Lazy K in CoffeeScript

lazyk.coffee

lazy = (x) -> () -> x
thaw = (x) -> x()
app = () -> [].slice.call(arguments, 0).reduce (x, y) -> () -> thaw(x)(y)

S = (x) -> (y) -> (z) -> thaw app(x, z, app(y, z))
K = (x) -> (y) -> thaw x
I = (x) -> thaw x

parseLazyK = (source) ->
  stack = [[]]

  while source
    c = source[0]
    source = source[1..-1]

    switch c
      when 's'
        stack[0].push S
      when 'k'
        stack[0].push K
      when 'i'
        stack[0].push I
      when '`'
        stack.unshift []

    while stack.length > 1 && stack[0].length > 1
      x = stack.shift()
      stack[0].push x

  stack[0]

execLazyK = (node) ->
  tmp = node.map (x) ->
    if x instanceof Array
      execLazyK x
    else
      lazy x
  tmp.reduce (x, y) -> app x, y

evalLazyK = (source) -> execLazyK parseLazyK source

LazyK = (source, input) ->
  program = evalLazyK source
  output = app program, strToScottList(input)
  js_output = scottListToStr output
  console.log thaw js_output

churchNatToInt = (x) -> app x, lazy((x) -> thaw(x) + 1), lazy(0)
churchNatToStr = (x) -> lazy String.fromCharCode thaw churchNatToInt x
scottListToStr = (xs) -> app xs, lazy((h) -> (t) -> if (thaw churchNatToInt h) > 255 then "" else (thaw churchNatToStr h) + (thaw scottListToStr t))

intToChurchNat = (i) -> lazy((f) -> (x) ->
                                j = i
                                y = x
                                while j != 0
                                  y = app f, y
                                  j = j - 1
                                thaw y)
strToChurchNat = (s) -> intToChurchNat s.charCodeAt 0
strToScottList = (s) ->
  if s
    lazy((f) -> thaw app(f, strToChurchNat(s[0]), strToScottList(s[1..-1])))
  else
    lazy((f) -> thaw app(f, intToChurchNat(256), strToScottList("")))

@LazyK = LazyK
@LazyK.parse = parseLazyK
@LazyK.eval = evalLazyK
@LazyK.helloworld = "`k``s``si`k``s`k```sii``s``s`kski``s``s`ksk``s``s`ksk```s``siii``s``s`kski`k``s``si`k``s``s`ksk```s``s`kski``s`k``s``s`kski``s``s`ksk```sii``s``s`kski`k``s``si`k``s`k```sii``s``s`kski```sii``s``s`ksk``s``s`kski`k``s``si`k``s`k```sii``s``s`kski```sii``s``s`ksk``s``s`kski`k``s``si`k``s``s`ksk``s`k``s``s`kski``s``s`ksk``s`k``s``s`kski```sii``s``s`ksk``s``s`kski`k``s``si`k````s``s`ksk```s``siii``s``s`kski`s``s`ksk```sii``s``s`ksk``s``s`kski`k``s``si`k``s`k``s``s`kski```s``siii``s``s`kski`k``s``si`k``s`k``s``s`ksk``s`k``s``s`kski``s``s`ksk``s``s`kski``s``s`ksk```s``siii``s``s`kski`k``s``si`k``s``s`ksk``s`k``s``s`kski``s``s`ksk``s`k``s``s`kski```sii``s``s`ksk``s``s`kski`k``s``si`k``s`k``s``s`kski``s``s`ksk``s`k``s``s`kski``s``s`ksk```sii``s``s`ksk``s``s`kski`k``s``si`k``s`k```sii``s``s`kski```sii``s``s`ksk``s``s`kski`k``s``si`k```s``s`kski``s`k``s``s`kski``s``s`ksk```sii``s``s`kski`k``s``si`k``s``s`ksk``s`k``s``s`kski```s``siii``s``s`kski`k``s``si`k``s`k``s``s`kski``s``s`ksk```sii``s``s`kski`k``s``si`k```sii```sii``s``s`kski`k```sii```sii``s``s`kski"

lazyk.js

// Generated by CoffeeScript 1.3.3
(function() {
  var I, K, LazyK, S, app, churchNatToInt, churchNatToStr, evalLazyK, execLazyK, intToChurchNat, lazy, parseLazyK, scottListToStr, strToChurchNat, strToScottList, thaw;

  lazy = function(x) {
    return function() {
      return x;
    };
  };

  thaw = function(x) {
    return x();
  };

  app = function() {
    return [].slice.call(arguments, 0).reduce(function(x, y) {
      return function() {
        return thaw(x)(y);
      };
    });
  };

  S = function(x) {
    return function(y) {
      return function(z) {
        return thaw(app(x, z, app(y, z)));
      };
    };
  };

  K = function(x) {
    return function(y) {
      return thaw(x);
    };
  };

  I = function(x) {
    return thaw(x);
  };

  parseLazyK = function(source) {
    var c, stack, x;
    stack = [[]];
    while (source) {
      c = source[0];
      source = source.slice(1);
      switch (c) {
        case 's':
          stack[0].push(S);
          break;
        case 'k':
          stack[0].push(K);
          break;
        case 'i':
          stack[0].push(I);
          break;
        case '`':
          stack.unshift([]);
      }
      while (stack.length > 1 && stack[0].length > 1) {
        x = stack.shift();
        stack[0].push(x);
      }
    }
    return stack[0];
  };

  execLazyK = function(node) {
    var tmp;
    tmp = node.map(function(x) {
      if (x instanceof Array) {
        return execLazyK(x);
      } else {
        return lazy(x);
      }
    });
    return tmp.reduce(function(x, y) {
      return app(x, y);
    });
  };

  evalLazyK = function(source) {
    return execLazyK(parseLazyK(source));
  };

  LazyK = function(source, input) {
    var js_output, output, program;
    program = evalLazyK(source);
    output = app(program, strToScottList(input));
    js_output = scottListToStr(output);
    return console.log(thaw(js_output));
  };

  churchNatToInt = function(x) {
    return app(x, lazy(function(x) {
      return thaw(x) + 1;
    }), lazy(0));
  };

  churchNatToStr = function(x) {
    return lazy(String.fromCharCode(thaw(churchNatToInt(x))));
  };

  scottListToStr = function(xs) {
    return app(xs, lazy(function(h) {
      return function(t) {
        if ((thaw(churchNatToInt(h))) > 255) {
          return "";
        } else {
          return (thaw(churchNatToStr(h))) + (thaw(scottListToStr(t)));
        }
      };
    }));
  };

  intToChurchNat = function(i) {
    return lazy(function(f) {
      return function(x) {
        var j, y;
        j = i;
        y = x;
        while (j !== 0) {
          y = app(f, y);
          j = j - 1;
        }
        return thaw(y);
      };
    });
  };

  strToChurchNat = function(s) {
    return intToChurchNat(s.charCodeAt(0));
  };

  strToScottList = function(s) {
    if (s) {
      return lazy(function(f) {
        return thaw(app(f, strToChurchNat(s[0]), strToScottList(s.slice(1))));
      });
    } else {
      return lazy(function(f) {
        return thaw(app(f, intToChurchNat(256), strToScottList("")));
      });
    }
  };

  this.LazyK = LazyK;

  this.LazyK.parse = parseLazyK;

  this.LazyK["eval"] = evalLazyK;

  this.LazyK.helloworld = "`k``s``si`k``s`k```sii``s``s`kski``s``s`ksk``s``s`ksk```s``siii``s``s`kski`k``s``si`k``s``s`ksk```s``s`kski``s`k``s``s`kski``s``s`ksk```sii``s``s`kski`k``s``si`k``s`k```sii``s``s`kski```sii``s``s`ksk``s``s`kski`k``s``si`k``s`k```sii``s``s`kski```sii``s``s`ksk``s``s`kski`k``s``si`k``s``s`ksk``s`k``s``s`kski``s``s`ksk``s`k``s``s`kski```sii``s``s`ksk``s``s`kski`k``s``si`k````s``s`ksk```s``siii``s``s`kski`s``s`ksk```sii``s``s`ksk``s``s`kski`k``s``si`k``s`k``s``s`kski```s``siii``s``s`kski`k``s``si`k``s`k``s``s`ksk``s`k``s``s`kski``s``s`ksk``s``s`kski``s``s`ksk```s``siii``s``s`kski`k``s``si`k``s``s`ksk``s`k``s``s`kski``s``s`ksk``s`k``s``s`kski```sii``s``s`ksk``s``s`kski`k``s``si`k``s`k``s``s`kski``s``s`ksk``s`k``s``s`kski``s``s`ksk```sii``s``s`ksk``s``s`kski`k``s``si`k``s`k```sii``s``s`kski```sii``s``s`ksk``s``s`kski`k``s``si`k```s``s`kski``s`k``s``s`kski``s``s`ksk```sii``s``s`kski`k``s``si`k``s``s`ksk``s`k``s``s`kski```s``siii``s``s`kski`k``s``si`k``s`k``s``s`kski``s``s`ksk```sii``s``s`kski`k``s``si`k```sii```sii``s``s`kski`k```sii```sii``s``s`kski";

}).call(this);