zerkel

#zerkel An adzerk-based query-ish language.

###Language Zerkel provides primitive integer and string literals, identifiers, sets, and a selection of boolean operators:

operator/type	comment	examples
integers	syntax	42, -7
strings	syntax	"foo", "C:\\\\Windows\\System32", `"^(foo
variables	syntax	count, _foo_bar, $location.postalCode
.	property accessor	$location.postalCode, foo.bar.baz
[, ]	set construction	[42, "foo"]
(, )	expression grouping	x < 100 AND (y < 50 OR z < 10)
=		foo = 42
<>	not equal	foo <> "bar"
=~	regex match	`foo =~ "^(some
!~	not regex match	`foo !~ "^(some
>		foo > 42
<		foo < 42
>=		foo >= 42
<=		foo <= 42
AND		foo = 42 AND bar < 100
OR		foo = 42 OR bar < 100
NOT		NOT (bar =~ "^foo")
LIKE	wildcard match	foo LIKE "ba*"
CONTAINS	set membership / substring	["foo", "bar"] CONTAINS "foo", "foobar" CONTAINS "foo"

Thus, queries may be written like:

count > 43 and (user = "bob" or user = "alice")
keywords contains "awesome"

All operators are available in upper and lowercase forms.

###Demo

Check out the live Zerkel scratchpad demo app and try some zerkel queries in your browser.

###Usage Queries can executed in coffeescript/javascript using the zerkel module, like so:

zerkel = require 'zerkel'

query = 'count > 43 and (user = "bob" or user = "alice")'
matchFn = zerkel.compile query
matchFn {count: 50, user: 'bob'} # true
matchFn {count: 12, user: 'alice'} # false
matchFn {count: 50, user: 'George Michael'} # terribly, unfortunately, false

You can also access properties on passed in objects, like so:

zerkel = require 'zerkel'

query = 'user.location = "open field west of a white house"'
matchFn = zerkel.compile query
matchFn {user: {name: 'bob', location: 'open field west of a white house'}} # true
matchFn {user: {name: 'alice', location: 'middle earth'}} # false

###Gzip Set the parser.MIN_GZIP_SIZE to a number, and if the length of the compiled JavaScript is greater than that it will be gzipped and base64 encoded, with GZ: prepended. The zerkel#makePredicate function will unzip automatically as necessary.

parser = require 'zerkel-parser'

parser.MIN_GZIP_SIZE = 50
parser.parse 'foo = 42'              # _helpers['getIn'](_env, 'foo')==42'
parser.parse '[42, 43] contains foo' # GZ:H4sIAAAAAAAAA9OINjHSMTGOVVODMvQy81JSK/zTNOIzUnMKUouKo9XTU0s889RjNeJT88p0FNTT8vPVNTUV7GwVDDQBm8CsuD8AAAA=

###Status

###License Apache 2.0