Class: BabelBridge::Rule

Inherits:
Object
  • Object
show all
Defined in:
lib/babel_bridge/rule.rb

Overview

Rules define one or more patterns (RuleVariants) to match for a given non-terminal

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, parser) ⇒ Rule

Returns a new instance of Rule.



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# File 'lib/babel_bridge/rule.rb', line 20

def initialize(name,parser)
  @name = name
  @variants = []
  @parser = parser
  @node_class = create_node_class
end

Instance Attribute Details

#name ⇒ Object

Returns the value of attribute name.



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# File 'lib/babel_bridge/rule.rb', line 4

def name
  @name
end

#node_class ⇒ Object

Returns the value of attribute node_class.



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# File 'lib/babel_bridge/rule.rb', line 4

def node_class
  @node_class
end

#parser ⇒ Object

Returns the value of attribute parser.



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# File 'lib/babel_bridge/rule.rb', line 4

def parser
  @parser
end

#variants ⇒ Object

Returns the value of attribute variants.



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# File 'lib/babel_bridge/rule.rb', line 4

def variants
  @variants
end

Instance Method Details

#add_variant(options = {}, &block) ⇒ Object 



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# File 'lib/babel_bridge/rule.rb', line 31

def add_variant(options={}, &block)
  new_variant_node_class.tap do |variant_node_class|
    options[:variant_node_class] = variant_node_class
    options[:rule] = self
    variants << RuleVariant.new(options)
    variant_node_class.class_eval &block if block
  end
end

#inspect ⇒ Object

inspect returns a string which approximates the syntax for generating the rule and all its variants



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# File 'lib/babel_bridge/rule.rb', line 56

def inspect
  variants.collect do |v|
    "rule #{name.inspect}, #{v.inspect}"
  end.join("\n")
end

#parse(node) ⇒ Object 



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# File 'lib/babel_bridge/rule.rb', line 40

def parse(node)
  if cached = node.parser.cached(name,node.next)
    return cached == :no_match ? nil : cached # return nil if cached==:no_matched
  end

  variants.each do |v|
    if match = v.parse(node)
      node.parser.cache_match(name,match)
      return match
    end
  end
  node.parser.cache_no_match(name,node.next)
  nil
end

#root_rule? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/babel_bridge/rule.rb', line 27

def root_rule?
  parser.root_rule == name
end

#to_s ⇒ Object

returns a more human-readable explanation of the rule



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# File 'lib/babel_bridge/rule.rb', line 63

def to_s
  "rule #{name.inspect}, node_class: #{node_class}\n\t"+
  "#{variants.collect {|v|v.to_s}.join("\n\t")}"
end