Class: Pegarus::Grammar

Inherits:
Pattern show all
Defined in:
lib/pegarus/ast/grammar.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from Pattern

#*, #+, #+@, #-, #-@, #/, engine, #graph, #match, select_engine, #visit

Constructor Details

#initialize(variable = nil) ⇒ Grammar

Returns a new instance of Grammar.



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# File 'lib/pegarus/ast/grammar.rb', line 21

def initialize(variable=nil)
  if variable
    @start = variable.name
    set_variable variable.name, variable.pattern
  end
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(sym, *args) ⇒ Object 



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# File 'lib/pegarus/ast/grammar.rb', line 46

def method_missing(sym, *args)
  name = sym.to_s

  if name[-1] == ?= and args.size == 1
    set_variable name[0..-2], args.first
  else
    get_variable name
  end
end

Instance Attribute Details

#start ⇒ Object

Returns the value of attribute start.



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# File 'lib/pegarus/ast/grammar.rb', line 19

def start
  @start
end

Instance Method Details

#get_variable(name) ⇒ Object 



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# File 'lib/pegarus/ast/grammar.rb', line 34

def get_variable(name)
  if metaclass.method_defined? name
    variable = send name
  else
    vname = name.to_sym
    variable = Variable.new vname
    metaclass.thunk_method vname, variable
  end

  variable
end

#set_variable(name, pattern) ⇒ Object 



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# File 'lib/pegarus/ast/grammar.rb', line 28

def set_variable(name, pattern)
  variable = get_variable name
  variable.pattern = pattern
  variable
end