Mr_Micawber has asked for the wisdom of the Perl Monks concerning the following question:

I've been experimenting with using interpolated strings to define hashes. I'm curious why the variation defining %kv below works. There's something about the colon, which I think is a pair constructor (?) and the square brackets that I'm not getting. 

#!/usr/bin/perl6

use v6;

my ($hkey, $hval ) = <somekey someval>;

# simple form:
#  my %kv = $hkey, $hval;   # works

my %kv = :[$hkey],$hval;    # works

#  my %kv = :$hkey,$hval;   # error
#  my %kv = :{$hkey},$hval; # _block83 someval

say %kv; # somekey someval

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Re: Perl 6, defining a hash with interpolated string
by molecules (Monk) on Aug 04, 2010 at 17:43 UTC
    I'm not really sure, but it seems that the colon is effectively ignored in that context. Try the following: 
    use v6; 

my $item = :[:[:[$hkey]]];
say $item.perl;           # outputs [[["somekey"]]]

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[d/l]

      I think I was looking for the interpolating analog of this model for specifying a literal hash pair:

      %kv = :LiteralKey<LiteralValue>

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[d/l]
        The last two of the following examples give you interpolation, but it is more of the "normal" interpolation you would expect in Perl. 
        use v6;


my %kv1 = :LiteralKey<LiteralValue>;

say :%kv1.perl;



my %kv2 = <LiteralKey>,<LiteralValue>;

say :%kv2.perl;



my $var3 = 'Literal';
my %kv3  = "{$var3}key",'LiteralValue';

say :%kv3.perl;



my $var4 = 'LiteralKey';
my %kv4  = "$var4",'LiteralValue';

say :%kv4.perl;

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        gives you 
        "kv1" => {"LiteralKey" => "LiteralValue"}
"kv2" => {"LiteralKey" => "LiteralValue"}
"kv3" => {"Literalkey" => "LiteralValue"}
"kv4" => {"LiteralKey" => "LiteralValue"}

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