When "take" is called on a variable that is later modified, is the
Capture returned by the enclosing "gather" supposed to reflect the
change or not? I know that Captures are the Perl 6 equivalent of
references, but it seems natural to expect the contents to be copied
by value at some point prior to the variables being modified.
As an example, what is the output of the below program supposed to
be? On Rakudo (which doesn't seem to support multidimensional
captures properly), it's "[20, 21, 22, 20, 21, 22, 20, 21, 22, 20, 21,
22]" instead of the desired "[[0, 1, 2, 3, 4], [5, 6, 7, 8, 9], [10,
11, 12, 13, 14], [15, 16, 17, 18, 19]]". I could get around this
problem by copying the variable before "take"-ing it, e.g., writing
"take [ @things ]" instead of "take @things"; likewise, when writing
similar code that "take"s string variables, copying could be performed
by enclosing the variable in double quotes. However, for more complex
datatypes, is there an easier (i.e., shorter) copying mechanism than
assigning the value to a new variable that is scoped to the current
block? Is this even necessary, i.e., is the observed behavior just a
bug in Rakudo, or is that too much to hope for?
#!/usr/bin/env perl6
use v6;
my @stuff = gather {
my @things;
for ^23 {
@things.push: $_;
if @things == 5 {
take @things;
@things = ();
}
}
}
say @stuff.perl;
__END__
-- Minimiscience
