Re^5: Why is "any" slow in this case?

[ikegami]

Why do we need $1 to be magic, when it's read-only?

We don't need it to be. As I mentioned, the alternative would be to make make a copy of the matched text on match. The down side is that this would happen even if $1 isn't used. Same goes for all the other vars I mentioned.

if this is about avoiding overhead for optional variables, retrieving it just once on demand would be sufficient.

That's not how magic works. Get magic changes a variable from something that stores a value, to a function that produces the value on demand. You can either store the value in the var, or generate it each time the var is accessed.

[LanX]

OK I always took the word "magic" as term for various "implementation quirks" in Perl and not as a well defined mechanism.

Variable::Magic suggests otherwise ...

... learning every day something new. :)

[ikegami]

Correct, I'm referring to the magic added by sv_magic.

$ perl -MDevel::Peek -e'Dump( $1 )'
SV = PVMG(0x561e81adde40) at 0x561e81af86f0
  REFCNT = 1
  FLAGS = (GMG,SMG)                # Has get magic, has set magic
  IV = 0
  NV = 0
  PV = 0
  MAGIC = 0x561e81b067d0           # Magic's data, incl callbacks
    MG_VIRTUAL = &PL_vtbl_sv
    MG_TYPE = PERL_MAGIC_sv(\0)
    MG_OBJ = 0x561e81af86d8
    MG_LEN = 1

Magic is used by most punctuation vars (e.g. $!, $$, %ENV, %SIG), tie, lvalue operators (specifically substr, vec, pos and $#a), f( $h{ x } ) (to prevent autovivification) and more.