Conway's Game of Life in CoffeeScript

Re:Conway's Game of Life in CoffeeScript by amirshim on Tuesday May 17, 2011 @01:04AM (#2555339)

I love CoffeeScript, except that it makes me hate writing javascript code now :) Thanks @jashkenas for an amazing language.

I personally like code like this:

  countNeighbors: (cell) ->
    neighbors = 0
    neighbors += @isAlive cell.row+x, cell.col+y for x in [-1..1] when x || y for y in [-1..1]
    neighbors 
  isAlive: (row, col) -> if @world[row] and @world[row][col] and @world[row][col].live then 1 else 0

but you have to be careful, since putting a space before the "+x" will cause some bad stuff to happen. Maybe I shouldn't drop so many parenthesis.

@jashkenas can you fix [-10..10] (constant boundary) loops to not check for increasing/decreasing :) I can't think of an edge case that breaks it.

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Re:Conway's Game of Life in CoffeeScript by jacobolus on Tuesday May 17, 2011 @01:50AM (#2555435)

If you add a space after the + also, it’ll be fine (indeed, better).

But to be honest, I hate code that tries to do 5 bits of logic on one 100-character-long line, instead of just breaking into two more readable lines. [Edit: looks like that was fixed in the version at http://willbailey.name/conway/docs/conway.html]

Also, can’t your isAlive function look like:

  isAlive: (row, col) -> @world[row]?[col]?.live

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Re:Conway's Game of Life in CoffeeScript by jashkenas on Tuesday May 17, 2011 @07:47AM (#2556063)

@amirshim:

Yes, range comprehensions were recently optimized to remove direction-checking when possible. On CoffeeScript master ...

    x for x in [-10..10]

... compiles into:

    var x;
    for (x = -10; x <= 10; x++) {
      x;
    }

Even if the start/end values are variables, the check can be avoided by specifying the step as a number. It'll go out with the next release.

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Re:Conway's Game of Life in CoffeeScript by amirshim on Tuesday May 17, 2011 @11:18AM (#2556596)

great!

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