Auto-increment and Auto-decrement

[kiseok7]

[John M. Dlugosz]

The perlop man page states,

The auto-increment operator has a little extra builtin magic to it. If you increment a variable that is numeric, or that has ever been used in a numeric context, you get a normal increment. If, however, the variable has been used in only string contexts since it was set, and has a value that is not the empty string and matches the pattern...

It doesn't say the decrement works the same way. Too bad; one would think so without reading the docs carefully.

—John

update: see Magical Auto-Decrement.

[kiseok7]

very thanks!

[Albannach]

This is one of those little bits of "magic" that you find scattered all over Perl. It's simply that only autoincrement has the magical effect on text, autodecrement does not, so it sees your text as a numeric 0 (zero) and hence you get -1.

--
I'd like to be able to assign to an luser

[Anonymous Monk]

Well, do you mean "why" in the Zen sense? I don't know. But, quoth the manual,

Auto-decrement is not magical.

May be a good question to post on P6P....

HTH

[tilly]

It doesn't work because nobody can agree how autodecrement should work on strings.

For a sample of what I mean, read the p5p starting at this innocent-seeming question.