Class: Treetop::Compiler::PredicateBlock

Inherits:
ParsingExpression show all
Defined in:
lib/treetop/compiler/node_classes/predicate_block.rb

Instance Attribute Summary

Attributes inherited from ParsingExpression

#address, #builder, #parent_expression, #subexpression_address, #var_symbols

Attributes inherited from Runtime::SyntaxNode

#input, #interval, #parent

Instance Method Summary collapse

Methods inherited from ParsingExpression

#accumulate_subexpression_result, #accumulator_var, #assign_failure, #assign_lazily_instantiated_node, #assign_result, #begin_comment, #declared_module_name, #decorated?, #end_comment, #epsilon_node, #extend_result, #extend_result_with_declared_module, #extend_result_with_inline_module, #init_value, #inline_module_name, #node_class_name, #obtain_new_subexpression_address, #on_one_line, #optional_arg, #reset_index, #result_var, #start_index_var, #subexpression_result_var, #subexpression_success?, #use_vars, #var, #var_initialization

Methods inherited from Runtime::SyntaxNode

#<=>, #dot_id, #elements, #empty?, #extension_modules, #initialize, #inspect, #inspect_children, #inspect_self, #nonterminal?, #terminal?, #text_value, #write_dot, #write_dot_file

Constructor Details

This class inherits a constructor from Treetop::Runtime::SyntaxNode

Instance Method Details

#compile(index, builder, parent_expression = nil) ⇒ Object 



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# File 'lib/treetop/compiler/node_classes/predicate_block.rb', line 4

def compile(index, builder, parent_expression = nil)
  super
  # REVISIT: This is distinctly dodgey, but since we can only be called from
  # two contexts, and it works in both those, I'm going with it for now, as
  # opposed to doing the major refactor of providing a proper way of accessing
  # the parent's accumulator variable.
  p = parent
  p = p.parent while p && !p.respond_to?(:accumulator_var)
  assign_result "lambda #{text_value}.call(#{p ? p.accumulator_var : ""})"
  builder.if_ '!'+result_var do
    builder << "terminal_parse_failure(#{expected})"
  end
end

#expected ⇒ Object 



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# File 'lib/treetop/compiler/node_classes/predicate_block.rb', line 18

def expected
  '"<semantic predicate>"'  # Should I include (some of) the text_value here?
end