holli
asked on
how to make a function lvalue?
hi experts.
some functions in perl can be lvalue. eg. substr.
$foo=substr($bar,1,2); #rvalue
substr($bar,1,2)=$foo; #lvalue
how can i mimic this behaviour in a self-written perl-function?
some functions in perl can be lvalue. eg. substr.
$foo=substr($bar,1,2); #rvalue
substr($bar,1,2)=$foo; #lvalue
how can i mimic this behaviour in a self-written perl-function?
sorry, that was about the worst example I could ever give...
try this:
@arr=qw/one two three four/;
sub ref2 : lvalue
{
$pt=shift;
for($i=0;$i<scalar @$pt;$i++)
{
if($pt->[$i]=~/three/)
{
$po=$i;
}}
$pt->[$po];
}
print $arr[2] . "\n";
ref2(\@arr)="eighteen";
print $arr[2];
try this:
@arr=qw/one two three four/;
sub ref2 : lvalue
{
$pt=shift;
for($i=0;$i<scalar @$pt;$i++)
{
if($pt->[$i]=~/three/)
{
$po=$i;
}}
$pt->[$po];
}
print $arr[2] . "\n";
ref2(\@arr)="eighteen";
print $arr[2];
ASKER
ASKER
so i need a global variable?
that's bad. i wanted to implement something like this:
package foo;
sub new { return bless ( {}, shift ); }
sub property : lvalue
{ my $this=shift; my $prop=shift;
$this->{$prop}=lvalue if lvalue;
return $this->$prop
}
1;
----
use foo;
my $f=foo->new();
$f->property("color")="red
print $f->property("color"); #->red
is there a way to do that?
that's bad. i wanted to implement something like this:
package foo;
sub new { return bless ( {}, shift ); }
sub property : lvalue
{ my $this=shift; my $prop=shift;
$this->{$prop}=lvalue if lvalue;
return $this->$prop
}
1;
----
use foo;
my $f=foo->new();
$f->property("color")="red
print $f->property("color"); #->red
is there a way to do that?
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something like
@arr=qw/one two three four/;
sub ref : lvalue
{
$pt=shift;
for($i=0;$i<4;$i++)
{
if($pt->[$i]=="three")
{
$po=$i;
}}
$pt->[$po];
}
print $arr[3];
ref(\@arr)="eighteen";
print $arr[3];