%h«$x» is a trap

[AlexDaniel]

I've never seen this before, and I'm actually surprised that somebody came up with this (edit: actually, our docs suggested it).

Code:

my %h = ‘hello’ => 42;
my $x = ‘hello’;
say %h«$x»

Result:

42

So it works, right? Wrong.

Code:

my %h = ‘hello world’ => 42;
my $x = ‘hello world’;
say %h«$x»

Result:

((Any) (Any))

Of course, the right way to do it is to use %h{$x}. If you insist on «» for some reason, then %h«“$x”».

See this: https://irclog.perlgeek.de/perl6/2017-06-07#i_14699923

[AlexDaniel]

OK, this is a pitfall, because our docs are full of this:

doc/Language/5to6-nutshell.pod6:    say %calories«$key»;  # Perl 6 - double angles interpolate as a list of Str
doc/Language/5to6-nutshell.pod6:    say join ',', %calories«$keys»;          # Perl 6 the split is done after interpolation
doc/Language/operators.pod6:    say %color«cherry $fruit».perl;   # OUTPUT: «("red", "green")␤»
doc/Language/rb-nutshell.pod6:    say %calories«$key»;    # Perl 6 - double angles interpolate as double-quotes
doc/Language/rb-nutshell.pod6:    say %calories«$keys».join(','); # Perl 6, interpolated split
doc/Language/subscripts.pod6:    %hash«foo $var»;    # same as %hash{ «foo $var» }
doc/Type/Hash.pod6:    dd %h«oranges $fruit»;