Class: Parse::RockitProductionsEvaluator

Inherits:
Object
  • Object
show all
Defined in:
lib/rpdf2txt-rockit/rockit_grammar_ast_eval.rb

Instance Method Summary collapse

Constructor Details

#initialize(tokens = []) ⇒ RockitProductionsEvaluator

Returns a new instance of RockitProductionsEvaluator.



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# File 'lib/rpdf2txt-rockit/rockit_grammar_ast_eval.rb', line 120

def initialize(tokens = [])
  @token_map = Hash.new
  tokens.each {|token| @token_map[token.name] = token}
end

Instance Method Details

#eval_ast(ast) ⇒ Object 



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# File 'lib/rpdf2txt-rockit/rockit_grammar_ast_eval.rb', line 125

def eval_ast(ast)
  return nil unless ast
  case ast.name
  when "Productions"
  ast.productions.map {|prod| eval_ast(prod)}.flatten
  when "Prod"
  nonterminal = eval_ast(ast.nonterminal)
  ast.alts.map do |alt| 
    elements, treespec = eval_ast(alt)
    prod(nonterminal, elements, treespec)
  end
  when "Alt"
  [ast.elements.map {|e| eval_ast(e)}, 
    eval_ast(ast.astspec)]
  when "SymbolName"
  symbol = ast.lexeme
  @token_map[symbol] || symbol.intern
  when "ImplicitToken"
  eval(ast.regexp.lexeme) # Eval to String or Regexp
  when "Maybe"
  maybe(eval_ast(ast.element))
  when "Plus"
  plus(eval_ast(ast.element))
  when "Mult"
  mult(eval_ast(ast.element))
  when "Or"
  ore(*(ast.elements.map {|e| eval_ast(e)}))
  when "Sequence"
  ast.elements.map {|e| eval_ast(e)}
  when "List"
  liste(eval_ast(ast.element), eval_ast(ast.delimiter))
  when "AstSpec"
  if ast.elemspecs
    elemspecs = ast.elemspecs.map {|e| e.lexeme.intern}
  else
    elemspecs = []
  end
  if ast.prodspec
    prodspec = (ast.prodspec.lexeme == "^" ? :^ :eval_ast(ast.prodspec))
  else
    prodspec = nil
  end
  stb(prodspec, elemspecs)
  when "Lift"
  :^
  end
end