From: Young Tae Kim <philos99@...>
Date: 2009-03-10T08:36:46+09:00
Subject: Re: Treetop Parser whitespace

Clifford Heath wrote:
> Young tae Kim wrote:
>> I can't understand why the following test fails.
>> Could you tell me why? Thanks, in advance.
> 
> It works for me. What version of Treetop and Polyglot
> are you using. Can you please tell us what is printed
> by "puts parser.failure_reason"?
> 
> Clifford Heath.

I revised my example like this but it doesn't work as well.

# in arithmetic.treetop

grammar Arithmetic
  rule num
    [1-9] [0-9]* {
      def value
        text_value
      end
    }
  end

  rule space
    [ \t\n\r]+ {
      def value
        text_value
      end
    }
  end
end



# in test_parser.rb

require "rubygems"
require "treetop"
require "arithmetic"

parser = ArithmeticParser.new

p parser.parse("123")
p parser.parse("   \n\t\r")
puts parser.failure_reason



# the execution result

$ ruby test_parser.rb
SyntaxNode+Num1+Num0 offset=0, "123" (value):
  SyntaxNode offset=0, "1"
  SyntaxNode offset=1, "23":
    SyntaxNode offset=1, "2"
    SyntaxNode offset=2, "3"
nil
nil

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