From: Bob Hutchison <hutch@...>
Date: 2005-09-11T22:58:11+09:00
Subject: Re: r4 - the simplest ruby pre-processor

Hi,

With a tiny change to this you can also use ruby's embedded value  
substitution (interpolation), like:

     |
     | some_number = 42
     |

     Hello there!

     some number: [[[#{some_number}]]]

to get output like:

     Hello there!

     some number: [[[42]]]

That one change is from:


>         "puts #{line.chomp.dump}\n"
>

to:

     "puts \"#{line.chomp}\"\n"

(just added the quotes).

This is a very interesting little toy. Maybe not a toy at all.

Cheers,
Bob

On Sep 11, 2005, at 7:38 AM, Christian Neukirchen wrote:


> "Ara.T.Howard" <Ara.T.Howard@noaa.gov> writes:
>
>
>
>> all this talk about pre-processors and erb got me thinking : what  
>> would it
>> take to code up a ruby pre-procssors that could be used for any  
>> laguange.  my
>> first crack is 38 lines of ruby that pre-process any files on the  
>> command line
>> (or stdin) using ruby as the macro language and a convenience  
>> function 'macro'
>> which can be used to define ruby methods which return test that is  
>> used as
>> output.  functions declared this way need not do any explicit io.
>>
>>
>
> Alternative implementation ("r5"):
>
>     def macro(name, &block)
>       Kernel.send(:define_method, name) { |*args|
>         puts block.call(args)
>       }
>     end
>
>     send(($DEBUG ? "puts" : "eval"), ARGF.readlines.map { |line|
>       if line[0] == ?|
>         line[1..-1]
>       else
>         "puts #{line.chomp.dump}\n"
>       end
>     }.join)
>
> Happy hacking,
> -- 
> Christian Neukirchen  <chneukirchen@gmail.com>  http:// 
> chneukirchen.org
>
>
>

----
Bob Hutchison          -- blogs at <http://www.recursive.ca/hutch/>
Recursive Design Inc.  -- <http://www.recursive.ca/>
Raconteur              -- <http://www.raconteur.info/>