Class: Pegarus::Choice

Inherits:
BinaryOp show all
Defined in:
lib/pegarus/ast/choice.rb,
lib/pegarus/rubinius/compiler.rb

Instance Attribute Summary

Attributes inherited from BinaryOp

#first, #second

Instance Method Summary collapse

Methods inherited from BinaryOp

#initialize

Methods inherited from Pattern

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

Constructor Details

This class inherits a constructor from Pegarus::BinaryOp

Instance Method Details

#bytecode(g) ⇒ Object 



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# File 'lib/pegarus/rubinius/compiler.rb', line 151

def bytecode(g)
  g.push_index # store index, so that we can restart
  old_fail = g.fail
  done = g.new_label

  choice_fail = g.new_label
  g.fail = choice_fail
  @first.bytecode(g)
  g.pop # success, pop index
  g.fail = old_fail # reset fail
  g.goto done

  choice_fail.set!
  g.fail = old_fail
  g.set_index # reset index to the stored index, this pops the value
  @second.bytecode(g)

  done.set!
end

#visit(visitor) ⇒ Object 



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# File 'lib/pegarus/ast/choice.rb', line 3

def visit(visitor)
  visitor.choice self
end