-                ^
+Visit all nodes of AST and call handler for each one. `handler` receives three arguments:
 
-Error: Colon is expected
-    at parseError (/usr/local/lib/node_modules/csso/lib/parser/index.js:54:17)
-    at eat (/usr/local/lib/node_modules/csso/lib/parser/index.js:88:5)
-    at getDeclaration (/usr/local/lib/node_modules/csso/lib/parser/index.js:394:5)
-    at getBlock (/usr/local/lib/node_modules/csso/lib/parser/index.js:380:27)
-    ...
+- node – current AST node
+- item – node wrapper when node is a list member; this wrapper contains references to `prev` and `next` nodes in list
+- list – reference to list when node is a list member; it's useful for operations on list like `remove()` or `insert()`
+
+Context for handler an object, that contains references to some parent nodes:
+
+- root – refers to `ast` or root node
+- stylesheet – refers to closest `StyleSheet` node, it may be a top-level or at-rule block stylesheet
+- atruleExpression – refers to `AtruleExpression` node if current node inside at-rule expression
+- ruleset – refers to `Ruleset` node if current node inside a ruleset
+- selector – refers to `Selector` node if current node inside a selector
+- declaration – refers to `Declaration` node if current node inside a declaration
+- function – refers to closest `Function` or `FunctionalPseudo` node if current node inside one of them
+
+```js
+// collect all urls in declarations
+var csso = require('./lib/index.js');
+var urls = [];
+var ast = csso.parse(`
+  @import url(import.css);
+  .foo { background: url('foo.jpg'); }
+  .bar { background-image: url(bar.png); }
+`);
+
+csso.walk(ast, function(node) {
+    if (this.declaration !== null && node.type === 'Url') {
+        var value = node.value;
+
+        if (value.type === 'Raw') {
+            urls.push(value.value);
+        } else {
+            urls.push(value.value.substr(1, value.value.length - 2));
+        }
+    }
+});
+
+console.log(urls);
+// [ 'foo.jpg', 'bar.png' ]
 ```
 
+#### walkRules(ast, handler)
+
+Same as `walk()` but visits `Ruleset` and `Atrule` nodes only.
+
+#### walkRulesRight(ast, handler)
+
+Same as `walkRules()` but visits nodes in reverse order (from last to first).
+
+## More reading
+
+- [Debugging](docs/debugging.md)
+
 ## License
 
 MIT

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