Asp Forum - YAML for Ruby: How to turn off the boolean interpretations?

mikshir

12/9/2005 8:57:00 PM

I have YAML documents generated in Perl and Python that I process with
Ruby.

Problem: Ruby wants to auto-interpret boolean flagged words, example:

---
words:
- yes
- put
- it
- on
- the
- off
- setting

gets loaded in Ruby as

[true, "put", "it", true, "the", false, "setting"]

Basically the latest Perl and Python YAML modules I could find won't
quote some of the words that Ruby's YAML would. (Things like on, off,
yes, no, +) Perhaps they conform to a different version of the YAML
spec. I find the incompatibility a bit frustrating. I can and have
easily hacked the other modules to do the compatible thing but there
are political admin maintenance issues surrounding my patching all the
company computers with this.

I'll not comment right now on whether I think it was a good idea to
flag these items as special to begin with. I'd just like to know if
there's a simple module over-ride hack or module parameter setting that
I can set or clip into my scripts to deal with this problem.

Thanks.

5 Answers

daz

12/10/2005 6:52:00 AM

mikshir wrote:
>
> Problem: Ruby wants to auto-interpret boolean flagged words, [...]
>

Hi Mikshir,

Hadn't heard about those :-? Interesting.

>
> I'll not comment right now on whether I think it was a good idea to
> flag these items as special to begin with. I'd just like to know if
> there's a simple module over-ride hack or module parameter setting that
> I can set or clip into my scripts to deal with this problem.
>
> Thanks.
>

This isn't anything official, so caution is recommended.

Successive changes to YAML.rb mean that I've had to stitch
two fixes. The relevant one should auto-select and it
seems to work for the following Rubys:

1.8.0 (2003-08-30)
1.8.2 (2004-12-25)
1.8.3 (2005-07-22)
1.8.4 (2005-12-01)
1.9.0 (2005-10-31)

It re-categorises all bool types as normal strings and
doesn't touch any other types.

Note that, as well as inserting the module addition in your
scripts, you must use:
YAML.parse(foo).transform
^^^^^^^^^^^^^^^^^^^^^^^^^
in place of YAML.load
http://yaml4r.sourceforge.net/doc/class/yaml_parser_parse_...

<fix/test below> - email me if any problem(s).

daz
--

require 'yaml'

#----------------------------------------------------------------------
module YAML::Syck
BOOL_RE = /bool#\w+\z/
if defined?(Loader)
class Loader
alias_method :o_transfer, :transfer
def transfer(type_id, val)
(String === type_id) and type_id.gsub!(BOOL_RE, 'str')
o_transfer(type_id, val)
end
end
else
class Node
alias_method :o_transform, :transform
def transform
kind == :scalar and self.type_id = type_id.gsub(BOOL_RE, 'str')
o_transform
end
end
end
end
#----------------------------------------------------------------------

hobj = YAML.parse(<<EoS).transform
---
words:
- yes
- put
- it
- on
- the
- off
- setting
EoS

if hobj['words'] == %w{ yes put it on the off setting }
puts ' ***---> S U C C E S S <---***'
else
p hobj
end

Logan Capaldo

12/10/2005 6:58:00 AM

On Dec 9, 2005, at 3:57 PM, mikshir wrote:

> I have YAML documents generated in Perl and Python that I process with
> Ruby.
>
> Problem: Ruby wants to auto-interpret boolean flagged words, example:
>
> ---
> words:
> - yes
> - put
> - it
> - on
> - the
> - off
> - setting
>
> gets loaded in Ruby as
>
> [true, "put", "it", true, "the", false, "setting"]
>
> Basically the latest Perl and Python YAML modules I could find won't
> quote some of the words that Ruby's YAML would. (Things like on, off,
> yes, no, +) Perhaps they conform to a different version of the YAML
> spec. I find the incompatibility a bit frustrating. I can and have
> easily hacked the other modules to do the compatible thing but there
> are political admin maintenance issues surrounding my patching all the
> company computers with this.
>
> I'll not comment right now on whether I think it was a good idea to
> flag these items as special to begin with. I'd just like to know if
> there's a simple module over-ride hack or module parameter setting
> that
> I can set or clip into my scripts to deal with this problem.
>
> Thanks.
>
>

Well, I was looking at the YAML site, and apparently yes/no on/off
are part of a draft specification, it looks like ruby is just ahead
of the curve, so to speak.

http://yaml.org/type...

This of course, fails to help you.

The only solution I could come up with, in a word, sucks.

require 'yaml'

test = YAML.parse(FIle.read("test.yml")) # where test.yml contains
that ---\n words: -yes -no etc.
test.children[0].value.each do |x|
if x.type_id =~ /bool#(?:yes|no)\z/
x.type_id = "tag:yaml.org,2002:str"
end
end

results = test.transform #=> {"words"=>["yes", "put", "it", "on",
"the", "off", "setting"]}

Of course this iteration will only work for that file, since I made
some massive assumptions about the structure. Your other option is to
do a search and replace on the yess, ons,offs, etc and quote them
before parsing.

daz

12/10/2005 7:00:00 AM

I wrote:
>
> http://yaml4r.sourceforge.net/doc/class/yaml_parser_parse_...
>

Huh? It changed in transit :/ Should be:
http://yaml4r.sourceforge.net/doc/class/yaml_parse_...

Ara.T.Howard

12/10/2005 7:17:00 AM

Logan Capaldo

12/10/2005 7:27:00 AM

On Dec 10, 2005, at 2:16 AM, ara.t.howard@noaa.gov wrote:
>
> why not simply conform to the spec? :
>
>

I believe that the documents are being generated by Python and/or
Perl and he is (for whatever reason) not allowed to mess with that part.

comp.lang.ruby

YAML for Ruby: How to turn off the boolean interpretations?

mikshir

daz

Logan Capaldo

daz

Ara.T.Howard

Logan Capaldo

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