Coding styles that make me twitch, part 6

Edit: There are, apparently, strong feelings that I should not post my personal preferences. Reader discretion advised: this post expresses my personal opinions regarding a limited use case for file handling and filehandles, and must not be read as general advise on how to deal with filehandles in Perl, and so on.

Today's theme is: unnecessary variable clutter.

my $fh = new Filehandle("/usr/bin/somecmd someargs |");
while (my $l=<$fh>) {
    if ($l=~m/foo bar zot/) {
        # lots of code that does not depend on
        # a variable file handle, nor creative
        # usage of $l where $_ could not be used
        # implicitly just as easily
    }
}

Sure, there are situations where it makes sense to assign filehandles to variables, or using $l instead of $_, but the above example is not one of them. I found no particular reason why the original programmer had used new Filehandle, either.

Perl 5 has, on purpose, made this easier for us than in the above example:

open my $FH, '-|', '/usr/bin/somecmd someargs'
    or croak "OMG\n";
while (<$FH>) {
    if (/foo bar zot/) {
        # lots of code
    }
}

Missing feature

A few hours ago, I suddenly had a bright(?) idea, or desire if you will:

Proper (Unicode) exponents in Perl.

That is, I want to be able to write 2², 4¹³⁷, 3^-9, etc. and have Perl understand them.

For Perl 5, I suspect someone would use a source filter to implement it.

For Perl 6, PerlJam++ suggested introducing each of the exponents as postfix operators, using this example for squaring:

our &postfix:<2> := &infix:<**>.assuming(b => 2);

But then a negative exponent would complicate things a bit.

It's a thought, anyway, and not one that I'd want to distract more pressing implementation concerns.

And ifwhen someone decides that this is a good idea to have in the language core, I'll start nagging about Knuth's up-arrow notation. Not that I'd want anyone attempt calculating 4↑↑↑↑4.

Spooky

This is just a small anecdote.

Tonight, I finished a small Perl 5 script that I've been wanting to complete for a while, but where I was a bit nervous that I'd fsck it up right and good.

It was a script designed to handle two tab-separated text sources; one a list of tournament IDs and tournament names, the other a list of player results, one line per result with the player ID, tournament name, position and score achieved.

I achieved this by creating a hash of hashes for each file, referencing the first while parsing the other, and bravely inserting the data into a single database table.

I tested my code piece for piece while building it, which is sensible in itself, but what spooked me was this:

There was not a single bug. The script did what it was supposed to do, all along.

That's not supposed to happen.

I need a drink.