Your code which wraps tie in @{ ... } does not work because all elements are FETCH-ed first before the loop block code is executed. I.e. in the above case, FETCH(0) and FETCH(1) are called before "first" and "second" are print-ed by print(). The @{ ... } basically turns the tied array into list of values. I need to iterate over the tied array so the code in the loop block (in this case, print()) is executed along with FETCH/FETCHSIZE.
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use strict;
use warnings;
package MyClass;
use Tie::Array;
our @ISA = ('Tie::Array');
our @data;
# mandatory methods
sub TIEARRAY { my $class = shift; bless \@data, $class; @data = @_
+; return \@data }
sub FETCH { print "FETCH: "; my ($self, $index ) = @_; return $dat
+a[$index] }
sub FETCHSIZE { print "<FETCHSIZE> "; return scalar @data }
package main;
for( @{ tie my @x, "MyClass", "first", "second"; \@x } ) {
print "In loop = ";
print "$_\n";
}
Output:
In loop = FETCH: first
In loop = FETCH: second
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Ah sorry, I stand corrected. I was reading your code as:
for( do { tie my @x, "MyClass", "first", "second"; @x } ) {
So indeed:
for( @{ tie my @x, "MyClass", "first", "second"; \@x } ) {
will make for() iterate over a tied array. In fact,
use strict;
use warnings;
package MyClass;
use Tie::Array;
our @ISA = ('Tie::Array');
our @data;
# mandatory methods
sub TIEARRAY { my $class = shift; bless \@data, $class; @data = @_
+; return \@data }
sub FETCH { print "FETCH: "; my ($self, $index ) = @_; return $dat
+a[$index] }
sub FETCHSIZE { return scalar @data }
package main;
sub wrapper {
tie my @x, "MyClass", @_;
\@x;
}
for( @{wrapper("first", "second")} ) {
print "In loop = ";
print "$_\n";
}
also works. So it's quite close to what I want, yay. Any improvement is welcome :-)
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