Treetop Parser whitespace

Ruby
1

I can’t understand why the following test fails.
Could you tell me why? Thanks, in advance.

in arithmetic.treetop

grammar Arithmetic
rule white_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(" \n\t\r")

the execution result

$ ruby test_parser.rb
nil

2

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 H…

3

Clifford H. 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 H…

First of all, many thanks for your reply!

The version of the operating system is Ubuntu 8.10

the ruby version is ruby 1.8.7 (2008-08-11 patchlevel 72) [x86_64-linux]

The following is the result of gem list --local

$ gem list --local

*** LOCAL GEMS ***

actionmailer (2.2.2)
actionpack (2.2.2)
activerecord (2.2.2)
activeresource (2.2.2)
activesupport (2.2.2)
cgi_multipart_eof_fix (2.5.0)
daemons (1.0.10)
fastthread (1.0.1)
gem_plugin (0.2.3)
hoe (1.9.0)
mongrel (1.1.5)
polyglot (0.2.5) <----
rails (2.2.2)
rake (0.8.3)
rubyforge (1.0.3)
sqlite3-ruby (1.2.4)
treetop (1.2.4) <----

What’s printed by “puts parser.failure_reason” is just “nil”.

4

Clifford H. 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 H…

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

5

I got an answer. If you face the same problem, please refer to the
following site.

http://groups.google.com/group/treetop-dev/browse_thread/thread/417aaf6fdac25fe3

6

Young Tae Kim wrote:

What’s printed by “puts parser.failure_reason” is just “nil”.

I think that’s a bug. I don’t have time to investigate it right now.
BTW, if you run the command “tt arithmetic.tt”, you’ll get the
generated “arithmetic.rb” code that you can explore.

Clifford H.