Re^3: Why split function treats single quotes literals as regex, instead of a special case?

The regular expression // works differently in split then elsewhere:

$ perl -le'
my $x = "1234 abcd 5678";
print $& if $x =~ /[a-z]+/;
print $& if $x =~ //;
print map qq[ "$_"], split /[a-z]+/, $x;
print map qq[ "$_"], split //, $x;
'
abcd
abcd
 "1234 " " 5678"
 "1" "2" "3" "4" " " "a" "b" "c" "d" " " "5" "6" "7" "8"
[download]

Also, the line anchors /^/ and /$/ don't require the /m option to match lines in a string.

Comment on Re^3: Why split function treats single quotes literals as regex, instead of a special case? Download Code

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Re^4: Why split function treats single quotes literals as regex, instead of a special case? by AnomalousMonk (Archbishop) on Aug 14, 2020 at 18:17 UTC
The regular expression // works differently in split then elsewhere... I think I'd consider this just another special-case fixup prior to running split rather than a true difference in the function of `m//`: `c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le "my $x = qq{1234 abcd 5678}; dd split //, $x; dd split /\b\|\B/, $x; " (1 .. 4, " ", "a" .. "d", " ", 5 .. 8) (1 .. 4, " ", "a" .. "d", " ", 5 .. 8)` [download] This is probably just a matter of emphasis and interpretation. ... line anchors /^/ and /$/ don't require the /m option to match lines in a string. Checking the docs, I recalled seeing this discussed before, but it's another one of those very specialized special cases that evaporates from my memory with time. However, it's not true for the `/$/` case (per the docs (or at any rate, the docs say nothing about special-casing it)): `c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le "my $x = qq{1234 \n abcd \n 5678}; dd split /^/, $x; dd split /$/, $x; " ("1234 \n", " abcd \n", " 5678") "1234 \n abcd \n 5678"` [download] Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]
Re^4: Why split function treats single quotes literals as regex, instead of a special case? by jcb (Parson) on Aug 14, 2020 at 23:07 UTC
The regular expression // works differently in split then elsewhere I think it is actually the other way around — in most contexts, `m//` is special (it refers to the most recent pattern without duplicating that pattern), while in `split`, `//` is literally the empty regex, which matches the zero-length empty string.	[reply] [d/l] [select]