Created
February 27, 2014 16:55
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var SequenceRule = function() { | |
var parts = arguments; | |
if(!parts.length) return function(phase, onmatch, onfail) { | |
return onmatch(phase, '') | |
} | |
var last = parts[parts.length - 1]; | |
var trailing = function(phase, onmatch, onfail){ | |
last(phase, function(phase1, result){ onmatch(phase1, [result]) }, onfail) | |
}; | |
for(var j = parts.length - 2; j >= 0; j--) { | |
trailing = (function(trailing, part){ | |
return function(phase, onmatch, onfail){ | |
return part(phase, function(phase1, result){ | |
return trailing(phase1, function(phase2, result2){ | |
return onmatch(phase2, [result].concat(result2)) | |
}, onfail) | |
}, function(reason){ | |
return onfail(reason) | |
}) | |
} | |
})(trailing, parts[j]); | |
} | |
return trailing; | |
} | |
var AlternateRule = function() { | |
var alternates = arguments; | |
if(!alternates.length) return function(phase, onmatch, onfail) { | |
return onfail(phase, '') | |
} | |
var last = alternates[alternates.length - 1]; | |
var trailing = function(phase, onmatch, onfail){ | |
last(phase, onmatch, onfail) | |
}; | |
for(var j = alternates.length - 2; j >= 0; j--) { | |
trailing = (function(trailing, alternate){ | |
return function(phase, onmatch, onfail){ | |
return alternate(phase, function(phase1, result){ | |
return onmatch(phase1, result) | |
}, function(reason){ | |
return trailing(phase, onmatch, onfail) | |
}) | |
} | |
})(trailing, alternates[j]); | |
} | |
return trailing; | |
} | |
var LiteralRule = function(lit){ | |
return function(phase, onmatch, onfail){ | |
if(phase.source.slice(phase.offset, phase.offset + lit.length) === lit){ | |
return onmatch({source: phase.source, offset: phase.offset + lit.length}, lit) | |
} else { | |
return onfail("Expecting " + lit) | |
} | |
} | |
} | |
var ActionRule = function(rule, action){ | |
return function(phase, onmatch, onfail){ | |
rule(phase, function(phase1, result){ | |
return onmatch(phase1, action(result)) | |
}, onfail) | |
} | |
} | |
var Noun = AlternateRule(LiteralRule('car'), LiteralRule('plane')) | |
var Verb = AlternateRule(LiteralRule('runs'), LiteralRule('flys')) | |
var Adverb = AlternateRule(LiteralRule('fast'), LiteralRule('high')) | |
var Space = LiteralRule(' ') | |
var Spaces = function(p, m, f){ | |
return Spaces(p, m, f); | |
}; | |
Spaces = ActionRule(AlternateRule(SequenceRule(Space, Spaces), Space), function(){ return null }); | |
var Setence = SequenceRule(Noun, Spaces, Verb, Spaces, Adverb) | |
Setence({source: 'car runs fast', offset: 0}, function(phase, result){ console.log(result) }, function(reason){ console.log(reason) }) |
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