Re^3: Why is "any" slow in this case?

My point was this:

use v5.40;
my @subs;
sub dosomething :prototype(&) { push @subs, $_[0]; }
for (1..2) {
  my $x;
  dosomething { $x+1 }
}
for (1..2) {
  my $x;
  dosomething { $_+1 }
}
say for @subs
[download]

Output:

CODE(0x56271152c660)
CODE(0x5627115470c8)
CODE(0x5627115999e0)
CODE(0x5627115999e0)
[download]

You can see by the addresses that Perl had to allocate a new coderef on each iteration of the first loop, but was able to reuse the coderef on the second loop.

Comment on Re^3: Why is "any" slow in this case? Select or Download Code

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Re^4: Why is "any" slow in this case? by ikegami (Patriarch) on Aug 05, 2025 at 01:52 UTC
In a dump, the closure has the CLONED flag. You can also see the capture. SV = IV(0x582c494d89d0) at 0x582c494d89e0 REFCNT = 1 FLAGS = (ROK) RV = 0x582c494b36b0 SV = PVCV(0x582c495314a8) at 0x582c494b36b0 REFCNT = 2 FLAGS = (ANON,CLONED,CVGV_RC,DYNFILE) COMP_STASH = 0x582c494b3530 "main" START = 0x582c494f9298 ===> 1 ROOT = 0x582c494f9220 GVGV::GV = 0x582c494eed80 "main" :: "__ANON__" FILE = "-" DEPTH = 0 FLAGS = 0x14c0 OUTSIDE_SEQ = 218 PADLIST = 0x582c494ca480 PADNAME = 0x582c494f87a0(0x582c494d5cc0) PAD = 0x582c494d8878(0x58 +2c494df290) 1. 0x582c494eeb88<2> FAKE "$x" flags=0x0 index=2 OUTSIDE = 0x0 (null) [download]	[reply] [d/l]
Re^4: Why is "any" slow in this case? by LanX (Saint) on Aug 04, 2025 at 21:28 UTC
Yeah I see your point now. Seems like Perl is playing safe if a lexpad is required for the closure, even if the closed over lexical variable doesn't change, like here: `$ perl use v5.14; my @subs; sub dosomething :prototype(&) { push @subs, $_[0]; } my $x; for (1..2) { dosomething { $x+1 } } for (1..2) { my $x; dosomething { $_+1 } } say for @subs; __END__ CODE(0x64405f0de700) CODE(0x64405f10b340) CODE(0x64405f118bb0) CODE(0x64405f118bb0)` [download] BTW: Clever move to push the code-refs to @subs and keeping them alive instead of printing them out. Like this you are avoiding that Perl tries to reuse a freed ref again! IOW if we see the same ref again we are sure teh sub wasn't generated again. Cheers Rolf _{(addicted to the Perl Programming Language :) see Wikisyntax for the Monastery}	[reply] [d/l]