Class: Rattler::Parsers::Assert

Inherits:

Predicate

• Object
• Util::Node
• Parser
• Predicate
• Rattler::Parsers::Assert

Defined in:

lib/rattler/parsers/assert.rb

Overview

Assert decorates a parser and succeeds or fails like the decorated parser but never consumes any input.

Author:

• Jason Arhart

Instance Method Summary

• #parse(scanner, rules, scope = {}) ⇒ Boolean

  Succeed or fail like the decorated parser but do not consume any input and return true on success.

Methods inherited from Predicate

#capturing?, parsed, #with_ws

Methods inherited from Parser

#&, #capturing?, #labeled?, #one_or_more, #optional, parsed, #skip, #variable_capture_count?, #with_ws, #zero_or_more, #|

Methods inherited from Util::Node

#==, [], #[], #attrs, #can_equal?, #child, #children, #each, #empty?, #eql?, #initialize, #inspect, #method_missing, #name, #respond_to?, #same_contents?, #to_graphviz, #with_attrs, #with_attrs!, #with_children

Constructor Details

This class inherits a constructor from Rattler::Util::Node

Dynamic Method Handling

This class handles dynamic methods through the method_missing method in the class Rattler::Util::Node

Instance Method Details

#parse(scanner, rules, scope = {}) ⇒ Boolean

Succeed or fail like the decorated parser but do not consume any input and return true on success.

Returns:

• (Boolean) —

  true if the decorated parser succeeds

# File 'lib/rattler/parsers/assert.rb', line 25

def parse(scanner, rules, scope = {})
  pos = scanner.pos
  result = (child.parse(scanner, rules, scope) && true)
  scanner.pos = pos
  result
end