Grid.pm6

unit class Grid;

#use Terminal::Print::Commands;
#
#constant T = Terminal::Print::Commands;

has @.grid;
has $!character-supply;
has $!control-supply;

has $.max-columns;
has $.max-rows;
has @.grid-indices;

submethod BUILD( :$!max-columns, :$!max-rows ) {
    @!grid-indices = ^$!max-rows X ^$!max-columns;

    for ^$!max-columns -> $x {
        for ^$!max-rows -> $y {
            @!grid[$x;$y] = Str.new(:value(" "));
        }
    }

    $!character-supply = Supply.new;
    $!control-supply = Supply.new;
}

method initialize {
    start {
        react {
            whenever $!character-supply -> [$x,$y,$c] { 
                @!grid[$x;$y] = $c;
            }
            whenever $!control-supply -> $command {
                given $command {
                    # I have a feeling this isn't actually doing what I think it's doing
                    # Probably need to rewrite this whole react block as a Promise
                    # and keep the vow here. Then we can just spin up a new Promise whenever
                    # initialize gets called again, or throw an exception if the current 'React Promise'
                    # is not yet kept.
                    when 'close' { done; }
                }
            }
        }
    }
}

method shutdown {
    $!control-supply.emit('close');
}

method change-cell($x,$y,$c) {
    $!character-supply.emit([$x,$y,$c]);
}

method AT-POS($x,$y) {
    @!grid[$x;$y];
}

method EXISTS-POS($x,$y) {
    @!grid[$x;$y]:exists;
}

method BIND-POS($x,$y,$v) {
    @!grid[$x;$y] := $v;
}

method ASSIGN-POS($x,$y,$v) {
    #    my $v = @coords[*-1];
    say "v:$v,x:$x,y:$y";
    #    self.AT-POS(@coords) = $v;
    @!grid[$x;$y] = $v;
}

grid.t

use v6;

use lib './';
use test;

use Grid;

my $grid;

lives-ok    { $grid = Grid.new(:max-rows(20),:max-columns(10)); dd $grid.grid }, 'Grid survived';
lives-ok    { $grid.initialize; dd $grid.grid }, '$grid.initialize works';
lives-ok    { $grid.change-cell(1,1,'Y') }, '$grid.change-cell works';
ok          $grid[1;1] eq 'Y', 'Inserted value present where expected';
lives-ok    { $grid[0;0] = "X" }, 'Can assign "X" to $grid[0;0]';

lives-ok    { $grid.shutdown }, '$grid.shutdown works';