#! /usr/bin/env false

use v6.c;
use MONKEY-TYPING;

# Don't use precompilation in order to not conflict with other MONKEY-TYPING
# modules.
no precompilation;

augment class Hash
{
    #| Merges a second hash into the hash the method is called on. Hash given as
    #| the argument is not modified.
    #| Traverses the full tree, replacing items in the original hash with the
    #| hash given in the argument. Does not replace positional elements by default,
    #| and instead appends the items from the supplied hash's array to the original
    #| hash's array. The object type of positionals is not retained and instead
    #| becomes an Array type.
    #| Use :no-append-array to replace arrays and positionals instead, which will
    #| also retain the original type and not convert to an Array
    multi method merge (Hash:U: %b, Bool:D :$no-append-array = False) {
        warn "Cannot merge an undefined Hash!";
        return %b;
    }

    multi method merge (Hash:D: %b, Bool:D :$no-append-array = False)
    {
        hashmerge self, %b, :$no-append-array;
    }

    sub hashmerge (%merge-into, %merge-source, Bool:D :$no-append-array)
    {
        for %merge-source.keys -> $key {
            if %merge-into{$key}:exists {
                given %merge-source{$key} {
                    when Hash {
                        hashmerge %merge-into{$key},
                                  %merge-source{$key},
                                  :$no-append-array;
                    }
                    when Positional {
                        %merge-into{$key} = $no-append-array
                            ?? %merge-source{$key}
                            !!
                            do {
                                my @a;
                                @a.push: $_ for %merge-into{$key}.list;
                                @a.push: $_ for %merge-source{$key}.list;
                                @a;
                            }
                    }
                    # Non-positionals, so strings or Bools or whatever
                    default { %merge-into{$key} = %merge-source{$key} }
                }
            } else {
                %merge-into{$key} = %merge-source{$key};
            }
        }
        %merge-into;
    }
}

# vim: ft=perl6 ts=4 sw=4 et