Class: Treetop::Compiler::Choice

Inherits:
ParsingExpression show all
Defined in:
lib/treetop/compiler/node_classes/choice.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(address, builder, parent_expression = nil) ⇒ Object 



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

def compile(address, builder, parent_expression = nil)
  super
  begin_comment(self)
  use_vars :result, :start_index
  compile_alternatives(alternatives, parent_expression)
  end_comment(self)
end

#compile_alternatives(alternatives, parent_expression) ⇒ Object 



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# File 'lib/treetop/compiler/node_classes/choice.rb', line 12

def compile_alternatives(alternatives, parent_expression)
  obtain_new_subexpression_address
  alternatives.first.compile(subexpression_address, builder)
  builder.if__ subexpression_success? do
    # Undo lazy instantiation:
    builder << "#{subexpression_result_var} = SyntaxNode.new(input, (index-1)...index) if #{subexpression_result_var} == true"
    assign_result subexpression_result_var
    extend_result_with_declared_module
    extend_result_with_inline_module parent_expression
  end
  builder.else_ do
    if alternatives.size == 1
      reset_index
      assign_failure start_index_var
    else
      compile_alternatives(alternatives[1..-1], parent_expression)
    end
  end
end

#expected ⇒ Object 



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# File 'lib/treetop/compiler/node_classes/choice.rb', line 32

def expected
  '"(any alternative)"'
end