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From: bin@primate.wisc.edu (Brain in Neutral)
Newsgroups: comp.windows.x
Subject: Re: R5 and Imake
Message-ID: <2910@uakari.primate.wisc.edu>
Date: 10 Aug 90 18:09:23 GMT
References: <1767@idunno.Princeton.EDU>
Sender: bin@primate.wisc.edu
Reply-To: bin@primate.wisc.edu
Lines: 33

From article <1767@idunno.Princeton.EDU>, by rhl@grendel.Princeton.EDU (Robert Lupton (the Good)):
> 
> The more I learn about Imake the more times I come across admissions
> that things are made extra-specially-convoluted to avoid unhappy habits
> of cpp. 
> ... 
> I'd volunteer, except that I'm not that familiar with imake... Maybe
> another fun project for poor Paul DuBois?

Well, one of the things cpp is used for in X is to create scripts from
template files.  It seems that the use of cpp in those instances is mainly
to substitute into the template the values of certain make variables, e.g.,
like a library directory into a shell script.

As you've noted, there are certain problems with this.  As I would put it,
the main ones are:

(1) cpp modifies its source besides symbol substitution, e.g., lines
beginning with ``#'' are special and comments (``/* ... */'') are deleted.
(2) it is necessary to pass a -D flag for every symbol to be substituted.
This can make for very long rule invocations in your Imakefile.  Hard to
read and subject to error.  And it's simply a pain to have to explicitly
list every symbol you want to substitute.

Why not read the Makefile directly, yank out the variable values, look
for instances of $(varname) or ${varname) in the template, and substitute
the values - and leave everything else alone?

That's why I wrote msub.
Mail me if you're interested.

Paul DuBois
dubois@primate.wisc.edu