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Re^3: implementing a scrabble-esque game on Termux III

by tybalt89 (Prior)
on Nov 23, 2019 at 22:50 UTC ( #11109126=note: print w/replies, xml ) Need Help??


in reply to Re^2: implementing a scrabble-esque game on Termux III
in thread implementing a scrabble-esque game on Termux III

$board =~ /(?<!\w).{2,}(?!\w)(?{ push @pat, [ $-[0], $& ] })(*FAIL)/ +;

This is the heart of finding a place to move. For a word to be a legal move, it must match one of the patterns in @pat. The (?<!\w) prevents putting the new word next to a preceding word, and the (?!\w) prevent putting the new word abutting a following word. The(*FAIL) forces the regex engine to try every possible place to find a match.

Try

perl -le ' "abcd" =~ /.{2,}(?{print $&})(*FAIL)/ '

and notice it prints out every substring with two or more characters.

Replies are listed 'Best First'.
Re^4: implementing a scrabble-esque game on Termux III and Path::Tiny output
by Aldebaran (Deacon) on Dec 03, 2019 at 06:53 UTC

    leaving vertical space for respondents...

    Thanks for your comment,

      Explanation of the masking in "matchrule"

      sub matchrule { my ( $old, $highs, $word ) = @_; $old eq $word and return 0; my $newmask = ( $old ^ $word ) =~ tr/\0/\xff/cr; ( $newmask & $highs ) =~ tr/5// and return 0; my $tiles = "@tiles"; $tiles =~ s/$_// or return 0 for ( $newmask & $word ) =~ /\w/g; return 1; }

      Let's follow a call to matchrule('hello', '14222', 'world')

      First off, if old and word are the same, it's not a valid move.

      Next, get the mask. ( note: strings have been printed by Data::Dumper::Useqq = 1 )

      'hello' ^ 'world' => "\37\n\36\0\13"

      However, I want to change all non nulls ("\0") to "\xff" so that characters can pass through these positions unchanged.

      my $newmask = ('hello' ^ 'world') =~ tr/\0/\xff/cr => "\377\377\377\0\ +377"

      Now we use this mask against the tile heights and look for any 5's, because the "\xff" in $newmask are at the positions where new tiles will be added.

      ("\377\377\377\0\377" & '14222') => "142\0002"

      and since there is no 5, the new word is not invalid (yet).

      "\377\377\377\0\377" & 'world' => "wor\0d"

      This leaves only the new tiles that must be played, ignoring the "\0" because those positions use the old tile. So remove each new letter from a string of the tile rack, and if any are not there, the move is invalid.

      Hope this helps.

      my $newmask = ( $old ^ $word ) =~ tr/\0/\xff/cr; $flip and ( $board, $heights ) = flip $board, $heights; substr $board, $pos, length $word, $word; #say "new mask is $newmask"; substr $heights, $pos, length $highs, ( $highs & $newmask ) =~ tr/0-4/1-5/r | ( $highs & ~$newmask ); $flip and ( $board, $heights ) = flip $board, $heights; my $tiles = join '', @tiles; say "word is $word"; $tiles =~ s/$_// for split //, $word & $newmask;

      let me try...

      my $newmask = ( $old ^ $word ) =~ tr/\0/\xff/cr;

      $newmask is "\xff" where the old and new words differ, that is a new tile must be used. It is "\0" where no tile is to be placed (using existing board state).

      $flip and ( $board, $heights ) = flip $board, $heights; substr $board, $pos, length $word, $word; #say "new mask is $newmask"; # $newmask has unprintable characters +, use something like Data::Dump that will show them. substr $heights, $pos, length $highs, ( $highs & $newmask ) =~ tr/0-4/1-5/r | ( $highs & ~$newmask );

      hehehe! GOAL => increment the stack sizes for only the new tiles.

      $highs & $newmask produces a string that only has non-null characters where new tiles are to be played. In other words, it isolates the stacks for the new tiles, everywhere else is "\0".
      =~ tr/0-4/1-5/r increments the height for each place a new tile is played.
      ~$newmask inverts $newmask to be "\xff" only where old tiles remain visible.
      $highs & ~$newmask produces a string with only the unchanged stack values (and "\0" where the new values are).
      Finally, the | puts the old and new stack counts together so they can be replaced in the heights string.

      $flip and ( $board, $heights ) = flip $board, $heights; my $tiles = join '', @tiles; say "word is $word"; $tiles =~ s/$_// for split //, $word & $newmask;

      This removes the tiles that are used for this word from the string of all tiles, soon to be replaced in @tiles.

      Hope this helps...

        Hope this helps...

        It does. I was able to see these masks by unpacking them as hexidecimal. Here's a bit of output:

        Fishing for tips. Thanks for your comment,

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