trans.p6

use v6;

use Test;

use MONKEY_TYPING;
augment class Str {
    method trans(*@patterns)  {
		my %replacements;
		my @pat;
		for @patterns -> $pair {
			
			#null string on the right 
			if $pair.value.comb.elems == 0 {
				for $pair.key.comb -> $a
				{
					@pat.push($a, Mu);
				}
				next;
			}
			#smaller right string
			elsif $pair.key.comb.elems > $pair.value.comb.elems {
				$pair.value ~= $pair.value.comb[-1] x
							($pair.key.comb.elems - $pair.value.comb.elems);
			}

			#http://irclog.perlgeek.de/perl6/2010-06-03#i_2400803 workaround
			@pat.push( (eager $pair.key.comb) Z $pair.value.comb);
		}
		%replacements = @pat ;
		say %replacements.perl ;
		my $res = '';
		for self.comb -> $char {
			if %replacements.exists($char) { 
				#say $char;
				$res ~= %replacements{$char} if %replacements{$char}.defined;
			}
			else { $res ~= $char }
		}
		#say $res;
		return $res;
        #'wrong return value';
    }
}

plan *;

is("ABC".trans( ('A'=>'a'), ('B'=>'b'), ('C'=>'c') ),
	"abc",
	"Each side can be individual characters");

is("XYZ".trans( ('XYZ' => 'xyz') ),
	"xyz",
	"The two sides of the any pair can be strings interpreted as tr/// would multichar");

is("XYa".trans( ('XYZ' => 'xyz') ),
	"xya",
	"Not all chars match");

is("abc".trans( ("abc" => "AB") ),
	"ABB",
	"Right hand too short");

is("abcd".trans( ("abc" => "") ),
	"d",
	"No right hand");
is("eabcd".trans( ("abc" => "") , ('e'=>'E')),
	"Ed",
	"No right hand in multiple pairs");

is("abcd".trans( ("abc" => "ABZ"), ('c' => 'C') ),
	"ABCd",
	"overlapping transliterations");

#...
# ranges should use the flipflop operator?
# using arrays isn't done yet.

done_testing;