@solidity-parser/parser

What is @solidity-parser/parser?

@solidity-parser/parser is an npm package designed to parse Solidity source code into an Abstract Syntax Tree (AST). This allows developers to analyze, transform, and manipulate Solidity code programmatically. It is particularly useful for building tools that need to understand the structure of Solidity code, such as linters, code formatters, and static analysis tools.

What are @solidity-parser/parser's main functionalities?

Parsing Solidity Code

This feature allows you to parse Solidity source code into an Abstract Syntax Tree (AST). The code sample demonstrates how to parse a simple Solidity contract and print the resulting AST.

const parser = require('@solidity-parser/parser');
const sourceCode = 'contract MyContract { uint256 public value; }';
const ast = parser.parse(sourceCode);
console.log(JSON.stringify(ast, null, 2));

Handling Parse Errors

This feature allows you to handle errors that occur during parsing. The code sample demonstrates how to catch and handle a parse error when the Solidity source code is incomplete or malformed.

const parser = require('@solidity-parser/parser');
const sourceCode = 'contract MyContract { uint256 public value;'; // Missing closing brace
try {
  const ast = parser.parse(sourceCode);
} catch (error) {
  console.error('Parse error:', error);
}

Traversing the AST

This feature allows you to traverse the AST and perform actions on specific nodes. The code sample demonstrates how to traverse the AST and print the name of each contract defined in the Solidity source code.

const parser = require('@solidity-parser/parser');
const sourceCode = 'contract MyContract { uint256 public value; }';
const ast = parser.parse(sourceCode);
parser.visit(ast, {
  ContractDefinition: (node) => {
    console.log('Contract name:', node.name);
  }
});

Other packages similar to @solidity-parser/parser

solidity-ast

solidity-ast is a package that provides utilities for working with the AST produced by the Solidity compiler. It is more tightly integrated with the Solidity compiler itself and is useful for tasks that require detailed information from the compiler's output. Compared to @solidity-parser/parser, it is more focused on post-compilation analysis.

solparse

solparse is another Solidity parser that converts Solidity code into an AST. It is similar to @solidity-parser/parser but is less actively maintained. It provides basic parsing capabilities but may lack some of the more advanced features and error handling provided by @solidity-parser/parser.

README

Solidity Parser for JavaScript

A JavaScript package for parsing Solidity code using ANTLR (ANother Tool for Language Recognition) grammar.

This is a fork of @federicobond's original repo, with some extra features taken from Consensys Diligence's alternative fork.

Installation

The following installation options assume Node.js has already been installed.

Using Node Package Manager (npm).

npm install @solidity-parser/parser

Using yarn

yarn add @solidity-parser/parser

Usage

const parser = require('@solidity-parser/parser')

const input = `
    contract test {
        uint256 a;
        function f() {}
    }
`
try {
  const ast = parser.parse(input)
  console.log(ast)
} catch (e) {
  if (e instanceof parser.ParserError) {
    console.error(e.errors)
  }
}

The parse method also accepts a second argument which lets you specify the following options, in a style similar to the esprima API:

Key	Type	Default	Description
tolerant	Boolean	false	When set to true it will collect syntax errors and place them in a list under the key errors inside the root node of the returned AST. Otherwise, it will raise a parser.ParserError.
loc	Boolean	false	When set to true, it will add location information to each node, with start and stop keys that contain the corresponding line and column numbers. Column numbers start from 0, lines start from 1.
range	Boolean	false	When set to true, it will add range information to each node, which consists of a two-element array with start and stop character indexes in the input.

Example with location information

parser.parse('contract test { uint a; }', { loc: true })

// { type: 'SourceUnit',
//   children:
//    [ { type: 'ContractDefinition',
//        name: 'test',
//        baseContracts: [],
//        subNodes: [Array],
//        kind: 'contract',
//        loc: [Object] } ],
//   loc: { start: { line: 1, column: 0 }, end: { line: 1, column: 24 } } }

Example using a visitor to walk over the AST

var ast = parser.parse('contract test { uint a; }')

// output the path of each import found
parser.visit(ast, {
  ImportDirective: function (node) {
    console.log(node.path)
  },
})

Usage in the browser

A browser-friendly version is available in dist/index.umd.js (along with its sourcemaps file) in the published version.

If you are using webpack, keep in mind that minimizing your bundle will mangle function names, breaking the parser. To fix this you can just set optimization.minimize to false.

Contribution

This project is dependant on the @solidity-parser/antlr repository via a git submodule. To clone this repository and the submodule, run

git clone --recursive

If you have already cloned this repo, you can load the submodule with

git submodule update --init

This project can be linked to a forked @solidity-parser/antlr project by editing the url in the .gitmodules file to point to the forked repo and running

git submodule sync

The Solidity ANTLR file Solidity.g4 can be built with the following. This will also download the ANTLR Java Archive (jar) file to antlr/antlr4.jar if it doesn't already exist. The generated ANTLR tokens and JavaScript files are copied the src folder.

yarn run antlr

The files to be distributed with the npm package are in the dist folder and built by running

yarn run build

The mocha tests under the test folder can be run with the following. This includes parsing the test.sol Solidity file.

yarn run test

Used by

• Hardhat
• sol2uml
• Solhint
• solidity-coverage
• prettier-solidity
• eth-gas-reporter

License

MIT