Comments and extra lines in if...else blocks

[TrevorBurnham]

Here's an odd edge case: The following pointless but well-documented piece of code compiles just fine

# Set i = 1 if true
if true
  i = 1

else
  i = 2

as does this

# Set i = 1 if true
if true
  i = 1
# Otherwise, set i = 2
else
  i = 2

but this won't parse:

# Set i = 1 if true
if true
  i = 1

# Otherwise, set i = 2
else
  i = 2

[TrevorBurnham]

Here's a related parse error:

if true
  alert 'All is well'

parses just fine (unfortunately for the user), but

if true
  ###
    Superfluous comment
  ###
  alert 'All is well'

does not.

[jashkenas]

After taking a couple failed attempts at solving this cleanly, I've settled on a rather unsatisfactory patch that fixes it:

http://github.com/jashkenas/coffee-script/commit/d9071a80a046967209e7fb935970024d66916bfc

Unhappily enough, comments are the single language feature that is the most difficult to parse in CoffeeScript, largely because they can appear in almost any location within the syntax tree. If anyone can come up with a better scheme for handling them ... it would greatly benefit the codebase.

Closing the ticket.

[GeoffreyBooth]

if (true) {
  /*
    Superfluous comment
  */
  alert('All is well');
}

is output now, via #4572. Sorry it took awhile.