The following is now allowed:
o =
a: 1
b: 2
"#{'c'}": 3
"#{'d'}": 4
e: 5
"#{'f'}": 6
g: 7
It compiles to:
o = (
obj = {
a: 1,
b: 2
},
obj["" + 'c'] = 3,
obj["" + 'd'] = 4,
obj.e = 5,
obj["" + 'f'] = 6,
obj.g = 7,
obj
);
- Closes#3039. Empty interpolations in object keys are now _supposed_ to be
allowed.
- Closes#1131. No need to improve error messages for attempted key
interpolation anymore.
- Implementing this required fixing the following bug: `("" + a): 1` used to
error out on the colon, saying "unexpected colon". But really, it is the
attempted object key that is unexpected. Now the error is on the opening
parenthesis instead.
- However, the above fix broke some error message tests for regexes. The easiest
way to fix this was to make a seemingly unrelated change: The error messages
for unexpected identifiers, numbers, strings and regexes now say for example
'unexpected string' instead of 'unexpected """some #{really long} string"""'.
In other words, the tag _name_ is used instead of the tag _value_.
This was way easier to implement, and is more helpful to the user. Using the
tag value is good for operators, reserved words and the like, but not for
tokens which can contain any text. For example, 'unexpected identifier' is
better than 'unexpected expected' (if a variable called 'expected' was used
erraneously).
- While writing tests for the above point I found a few minor bugs with string
locations which have been fixed.
- Invalid `\x` and `\u` escapes now throw errors.
- U+2028 and U+2029 (which JavaScript treats as newline characters) are now
escaped to `\u2028` and `\u2029`, respectively.
- Octal escapes are now forbidden not only in strings, but in regexes as well.
- `\0` escapes are now escaped if needed (so that they do not form an octal
literal by mistake). Note that `\01` is an octal escape in a regex, while `\1`
is a backreference. (Added a test for backreferences while at it.)
- Fixed a bug where newlines in strings weren't removed if preceded by an
escaped character.
As discussed in https://github.com/jashkenas/coffeescript/issues/3039#issuecomment-68916918.
This is the first step to implement dynamic object literal keys (see #3597).
This also fixes#1392.
In short, `super` is now allowed:
# in class definitions:
class A
instanceMethod: -> super
@staticMethod: -> super
@staticMethod2 = -> super
# in assignment where the next to last access is 'prototype':
A::m = -> super
A.prototype.m = -> super
a.b()[5]::m = -> super
A::[x()] = -> super
class B
@::m = -> super
The following two lines might seem equivalent:
for n in [1, 2, 3] by a then a = 4; n
for n in [1, 2, 3] by +a then a = 4; n
But they used not to be, because `+a` was cached into a `ref`, while the plain
`a` wasn’t. Now even simple identifiers are cached, making the two lines
equivalent as expected.
Instead of compiling to `"" + + (+"-");`, `"#{+}-"'` now gives an appropriate
error message:
[stdin]:1:5: error: unexpected end of interpolation
"#{+}-"
^
This is done by _always_ (instead of just sometimes) wrapping the interpolations
in parentheses in the lexer. Unnecessary parentheses won't be output anyway.
I got tired of updating the tests in test/location.coffee (which I had enough of
in #3770), which relies on implementation details (the exact amount of tokens
generated for a given string of code) to do their testing, so I refactored them
to be less fragile.
Any variables generated by CoffeeScript are now made sure to be named to
something not present in the source code being compiled. This way you can no
longer interfere with them, either on purpose or by mistake. (#1500, #1574)
For example, `({a}, _arg) ->` now compiles correctly. (#1574)
As opposed to the somewhat complex implementations discussed in #1500, this
commit takes a very simple approach by saving all used variables names using a
single pass over the token stream. Any generated variables are then made sure
not to exist in that list.
`(@a) -> a` used to be equivalent to `(@a) -> @a`, but now throws a runtime
`ReferenceError` instead (unless `a` exists in an upper scope of course). (#3318)
`(@a) ->` used to compile to `(function(a) { this.a = a; })`. Now it compiles to
`(function(_at_a) { this.a = _at_a; })`. (But you cannot access `_at_a` either,
of course.)
Because of the above, `(@a, a) ->` is now valid; `@a` and `a` are not duplicate
parameters.
Duplicate this-parameters with a reserved word, such as `(@case, @case) ->`,
used to compile but now throws, just like regular duplicate parameters.
Allow the `by c` part in `for [a..b] by c then`.
Continue disallowing a `when d` part, since it makes no sense having a guard
that isn't given access to anything that changes on every iteration.
A regex may not follow a specific set of tokens. These were already known before
in the `NOT_REGEX` and `NOT_SPACED_REGEX` arrays. (However, I've refactored them
to be more correct and to add a few missing tokens). In all other cases (except
after a spaced callable) a slash is the start of a regex, and may now start with
a space or an equals sign. It’s really that simple!
A slash after a spaced callable is the only ambigous case. We cannot know if
that's division or function application with a regex as the argument. The
spacing determines which is which:
Space on both sides:
- `a / b/i` -> `a / b / i`
- `a /= b/i` -> `a /= b / i`
No spaces:
- `a/b/i` -> `a / b / i`
- `a/=b/i` -> `a /= b / i`
Space on the right side:
- `a/ b/i` -> `a / b / i`
- `a/= b/i` -> `a /= b / i`
Space on the left side:
- `a /b/i` -> `a(/b/i)`
- `a /=b/i` -> `a(/=b/i)`
The last case used to compile to `a /= b / i`, but that has been changed to be
consistent with the `/` operator. The last case really looks like a regex, so it
should be parsed as one.
Moreover, you may now also space the `/` and `/=` operators with other
whitespace characters than a space (such as tabs and non-breaking spaces) for
consistency.
Lastly, unclosed regexes are now reported as such, instead of generating some
other confusing error message.
It should perhaps also be noted that apart from escaping (such as `a /\ b/`) you
may now also use parentheses to disambiguate division and regex: `a (/ b/)`. See
https://github.com/jashkenas/coffeescript/issues/3182#issuecomment-26688427.
Before commit c056c93e `Op::isComplex()` used to return true always. As far as I
understand, that commit attempts to exclude code such as `+1` and `-2` from
being marked as complex (and thus getting cached into `_ref` variables
sometimes). CoffeeScript is supposed to generate readable output so that choice
is understandable. However, it also excludes code such as `+a` (by mistake I
believe), which can cause `a` to be coerced multiple times. This commit fixes
this by only excluding unary + and - ops followed by a number.
It is possible to match only valid JavaScript identifiers with a really long
regex (like coco and CoffeeScriptRedux does), but CoffeeScript uses a much
simpler one, which allows a bit too much.
Quoting jashkenas/coffeescript#1718 #issuecomment-2152464 @jashkenas:
> But it still seems very much across the "worth it" line. You'll get the
> SyntaxError as soon as it hits JS, and performance aside -- even the increase
> in filesize for our browser coffee-script.js lib seems too much, considering
> this is something no one ever does, apart from experimentation.
In short, CoffeeScript treats any non-ASCII character as part of an identifier.
However, unicode spaces should be excluded since having blank characters as part
of a _word_ is very confusing. This commit does so, while still keeping the
regex really simple.
Previously such errors pointed at the end of the input, which wasn't very
helpful. This is also consistent with unclosed strings, where the errors point
at the opening quote.
Note that this includes unclosed #{ (interpolations).
