NetNews Usenet Archive 1992 #27/NN_1992_27.iso/spool/comp/lang/perl/7044

Text File | 1992-11-18 | 2.0 KB | 46 lines

Newsgroups: comp.lang.perl
Path: sparky!uunet!charon.amdahl.com!pacbell.com!sgiblab!sgigate!sgi!wdl1!wdl39!mab
From: [e-mail] (Mark A Biggar)
Subject: Re: cpp fails in statements like pkg'foo(DEFINE)
Message-ID: <[e-mail]>
Sender: [e-mail]
Organization: Loral Western Development Labs
References: <[e-mail]>
Date: Wed, 18 Nov 1992 18:02:09 GMT
Lines: 34

In article <[e-mail]> [e-mail] (Christoph Adomeit) writes:
>what is the golden way to prevent cpp from interpreting
>a statement like
>#define DEFINE 99
>pkg'foo(DEFINE)
>as a part of a string literal ?
>In the above examples DEFINE is not replaced by "99" because
>cpp thinks it's a string literal.
>--
>Origin: It's not a bug, it's a feature !

Unfortunately, a lot of CPPs out there insist on tokenizing their input as if
it was a C source file.  What did you expect, it's a C preprocessor and the
C standard specifically allows CPP to do this.  Of course, this means that
some CPPs cannot be used to preprocess Perl scripts, but it's only a
historical accident that the CPP on the machine Larry originally developed
Perl on had a CPP that could be used to preprocess Perl scripts.  That feature
was originally added to Perl very early to get the include file processing of
PCC, the #define stuff was only incidential.  Now that 'do' and 'require' have
been added to the language, the main reason for using CPP has gone away, and
it could be argued that CPP support should be dropped from the Perl interpreter
or a macro processor specifically designed for Perl should be created.  Note:
all these problems with CPP are some of the reasons why the ch2p tool converts
#define CPP lines into perl subroutines.

In answer to your question, No there is no way to tell your CPP to do things
the way you want.  Either find a different (probably older) CPP that works
your way or don't use CPP.

--
Perl's Maternal Uncle
Mark Biggar
[e-mail]