From: Francis Cianfrocca <garbagecat10@...>
Date: 2006-05-13T11:44:24+09:00
Subject: Re: lightweigth lexer?

------=_Part_38535_19439200.1147488260522
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: quoted-printable
Content-Disposition: inline

If you look closely at what traditional tools like lex and flex do, you
could almost take the input to lex and execute it directly in Ruby! It's no=
t
much more than a case statement from regular expressions. I'm not sure what
you mean by "lightweight" but if you mean "fast": a lot of people who wrote
language compilers back in the day (I'm one of them) would often write
scanners in hand-tuned C rather than using lex.

On 5/12/06, Meador Inge <meadori@gmail.com> wrote:
>
> Is there lightweight lexer for Ruby? I have seen a few lexer
> generators out there, but I want something simple that can be used
> without generating the lexer first. I really just need the basic
> functionaliy of matching a pattern and associating an action with that
> pattern. For example, I was thinking something like:
>     class MyLexer < Lexer
>        rule /a/ do
>           # action for pattern a
>        end
>        rule /b/ do
>           # action for pattern b
>        end
>        rule /c/ do
>           # action for pattern c
>        end
>     end
>
>     l =3D MyLexer.new(input_stream)
>     l.each_token do |token|
>        # do something with token
>     end
>
> I have something similar to the above that I have created. However, I
> wanted to check and see what is out there first before I invested too
> much time in it. If no one knows of anything else and\or is interested
> in what I have described let me know and I will clean it up and
> publish it.
>
> --Meador
>
>

------=_Part_38535_19439200.1147488260522--