Dr.Ruud wrote:
> "Chas Owens" schreef:
>> Dr.Ruud:
>
>>> Some evaluation is done first:
>>>
>>> perl -Mstrict -MData::Dumper -wle'
>>> $_ = {0b1_0 => "A", 01_0 => "B", 0x1_0 => "C", 1_0 => "D", _1_0 =>
>>> "E", *_ => "F", \_ => "G"};
>>> print Dumper $_
>>> '
>>> $VAR1 = {
>>> '8' => 'B',
>>> '_1_0' => 'E',
>>> '*main::_' => 'F',
>>> '10' => 'D',
>>> '16' => 'C',
>>> 'SCALAR(0x8062850)' => 'G',
>>> '2' => 'A'
>>> };
>> snip
>>
>> Nope, it has nothing to do with evaluation.
>
> Ah, you misunderstood my "evaluation" which had nothing to do with
> eval(). Maye I should have used "parsing and compiling".
>
>
>> The trick is that it only
>> works on barewords (matches /[_A-Za-z][_A-Za-z0-9]*/). 0b1_0 is not a
>> bareword because it starts with a number. The same goes for 01_0,
>> 0x1_0, and 1_0. _1_0 works because barewords may start with an
>> underscore. *_ and \_ are definitely not a barewords since they
>> contain characters that are not even in the allowed set. Anything
>> that fails the bareword test is treated as if the '=>' operator were a
>> normal ',' operator.
>
> Yes, "passing the bareword test" is a better phrase than only mentioning
> "word" characters.
>
> There are border cases though:
>
> perl -Mstrict -MData::Dumper -wle'
> $_ = { AB => 1, +AB => 2, -AB => 3 };
> print Dumper $_
> '
> $VAR1 = {
> '-AB' => 3,
> 'AB' => 2
> };
It depends on what you mean by "border case"?
$ perl -Mstrict -MData::Dumper -wle'
$_ = { 67 => 1, +67 => 2, -67 => 3 };
print Dumper $_
'
$VAR1 = {
'67' => 2,
'-67' => 3
};
Unary plus and unary minus appear to be behaving correctly. :-)
John
--
Perl isn't a toolbox, but a small machine shop where you can special-order
certain sorts of tools at low cost and in short order. -- Larry Wall
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