nkohari / zerkel

An adzerk-based query-ish language.

#zerkel An adzerk-based query-ish language.

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

Types:

• integer — 42
• string — "foo"
• identifier — count
• set — [42, "foo"]

Operations:

• = — foo = 42
• <> (not equal) — foo <> "bar"

• — foo > 42

• < — foo < 42

• = — foo >= 42

• <= — foo <= 42
• LIKE — foo LIKE "ba*"
• CONTAINS — [42, 43] 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.

###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