| To: | rakudobug [...] perl.org |
| Subject: | [LTA] Multi-dimensional Hash subscripts return a List even when indexing a single element |
| From: | "Sam S." <smls75 [...] gmail.com> |
| Date: | Tue, 7 Mar 2017 16:09:27 +0100 |
When using a multi-dimensional Hash subscript of the form `.{ ; }` the
result is always returned as a List (as if taking a slice), even if
the subscript for each dimension is scalar:
my %hash = a => {b => 2, c => 4};
say %hash{"a"}{"b"}.perl; # 2
say %hash{"a";"b"}.perl; # (2,)
That doesn't seem logical, and is also inconsistent with multi-dimensional
*Array* subscripts:
my @array = 0, [0, 0, 42];
say @array[1][2].perl; # 42
say @array[1;2].perl; # 42
On the other hand, the design docs don't have much to offer on the subject...
- https://design.perl6.org/S09.html#Hashes -- Shows how to *statically
declare* multi-dimensional Hashes (NYI in Rakudo), but not how to
index them.
- https://design.perl6.org/S09.html#User-defined_array_indexing --
Shows mutli-dimensional associative indexing, but not for Hashes but
rather for *Arrays with user-defined indices* (NYI in Rakudo).