Legal semicolon at the end of file leads to "unexpected end of input"

[jtmalinowski]

To reproduce:

create a file with following contents:

a = 1
require('./main2');

observe error:

/home/developer/.nvm/v0.8.20/lib/node_modules/commonjs-everywhere/node_modules/coffee-script-redux/lib/module.js:73
      throw new Error(formatParserError(preprocessed, e));
            ^
Error: Syntax error on line 2, column 19: unexpected end of input
    at Object.module.exports.parse (/home/developer/.nvm/v0.8.20/lib/node_modules/commonjs-everywhere/node_modules/coffee-script-redux/lib/module.js:73:13)
    at Object.exports.cjsify.handlers..coffee (/home/developer/.nvm/v0.8.20/lib/node_modules/commonjs-everywhere/lib/index.js:138:50)
    at Object.exports.cjsify (/home/developer/.nvm/v0.8.20/lib/node_modules/commonjs-everywhere/lib/index.js:172:101)
    at Object. (/home/developer/.nvm/v0.8.20/lib/node_modules/commonjs-everywhere/lib/command.js:29:28)
    at Object. (/home/developer/.nvm/v0.8.20/lib/node_modules/commonjs-everywhere/lib/command.js:75:3)
    at Module._compile (module.js:449:26)
    at Object.Module._extensions..js (module.js:467:10)
    at Module.load (module.js:356:32)
    at Function.Module._load (module.js:312:12)
    at Module.require (module.js:362:17)

if you change to

require('./main');
a = 1

it works fine, should show no error for 1. case

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[mehcode]

; is a binary operator in coffee-script. I don't believe @michaelficarra wants it to be able to be used as a null statement but I could be wrong.

[michaelficarra]

Looks fine to me. The semicolon is CoffeeScript's , operator. You wouldn't expect this JavaScript program to work, would you?

a = 1
require('./main2'),

edit: @mehcode just beat me to it.

[jtmalinowski]

ok, my bad. Is original coffee compiler wrong then?

[michaelficarra]

In this case, I'd say it depends who you ask. I have no qualms about not supporting trailing semicolons, though. If that's how you were writing your CoffeeScript code before, you were doing it wrong.

[jtmalinowski]

nope its just that I was re writing some js and forgot to remove the semicolon. browserify was fine with it but commonjs-everywhere not, coffee pushed it but redux not, that confused me. thanks for help

[michaelficarra]

Ah, I see how that could happen. My editor actually points out trailing semicolons in bright red. Well, good luck with commonjs-everywhere!

[mark-hahn]

you were doing it wrong.

In your opinion. The way it is now it will break code for no reason. I personally believe carrying this over from CS is harmless.

On Mon, Mar 4, 2013 at 1:29 PM, Michael Ficarra [email protected]:

Ah, I see how that could happen. My editor actually points out trailing semicolons in bright red. Well, good luck with commonjs-everywhere!

— Reply to this email directly or view it on GitHubhttps://github.com/michaelficarra/CoffeeScriptRedux/issues/174#issuecomment-14406776 .

[epidemian]

I'm with @mark-hahn on this one. The CoffeeScript documentation mentions semicolons pretty early (so this is something many people will have read and assimilated):

First, the basics: CoffeeScript uses significant whitespace to delimit blocks of code. You don't need to use semicolons ; to terminate expressions, ending the line will do just as well (although semicolons can still be used to fit multiple expressions onto a single line).

So, my interpretation from that is that semicolons are optional statement delimiters, that can be used instead of newlines. I see no reason to take them as operators. And i think their rules regarding semicolons on the original CS compiler are pretty consistent:

# Just like you can use newlines to separate statements in a block...
if foo
  bar()
  baz()

# ... you can also use semicolons.
if foo
  bar(); baz()

# And just like you can have more than one newline between statements 
# and the code will mean the same...
if foo
  bar()

  baz()

# ... you can have more than one semicolon.
if foo
  bar();; baz();;;;

So i see no reason to prohibit semicolons at the end of the last statement of a block.

[michaelficarra]

@epidemian: Actually, I think that quote makes my point perfectly. But really, I don't care either way. I could add a special exception that allows trailing semicolons for blocks, and I could change the ; operator to read one or more semicolons. It's not going to be high priority, though. Code like that really disgusts me.

[mehcode]

My perfect code must compile.

bar = (x) ->
  x+=32;;;;;;;;;;;;;;;;;;;;;;;
  ;;;;;;;;;;x+3;;;;;;;;x-=4;;;
  ;;;;;;;;;;;;;;;;;;x==3;;;;;;
  ;;;;;;;;x-51;;;;;;;;;;;;;;;;

In all seriousness I suppose it does make sense to allow the semicolon operator to read one or more semicolons as people are just used to doing that (though I'm not a fan I must say).

---

although semicolons can still be used to fit multiple expressions onto a single line

Just to be clear, redux is doing this. Note that the quote doesn't state the semicolon can be used as the null statement or that empty statements are valid (nor does the document state the latter anywhere).

[michaelficarra]

@mehcode: I couldn't have put it better myself.