[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: config.status - robust sed substitutions
From: |
Robert Anderson |
Subject: |
Re: config.status - robust sed substitutions |
Date: |
26 Feb 2003 16:34:41 -0800 |
On Wed, 2003-02-26 at 15:43, Paul Eggert wrote:
> > I don't think this (^^^) is of sufficient complexity to make it worth
> > living with the uncertainties of choosing another character and hoping
> > it doesn't cause problems.
>
> It's not a question of complexity; it's a question of reliability and
> portability.
Ok, we agree on that.
> Here-documents are dangerous; we've learned this from
> experience.
There are 24 different here-documents in status.m4 to generate
config.status, so it seems like no compromise unless I'm doing something
which specifically triggers bugs or limitations in some here-document
implementations. Perusing the autoconf docs, I'll take a closer look at
size limitations.
> If you don't like '|', how about tab? It's reasonable to prohibit
> tabs in file names.
I'd agree, but remember that the RHS of these substitutions is not only
filenames. There's also other text, as in $configure_input, for
example.
The choice of tab is an interesting one; I'd be more worried about the
portability of that than a here-document (possibly unfounded, I dunno).
Not to mention the "huh?" factor in source readability.
However, note that _any_ new choice of delimiter will not only fail for
the case of the chosen character, but will also fail for the characters
'@' and '\' which are always metacharacters on the RHS of a sed
expression. I've seen '@' in particular in pathnames out in the wild;
it's a good prefix to get files to sort to the top of an 'ls'.
With a preprocessing step, you can solve all three problems
simultaneously (arbitrary delimiter, '@', and '\').
Bob
- config.status - robust sed substitutions, Robert Anderson, 2003/02/26
- Re: config.status - robust sed substitutions, Paul Eggert, 2003/02/26
- Re: config.status - robust sed substitutions, Robert Anderson, 2003/02/26
- Re: config.status - robust sed substitutions, Paul Eggert, 2003/02/26
- Re: config.status - robust sed substitutions,
Robert Anderson <=
- Re: config.status - robust sed substitutions, Robert Anderson, 2003/02/26
- Re: config.status - robust sed substitutions, Paul Eggert, 2003/02/27
- Re: config.status - robust sed substitutions, Robert Anderson, 2003/02/27
- Re: config.status - robust sed substitutions, Andreas Buening, 2003/02/28
- Re: config.status - robust sed substitutions, Robert Anderson, 2003/02/26