[Dub-pm] 'Shortening' code.

Fergal Daly fergal at esatclear.ie
Sat Apr 24 06:42:43 CDT 2004

On Sat, Apr 24, 2004 at 09:56:20AM +0100, Dave O Connor wrote:
> I guess I should have mentioned readability, too. While it can't immediately
> be said that a one-liner is slower (in fact, it's probbaly faster, unless
> you've used a module just to squash it down from several lines), it can
> usually be said that it's less readable. For example, the author of the
> module gives the following example for slurping a file:
> open my $file_handle, './Scotty' or die "Scotty can't be slurped:\n$!";
> local $/;   # Set input to "slurp" mode.
> my $big_string = <$file_handle>;
> close $file_handle;
> An equivalent (and more readable way is:
> open(FH,"Scotty") or die "Scotty can't be slurped:\n$!";
> my $big_string = join('',<FH>);
> close(FH);

The author gave the first as an example of boilerplate code that's all over
everyone's Perl scripts. Your version is slightly shorter but could be a
whack load slower due to having to parse the file into lines and then join
them all up again. Plus it stomps on the FH package variable which may or
may not be OK.

my $big_string = io('./Scotty')->slurp;

is far more readable than either of those and would probably be faster than
the 3-liner and a tiny bit slower than the 4-liner.

Perl is full of boilerplate code and any module that gets rid of it without
imposing severe penalties is ok by me,

> While this is more 'idiomatic', it's still obvious to someone with a good
> grounding in perl what is going on here, and it's definitely not worth writing
> a module for to 'simplify' your code down the the almighty one-liner :)

This is a 1-liner but it's a 1-liner due to abstraction, not due to
compaction. A 1-liner (well slightly more) by compaction would be

my $big_string =
do{local($/,*F);open(F, "./Scotty')||die"Scotty can't be slurped\n$!";<F>}

and that definitely is a bad idea,


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