Re: reset function (never)

[Anonymous Monk]

never use the reset function to reset variables

Also read Tutorials: Variable Scoping in Perl: the basics,
Coping with Scoping , Mini-Tutorial: Perl's Memory Management,
Lexical scoping like a fox,

Also

Learn Perl in about 2 hours 30 minutes
chromatics free book Modern Perl a loose description of how experienced and effective Perl 5 programmers work....You can learn this too.
PLEAC - Programming Language Examples Alike Cookbook

[LanX]

Once in a while I repeat saying something like

"Perl doesn't stop to surprise me!"

And I always hope the intervals between these moments will get bigger...

But now... oh man ... this reset builtin is really scary!

  DB<132> @x=(4,2);$x=42; $y=0; 
          while ($y++<3) {
             $x=$y; 
             print "$x -" ; 
             reset('x') if $y>1 ;
             print " $x : @x\n"; 
          }
1 - 1 : 4 2
2 -  : 
3 -  :

IMHO it doesn't "reset" at all, it just deletes all variables of the glob *x without deleting the glob.

Only delete $main::{'x'} is more radical...

o_O WTF !?!

update

Me thinks this must be a relict of one-liner hacking. Anything else is just to dangerous..

[boftx]

WOW!! WTF, indeed! I can understand something that would reset a match, but variables that start with a given letter? Can someone provide a use-case for this that makes sense?

[Anonymous Monk]

Can someone provide a use-case for this that makes sense?

I thought surely the use case is perl4, but it wasn't available in perl4, it became available in perl5, and looks to be http://perldoc.perl.org/perlapi.html#sv_reset exposed

It is barely used (one place) http://perl5.git.perl.org/perl.git?a=search&h=HEAD&st=grep&s=sv_reset

I guess, larry thought, it may be useful for Perl ... but it turned out to not be useful for Perl, and its kind of deprecated :)

Maybe the thinking was where  local $foo_one, $foo_bar,...; can get tedious,  reset 'f'; saves typing,

anyway, reset simply appeared from larry with perl5a2 20 years ago

For comparison of old cruft in perl see Re^2: Perl format line breaking, $FORMAT_LINE_BREAK_CHARACTERS apparently ignored