On 18.12.2011 23:18, Mike Samuel wrote:
2011/12/17 Dmitry Soshnikov<dmitry.soshni...@gmail.com>:
Hi,
Just recently was working with Ruby's code. And found useful again its
(actually from Perl) "approximately equal" operator: =~
Perl's =~ operator is more comparable to String.prototype.match than
RegExp.prototype.test.
Perl operators can be used in either scalar or list contexts unlike
ecmascript (see perldoc for wantarray) and it's true that =~ produces
a boolean when used in a scalar context, but since match returns null
on zero matches, it can still be used in conditions. When used in a
non-scalar context, =~ produces a list of the matches:
perl -e 'my $s = "foo"; print join ",", ($s =~ /o/g)'
prints
o,o
Perhaps, I don't know Perl enough. The talk isn't about Perl though. We
may adjust the semantics for ES as _we_ wish, not Perl.
Even ignoring order of evaluation, desugaring a ~= b to b.test(a)
would cause the seemingly straightforward
var myRegex = /foo/g; // Used for a global replace in other code.
if ("foo" ~= myRegex) { alert(1); }
if ("foo" ~= myRegex) { alert(2); }
if ("foo" ~= myRegex) { alert(3); }
to alert 1 and 3 only.
Because of lastIndex, I understand. Though nobody says we have to
directly desugar it to .test(...) method. Obviously, it should handle
the case correctly.
Dmitry.
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