Threat throw same as function.

[al6x]

Throw in CS threat somehow similar to function, but this

(@onError|throw) new Error(msg)

doesn't compile, while

(@onError|@somethingOther) new Error(msg)

does.

[vendethiel]

because throw is a statement, not an expression (like return)

[michaelficarra]

To elaborate, throw, return, continue, and break are the only statements that CoffeeScript refuses to treat as expressions because they affect control flow.

[epidemian]

There seems to be a difference between throw and the others though. throw <expr> can be used as an expression while return|continue|break <expr> can't:

# Both lines compile.
foo throw bar, 42
baz or throw qux

# Neither of these lines compile.
foo return bar, 42
baz or return qux

Given that that difference exists, couldn't we compile:

(@onError or throw) new Error msg

to:

(this.onError || function(e) {
  throw e;
})(new Error(msg));

?

And, would it make sense to do so?

[vendethiel]

Then people will ask us to support (monoid or (+)).
We could compile it to a throwing function, knowing we're gonna add a line in the stack trace (and checking we're correctly carrying arguments)

[michaelficarra]

@epidemian: I actually didn't know about that. I'm going to have to add that to CoffeeScriptRedux.

[al6x]

Yes, right now throw is like a half expression, would be nice to make it as a plain expression.