Syntax question for CoffeeScript

wat_do.coffee

# Given a function that accepts a function followed by a non-function argument...
foo = (callback, name) ->
  console.log "Calling callback #{name}..."
  callback()

# you end up with a line starting with
# a comma which just feels wrong...
foo ->
  console.log "Callback called!"
, "bar"

# or an awkard set of parens which generates
# unnecessary parens in the compiled source...
foo (->
  console.log "Callback called!"
), "bar"

# or a syntax error.
foo ->
  console.log("Callback called!"), "bar"

# Wat do? What's the preferred way to write this?

Is there a drawback to the extra parens in the generated code? This looks rather nice to me:

q.when createRouteDone,
    ((value) ->
        console.log value),
    (reason) ->
        console.log reason

@irickt

That's great! It turns out the extra parens aren't even needed in that case. This works too:

q.when createRouteDone,
  (value) ->
    console.log value,
  (reason) ->
    console.log reason,
  "non-function parameter"

Without the first argument, it seems you need parens around the whole thing, but it still looks very good to me:

q.when(
  (value) ->
    console.log value,
  (reason) ->
    console.log reason,
  "non-function parameter"
)

/cc @jashkenas, @reshun

@jimmycuadra, in your last version, the commas also aren’t necessary:

q.when(
    (value) ->
        console.log value
    (reason) ->
        console.log reason
    "non-function parameter"
)

I have to admit though that I do find it a bit inconsistent/odd that when arguments are an object (key/value), indentation alone is enough to indicate calling:

somefunc
    foo: '1'
    bar: '2'

but when they’re just positional arguments (whether functions or not), there’s a requirement to either add parentheses, or put one argument and a comma on the same line as the call:

somefunc(
    'yay'
    (spam) -> eggs
)

or:

somefunc 'yay',
    (spam) -> 'eggs'

I’d personally prefer if this was also interpreted as a call instead of a syntax error:

somefunc
    'yay'
    (spam) -> 'eggs'