Re: Re: quoting style for lists

I see, what use should any unary '-' with bareword have apart from being a shell-option-like string? Thanks.
But even the use of -barewords at other positions than before => and inside $hash{keys} is hairy anyway:

use strict; use warnings;

sub foo(){ 'x' }

$_ = -foo; # Ambiguous use of -foo 
           # resolved as -&foo() at ./ol line 8.

print; # '-x'

sub bar() { -1 }
$_ = -bar; #Ambigous ... as -&bar() ...
print; # 1 !not "--1"

my %h = ( -foo => 'FOO' );
print keys %h,' : ',$h{-foo}; # '-foo : FOO'
[download]

So to be on the safe side one should quote at these points, because if there is a reserved word 'foo' in the future, you will have a problem writing -foo barely.

--
http://fruiture.de

Comment on Re: Re: quoting style for lists Download Code

Replies are listed 'Best First'.
Re: quoting style for lists by Abigail-II (Bishop) on Aug 01, 2002 at 18:00 UTC
`sub bar() { -1 } $_ = -bar; #Ambigous ... as -&bar() ... print; # 1 !not "--1"` [download] Documented! From man perlop: Unary "-" performs arithmetic negation if the operand is numeric. If the operand is an identifier, a string con- sisting of a minus sign concatenated with the identifier is returned. Otherwise, if the string starts with a plus or minus, a string starting with the opposite sign is returned. One effect of these rules is that "-bareword" is equivalent to "-bareword". For fun, let "bar" return `qq {-1}`, and see one of the places in Perl were it matters whether a value is a string or a number. Abigail	[reply] [d/l] [select]
Re: Re: quoting style for lists by fruiture (Curate) on Aug 01, 2002 at 18:14 UTC
clear, because -bar was resolved as - &bar() the minus becomes an Operator and the result depends on what bar() returns. That's what I wanted to express :) -- http://fruiture.de	[reply]