[PPL-devel] [Fwd: Re: Finding spurious spacing in m4 texts]

[Roberto Bagnara]

-------- Original Message --------
Subject: Re: Finding spurious spacing in m4 texts
Date: Fri, 19 Sep 2008 07:51:57 -0600
From: Jack Woehr <jax at well.com>
To: Roberto Bagnara <bagnara at cs.unipr.it>
References: <48D35540.5090402 at cs.unipr.it>

Roberto Bagnara wrote:
>  we have
> a system composed by several m4 texts and quite often
> we end up with spurious spacing in the output.
>
I have had that problem, and sometimes spent a very long time debugging!

Over the years, the best help for me has been following coding patterns,
such as

     * never over-quote
     * always exactly one or no spaces in arguments after a comma before
       a backtick (`)
     * always no spaces after the closing tick (') of an argument
     * no dnl on lines where they are not needed (e.g. when the stream is
       diverted to null)

etc. etc.

If you do everything all the same, then it either works all the time or
fails all the time!

For debugging, I suppose the easiest "trick" is to insert and obtrusive
meaningless text
such as `FOOBAR' here and there in the source and find its orientation
in relation to the spurious spacing.

-- 
Jack J. Woehr            # "Self-delusion is
http://www.well.com/~jax #  half the battle!"
http://www.softwoehr.com #  - Zippy the Pinhead



-- 
Prof. Roberto Bagnara
Computer Science Group
Department of Mathematics, University of Parma, Italy
http://www.cs.unipr.it/~bagnara/
mailto:bagnara at cs.unipr.it