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parser.js
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parser.js
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// Core modules
var fs = require('fs')
var path = require('path')
var Stream = require('stream').Stream
var vm = require('vm')
var isArray = require('util').isArray
// Modules
var debug = require('debug')('atok-parser')
var EV = require('ev')
var inherits = require('inherits')
var _eval = require('eval')
var Atok = require('atok')
var fnutils = require('fnutils')
// Local files
var Helpers = require('./helpers')
var Tracker = require('./tracker')
debug("atok version %s", Atok.version)
// Copy properties from one object to another - not replacing if required
function merge (a, b, soft) {
for (var k in b)
if (!soft || !a.hasOwnProperty(k)) a[k] = b[k]
return a
}
// Show special characters for display
function inspect (s) {
return s
.replace(/\\/g, '\\\\')
.replace(/\n/g, '\\n')
.replace(/\t/g, '\\t')
.replace(/"/g, '\\"')
.replace(/\r/g, '\\r')
}
merge(Atok.prototype, Helpers)
exports.Helpers = Helpers
// Expose the Atok module for addition of custom helpers
exports.Atok = Atok
// Export version
exports.version = require('../package.json').version
/**
* createParser(data, parserOptions, parserEvents, atokOptions)
* - data (String | Array): parser javascript code
* - parserOptions (String): list of the parser named events with their arguments count
* - parserEvents (Object): events emitted by the parser with
* - atokOptions (Object): tokenizer options
*
* Return a parser class (Function) based on the input file.
* The following variables are made available to the parser js:
* - atok (Object): atok tokenizer instanciated with provided options. Also
* set as this.atok *DO NOT DELETE*
* - self (Object): reference to this
* Predefined methods:
* - write
* - end
* - pause
* - resume
* - track
* Events automatically forwarded from tokenizer to parser:
* - drain
* - debug
*/
exports.createParser = function (data, parserOptions, parserEvents, atokOptions, filename) {
filename = filename || ''
// Merge the supplied events with Atok's (overwrite)
var _parserEvents = merge(parserEvents || {}, Atok.events)
// Set an event arguments list
function forwardEvent (event) {
var n = Atok.events[event]
, args = []
while (n > 0) args.push('a' + n--)
args = args.join()
return 'atok.on("'
+ event
+ '", function forwardEvent (' + args + ') { self.emit_' + event + '(' + args + ') })'
}
// Set the parser options
parserOptions = parserOptions || (typeof data === 'function' ? fnutils.head(data) : '')
// Set the constructor name
var cname = typeof data === 'function' && data.name ? data.name : 'Parser'
// Define the parser constructor
var content = []
content.push(
'function ' + cname + ' (' + parserOptions + ') {'
, 'if (!(this instanceof ' + cname + ')) {'
, 'return new ' + cname + '(' + parserOptions + ') }'
, 'EV.call(this, ' + JSON.stringify(_parserEvents) + ')'
, 'this.readable = true'
, 'this.writable = true'
, 'this.debugMode = false'
, 'var self = this'
, 'var atok = new Atok(' + (atokOptions ? JSON.stringify(atokOptions): '') + ')'
, forwardEvent('drain')
, forwardEvent('debug')
, 'this.atok = atok'
, 'var atokTracker = new Tracker(atok)'
, 'this.atokTracker = atokTracker'
, 'function error (err, data) {'
, 'atok.pause()'
, 'return self.trackError(err, data)'
, '}'
, isArray(data)
? data.join(';')
: typeof data === 'function'
? fnutils.body(data)
: data
, '}'
, 'inherits(' + cname + ', EV, Stream.prototype)'
, 'module.exports = ' + cname
, ''
)
var Parser = _eval(
content.join(';')
, filename
, {
__filename: filename
, __dirname: path.dirname(filename)
// Custom exposed globals
, Atok: Atok
, Tracker: Tracker
, EV: EV
, Stream: Stream
, inherits: inherits
}
)
// Apply the parser stream methods to the tokenizer
Parser.prototype.pause = function () {
this.atok.pause()
return this
}
Parser.prototype.resume = function () {
this.atok.resume()
return this
}
Parser.prototype.write = function (data) {
return this.atok.write(data)
}
Parser.prototype.end = function (data) {
this.atok.end(data)
return this
}
Parser.prototype.destroy = function () {}
// Proxy some tokenizer methods
Parser.prototype.setEncoding = function () {
this.atok.setEncoding( arguments[0] )
return this
}
// Debug
Parser.prototype.debug = function (flag) {
var _debug = !!flag
// Nothing to do if already in same mode
if (_debug === this.debugMode) return this
this.atok.debug(_debug)
if (typeof flag === 'function') this.on('debug', flag)
return this
}
// Track current line and column
// type: {Boolean}
Parser.prototype.track = function (flag) {
this.atokTracker[ flag === true ? 'start' : 'stop' ]()
return this
}
// Build error message based on the current position in the buffer
Parser.prototype.trackError = function (err, data, delta) {
err = err || new Error
data = data || ''
delta = typeof delta === 'number' ? delta : 10
var atok = this.atok
var size = data.length
var pos = atok.offset
var tracker = this.atokTracker
var msg = 'rule: ' + atok.currentRule()
if (tracker.running) {
var margin = 4
var line = tracker.y
var column = tracker.x + 1
// Extract some data from the current position: some left, some right
var left = Math.max(0, pos - delta)
var leftExtract = atok.slice(left, pos)
var leftInspected = inspect(leftExtract)
var right = Math.min(atok.length, pos + delta)
var rightExtract = atok.slice(pos, right)
var rightInspected = inspect(rightExtract)
// Position of the cursor below the displayed data
var cursor = pos - left + margin + leftInspected.length - leftExtract.length
msg += ', line: '
msg += line
msg += ', column: '
msg += column
msg += '\n'
// Data sample around the current buffer position
msg += Array(margin + 1).join(' ')
msg += leftInspected
msg += rightInspected
msg += '\n'
// Offset the cursor
msg += Array(cursor).join(' ')
// Add the cursor
msg += Array((Math.min(size, right - pos) || 1) + 1).join('^')
} else {
msg += ', token: '
msg += inspect( data )
}
msg += '\n'
err.message += err.message.length ? ', ' + msg : msg
return merge(err, {
line: line
, column: column
, token: data
, rule: atok.currentRule()
})
}
return Parser
}
/**
* createParserFromFile(file, parserOptions, parserEvents, atokOptions)
* - file (String): file to read the parser from(.js extension is optional but enforced)
* - parserOptions (String): list of the parser named events with their arguments count
* - parserEvents (Object): events emitted by the parser with
* - atokOptions (Object): tokenizer options
*/
exports.createParserFromFile = function (file, parserOptions, parserEvents, atokOptions) {
// Append .js extension if not set
var filename = file.slice(-3) === '.js' ? file : file + '.js'
// Figure out the file full path
filename = path.resolve( path.dirname(module.parent.filename), filename )
return exports
.createParser(
fs.readFileSync(filename).toString()
, parserOptions
, parserEvents
, atokOptions
, filename
)
}