Class: Citrus::ButPredicate

Inherits:
Object show all
Includes:
Nonterminal
Defined in:
lib/citrus.rb

Overview

A ButPredicate is a Nonterminal that consumes all characters until its rule matches. It must match at least one character in order to succeed. The Citrus notation is any expression preceded by a tilde, e.g.:

~expr

Constant Summary collapse

DOT_RULE = 
Rule.for(DOT)

Instance Attribute Summary

Attributes included from Nonterminal

#rules

Attributes included from Rule

#extension, #grammar, #label, #name

Instance Method Summary collapse

Methods included from Nonterminal

#grammar=

Methods included from Rule

#==, #===, #default_options, #elide?, #extend_match, for, #inspect, #needs_paren?, #parse, #terminal?, #test, #to_embedded_s, #to_s

Constructor Details

#initialize(rule = '') ⇒ ButPredicate

Returns a new instance of ButPredicate.



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# File 'lib/citrus.rb', line 1073

def initialize(rule='')
  super([rule])
end

Instance Method Details

#exec(input, events = []) ⇒ Object

Returns an array of events for this rule on the given input.



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# File 'lib/citrus.rb', line 1083

def exec(input, events=[])
  length = 0

  until input.test(rule)
    len = input.exec(DOT_RULE)[-1]
    break unless len
    length += len
  end

  if length > 0
    events << self
    events << CLOSE
    events << length
  end

  events
end

#rule ⇒ Object

Returns the Rule object this rule uses to match.



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# File 'lib/citrus.rb', line 1078

def rule
  rules[0]
end

#to_citrus ⇒ Object

Returns the Citrus notation of this rule as a string.



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# File 'lib/citrus.rb', line 1102

def to_citrus # :nodoc:
  '~' + rule.to_embedded_s
end