Re^2: Easy Reference for Contexts

For instance I doubted that scalar m// returns true or false (those identifiers don't exist in Perl), I thought it's the number of matches returned.
But I was wrong: :)
DB<23> $_="aaa" DB<24> print scalar m/a/ 1
[download]

Anything in Perl is true or false. Or rather, ANYTHING is true but undef is false. 😋

Like the relops, m//, s///, and y/// can all return the magical false value, that secret special value that nobody talks about:

% perl -wle 'printf "got %d matches\n", scalar ANYTHING =~ /nothing/'
got 0 matches

So I shan’t, either. 😜

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Re^3: Easy Reference for Contexts by LanX (Saint) on Apr 15, 2011 at 10:11 UTC
> Or rather, ANYTHING is true but undef is false. Many things in Perl are evaluated to false in boolean context, not only `undef`. Cheers Rolf	[reply] [d/l]
Re^4: Easy Reference for Contexts by JavaFan (Canon) on Apr 15, 2011 at 10:48 UTC
Tom is right. ANYTHING is true: `$ perl -E 'say +ANYTHING ? "true" : "false"' true` [download]	[reply] [d/l]
Re^5: Easy Reference for Contexts by LanX (Saint) on Apr 15, 2011 at 11:14 UTC
Ladys and gentleman, let me introduce the new "author context"! If you senseą a hidden guru identity behind a novice account, reread a post with amplified irony-factor ... ;-) Cheers Rolf 1) just be careful if you see magical unicode "switches" in the text ... --------------------------- UPDATEs: `DB<119> sub ANYTHING {} DB<120> print "false" unless ANYTHING false` [download] not feasible with `undef`. -------- Funnily in Python it's easily possible to globally redefine `False` and `True`... `> python Python 2.5.2 (r252:60911, Jan 20 2010, 23:16:55) [GCC 4.3.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> False,True=True,False >>> False True >>> True False` [download]	[reply] [d/l] [select]