Re: Bring back the smartmatch operator (but with sane semantics this time)!

A lot of the discussion so far has hinged on how to tell strings from numbers (eq vs. ==), so I'm surprised no-one has mentioned Scalar::Util's looks_like_number() yet... the only downsides I see so far are that it might not be as fast as some other heuristic, and that sometimes I might want to actually compare two numbers as strings explicitly. (Okay one more... looks_like_number recognizes a few strings as numbers, such as "Inf", "Infinity", "NaN" and "0 but true". And it doesn't recognize "1_000" as a number... hmmm. See Perl_grok_number() in numeric.c)

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Re^2: Bring back the smartmatch operator (but with sane semantics this time)! by tobyink (Canon) on Jun 11, 2014 at 20:56 UTC
The string/number heuristic is responsible for some of the oddest behaviour of smart match. Let's take for example the use of `$x ~~ @array` as an "in" operator. `sub as_bool { $_[0] ? "true" : "false" } my @greetings = qw( Hi Bye ); say as_bool("Hi" ~~ @greetings); # true say as_bool("Hiya" ~~ @greetings); # false` [download] OK, everything is working as expected so far. Now let's do something a little more complex... `push @greetings, 0, 1; say as_bool(0 ~~ @greetings); # true say as_bool(1 ~~ @greetings); # true say as_bool(2 ~~ @greetings); # false say as_bool("Hiya" ~~ @greetings); # true ?!?!` [download] `use Moops; class Cow :rw { has name => (default => 'Ermintrude') }; say Cow->new->name`	[reply] [d/l] [select]
Re^3: Bring back the smartmatch operator (but with sane semantics this time)! by Anonymous Monk on Jun 12, 2014 at 22:14 UTC
Not having memorized the smartmatch table, that looked pretty strange to me at first, but looking at the table, at least it's well-defined... and when I tried it I got a "`Argument "Hiya" isn't numeric in smart match`" warning, which (although it's not much) is better than it silently matching. But the problem of when to match with `==` vs. `eq` remains...	[reply] [d/l] [select]