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improvements

Adam Roben edited this page · 22 revisions

Size / Speed

$ git log -1 --oneline
79492aa CoffeeScript 1.3.3

$ ls -sk extras/co*.js
176 extras/coffee-script.js

$ cake loc
2659

$ cake bench
Lex     1520 ms (24184 tokens)
Rewrite  186 ms (26925 tokens)
Parse    368 ms
Compile  285 ms (149588 chars)
total   2359 ms
$ git log -1 --oneline
dcff170 0.7.2

$ ls -sk extras/co*.js
160 extras/coco.js

$ coke loc
2499

$ coke bench
Lex      469 ms (26005 tokens)
Rewrite  200 ms (31203 tokens)
Parse    539 ms (26737 nodes)
Compile  341 ms (174118 chars)
TOTAL   1549 ms

Temporary Variables

Coco uses them more wisely than Coffee, making generated code cleaner and/or faster.

$ coffee -bce '[i for i in a]'
// Generated by CoffeeScript 1.3.3
var i;

[
  (function() {
    var _i, _len, _results;
    _results = [];
    for (_i = 0, _len = a.length; _i < _len; _i++) {
      i = a[_i];
      _results.push(i);
    }
    return _results;
  })()
];
$ coco -bce '[i for i of a]'
var i;
[(function(){
  var __i, __ref, __len, __results = [];
  for (__i = 0, __len = (__ref = a).length; __i < __len; ++__i) {
    i = __ref[__i];
    __results.push(i);
  }
  return __results;
}())];
$ coffee -bce 'a > b() > c; d > e() > f'
// Generated by CoffeeScript 1.3.3
var _ref, _ref1;

(a > (_ref = b()) && _ref > c);

(d > (_ref1 = e()) && _ref1 > f);
$ coco -bce 'a > b() > c; d > e() > f'
var __ref;
a > (__ref = b()) && __ref > c;
d > (__ref = e()) && __ref > f;
$ coffee -bce 'r = for k of o then arguments'
// Generated by CoffeeScript 1.3.3
var k, r;

r = (function() {
  var _results;
  _results = [];
  for (k in o) {
    _results.push(arguments);
  }
  return _results;
}).apply(this, arguments);
$ coco -bce 'r = for k in o then arguments'
var k, r, __res, __i, __ref, __len;
__res = [];
for (__i = 0, __len = (__ref = o).length; __i < __len; ++__i) {
  k = __ref[__i];
  __res.push(arguments);
}
r = __res;

Compile Errors

variable safety

$ coffee -bce 'Math += 1'
// Generated by CoffeeScript 1.3.3

Math += 1;

$ coco -bce 'Math += 1'
SyntaxError: assignment to undeclared variable "Math" on line 1

duplicate property

$ coffee -bce '{0, "0"}'
    // Generated by CoffeeScript 1.3.3

    ({
      0: 0,
      "0": "0"
    });

    $ coco -bpe 'a:1, a:2'
    SyntaxError: duplicate property "0" on line 1

line number

$ coffee -bce 'x = (return)'
SyntaxError: cannot use a pure statement in an expression.
...

$ coco -bce 'x = (return)'
SyntaxError: inconvertible statement on line 1
...

`

space/tab contamination

$ cat space_tab.coffee
if 0
        console.log 1
        console.log 2

$ coffee space_tab.coffee
2

$ coco space_tab.coffee
Failed at: space_tab.coffee

SyntaxError: contaminated indent %09 on line 2

misdentation

    $ cat misdent.coffee
    if 0
        console.log 1
      console.log 2

    $ coffee misdent.coffee
    2

    $ coco misdent.coffee
    Failed at: misdent.coffee

    SyntaxError: unmatched dedent (2 for 4) on line 3

invalid call

    $ coffee -bce '[]()'
    // Generated by CoffeeScript 1.3.3

    []();

    $ coco -bce '[]()'
    SyntaxError: invalid callee on line 1

invalid regex

    $ coffee -bce '/+/'
    // Generated by CoffeeScript 1.3.3

    /+/;

    $ coco -bce '/+/'
    SyntaxError: Invalid regular expression: /+/: Nothing to repeat on line 1

invalid identifier

    $ coffee -bce '$= 1'
    // Generated by CoffeeScript 1.3.3
    var $;

    $ = 1;

    $ coco -bce '$= 1'
    Error: Parse error on line 1: Unexpected ''

    $ node -e '$= 1'

    undefined:1

    ^
    SyntaxError: Unexpected token ILLEGAL

invalid operand

    $ coffee -bce '0 instanceof 1'
    // Generated by CoffeeScript 1.3.3

    0 instanceof 1;

    $ coco -bce '0 instanceof 1'
    SyntaxError: invalid instanceof operand on line 1

    $ node -e '0 instanceof 1'

    undefined:1

    ^
    TypeError: Expecting a function in instanceof check, but got 0

Syntax Consistency

@foothis.foo

$ coffee -bce '{@foo}'
// Generated by CoffeeScript 1.3.3

({
  foo: this.foo
});

$ coffee -bce '{this.foo}'
Error: Parse error on line 1: Unexpected 'THIS'
...
$ coco -bce '{@foo}; {this.foo}'
({
  foo: this.foo
});
({
  foo: this.foo
});

implicit call/object interaction

$ coffee -bce 'f k: v, a + b'
Error: Parse error on line 1: Unexpected '+'
...


$ coffee -bce 'k: f a, ->'
Error: Parse error on line 1: Unexpected ','
...
$ coco -bce 'f k: v, a + b'
f({
  k: v
}, a + b);

$ coco -bce 'k: f a, ->'
({
  k: f(a, function(){})
});
$ coffee -bcs
  f
    k: v
    a

// Generated by CoffeeScript 1.3.3

f({
  k: v
}, a);

$ coffee -bcs
  f
    a
    k: v

Error: Parse error on line 2: Unexpected 'INDENT'
...
$ coco -bcs
  f do
    k: v
    a

f({
  k: v
}, a);

$ coco -bcs
  f do
    a
    k: v

f(a, {
  k: v
});

line continuation

$ coffee -bcs
  if a then b
       else c

Error: Parse error on line 1: Unexpected 'INDENT'
...
$ coco -bcs
  if a then b
       else c

if (a) {
  b;
} else {
  c;
}
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