perl, was Re: [plug] Merging 2 files, CVS-style

[Peter Wright]

On Thu, Apr 13, 2000 at 03:36:55PM +0800, Mike Holland wrote:
> A pity you dont have the common ancestor.
> Whats wrong with Perl BTW?

Nothing, just that where it's not strictly needed (as in a case like
this, where 98% of the "real work" is done by external programs) and
bourne shell is up to the glue work, it's _probably_ preferable to do
it in shell.

Just that I hardly ever do bourne shell programming cos I always have
Perl :).

> Its perfect for that kind of thing - no need to run 'grep' or 'cut'
> externally.
> It can be a lot 'neater' too, .e.g.
> 	 sub gtr {return $_[0] > $_[1] ? $_[0] : $_[1]; }

Yes, I was thinking as I typed that function out that it could
probably be done in a much more compact fashion, but I'd finished
typing the function before my brain had finished processing that
thought.

(and no, that means I'm a fast typist, not (just) a slow thinker :)

> and system("diff -u$size $f1 $f2 | grep '^ ' | cut -c2- > $merge");
> becomes something like:
> 
> 	$merge = map '/^ (.*)$/' `diff -u$size $f1 $f2`;

Or rather:

	@merge_lines = map '/^ (.*)$/' `diff -u$size $f1 $f2`;
	$merge = join('', @merge_lines);

Otherwise, according to perlfunc(1):
	"In scalar context, returns the total number of elements so
	generated."

Although I haven't tested it so that still might not be "right". :)

> I like perl. Such a great hack.

There's More Than One Way To Do It.

Or, more appropriately in this case, Whatever Gets The Job Done Before
Your Boss Fires You.

> Mike Holland  <mike at golden.wattle.id.au>

:)

Pete.
-- 
http://cygnus.uwa.edu.au/~pete/

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