Module: Piggly::Parser

Defined in:
lib/piggly/parser.rb,
lib/piggly/parser/nodes.rb,
lib/piggly/parser/traversal.rb

Overview

Pl/pgSQL Parser, returns a tree of NodeClass values (see nodes.rb)

Defined Under Namespace

Modules: Nodes, Traversal Classes: Failure

Class Method Summary collapse

Class Method Details

.grammar_path ⇒ Object 



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# File 'lib/piggly/parser.rb', line 32

def grammar_path; "#{File.dirname(__FILE__)}/parser/grammar.tt" end

.nodes_path ⇒ Object 



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# File 'lib/piggly/parser.rb', line 33

def nodes_path;   "#{File.dirname(__FILE__)}/parser/nodes.rb"   end

.parse(string) ⇒ Object

Returns lazy parse tree (only parsed when the value is needed)



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# File 'lib/piggly/parser.rb', line 15

def parse(string)
  Util::Thunk.new do
    p = parser

    begin
      # Downcase input for case-insensitive parsing
      input = string.downcase
      tree = p.parse(input)
      tree or raise Failure, "#{p.failure_reason}"
    ensure
      # Restore the original string after parsing
      input.replace(string)
    end
  end
end

.parser ⇒ Object

Returns treetop parser (recompiled as needed)



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# File 'lib/piggly/parser.rb', line 36

def parser
  load_support

  # @todo: Compare with the version of treetop
  if Util::File.stale?(parser_path, grammar_path)
    # Regenerate the parser when the grammar is updated
    Treetop::Compiler::GrammarCompiler.new.compile(grammar_path, parser_path)
    load parser_path
  else
    require parser_path
  end

  ::PigglyParser.new
end

.parser_path ⇒ Object 



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# File 'lib/piggly/parser.rb', line 31

def parser_path;  "#{File.dirname(__FILE__)}/parser/parser.rb"  end