Multiline comments broken if contain code with ###

[7v0lk0v]

> cat test.coffee
###
console.log '### this should be ignored, not compiled'

console.log '### this too'

console.log '####### and this'
###

> bin/coffee -p test.coffee
(function() {
  /*
  console.log '*/
  this(should(be(ignored, !compiled`console.log `)));

  /* this too'
//##

console.log '*/

}).call(this);

Using latest master: 571e9df

[GeoffreyBooth]

This is to be expected. JavaScript works the same way:

/*
console.log('*/ oh no, I’m no longer in the comment!')
*/

Comments are like strings, treated as random characters until the next delimiter is encountered.

[Inve1951]

i was under the impression that coffee took care of this by requiring the opening and closing tag to share the same indentation level. i remember getting indentation errors when commenting out code parts without matching them in my early days with coffee.

[GeoffreyBooth]

@Inve1951 Comments were refactored between 1 and 2, to allow block (###) comments to be inserted anywhere, and to allow line (#) comments to be output into JS. This wasn’t considered a breaking change, because all previously allowed block comments were still allowed in 2; and more cases of block comments became allowed.

However I don’t seem to be able to replicate the “same indentation” requirement you describe. At least in 1.12.7, open and closing ### delimiters don’t seem to need to be at the same level: http://coffeescript.org/v1/#try:%23%23%23%0A%091%0A%09%09%23%23%23. Maybe that was the case in a much older version of CoffeeScript.

[Inve1951]

v2 vs v1
not quite what i described earlier. in v1 the comment opening tag has to be on current indent level or it gives an indent error.

[GeoffreyBooth]

Yeah, that’s to be expected. In v1 block comments could only exist where expressions could, like where you could put a parenthesized block, whereas in v2 they can now exist anywhere.

[Inve1951]

OP's issue is quite the edge case, indeed. however i feel like there could be a clean solution to it. for example escaping the first hashtag with a backslash.
current workaround is to escape every other # like so:

###
console.log '\##\# this should be ignored, not compiled'

console.log '\##\# this too'

console.log '\##\##\##\# and this'
###

edit: just noticed that you can't open block comments inside string literals. so OP's code compiles fine unless commented out.

[GeoffreyBooth]

I think the most reasonable solution is to just use an editor that allows commenting out long selections of text. Almost any editor I’ve used, whether a simple text editor or an IDE, allows you to select multiple lines of text and press Cmd-/ or Ctrl-/ to insert #s at the beginning of the line.

[Inve1951]

neat, learned something new