That's a whole different matter, which can't make you shoot yourself in the foot without knowing it for any non-trivial code.
CoffeeScript's scoping forces you to always keep track of whatever is enclosing the current scope ALL THE WAY TO THE TOP. This is way too much when your function doesn't need to access outer variables (which should be the minority of the cases).
So, problem is, you either make all your functions have non-free variables (but Jashkenas seems to dislike functions shadowing outer variables too, which is just... overtly weird), or you keep track of all variables above the current scope.
The former is not too unreasonable, until you remember it makes no sense with closures :3
Never said it was an object literal eh. Object literals can only occur inside expressions, that's pretty well defined in the JavaScript AST too, which is described to the utmost detail in the ECMAScript specs.
The thing is:
- `return` alone is a valid statement in its own.
- The parser just need to use a simple lookahead to decide whether the next line is part of the previous statement.
- The parser DON'T change the meaning of your programs.
All that's beside that is a matter of taste. Whether use semicolons or not is up to what sits better with each person. I'm just arguing against the silly and incorrect "technical" arguments against it.
I really don't see any problem with the way JavaScript handles it. "Unless the following line can be part of the preceding statement, end the current statement" is a pretty natural thing to me. But well, I guess that's a matter of taste, and you can't really discuss that...
That's not a problem with the line joining stuff. Both `return' and `{ foo: bar }' are ENTIRE VALID statements in their own right.
returnStmt ::= "return" [ expression ] (";" or EOL)
Note that expression is optional, so it's the choice of `return' by itself being a valid statement on its own that "causes problems".
Plus, this is not really a problem that can be solved by simply putting semicolons everywhere. You can't change the parser rules by including or not semicolons.
Also, same thing with break/continue:
breakStmt ::= "break" [ label ] (";" or EOL)
continueStmt ::= "continue" [ label ] (";" or EOL)
And where would JavaScript not handle them in a way people don't expect them to be handled?
Comparing Python's handling of semicolons with JavaScript's ASI, you get the following:
-- End of statements
Python and JavaScript: Ends with either a new line or a semicolon.
-- Line joining
Python: whitespace strict, so lines must be either explicitly joined through the `\' escape character, or put inside a parenthesized expression, which ignores whitespace.
JavaScript: non-whitespace strict, so lines don't need to be explicitly joined. Statements may be continued by starting the following line with a continuation token (one of: `[ ( + - /')
-- Exceptions
Python: Parenthesized expressions use a different parser state (ie.: whitespace strict vs non-whitespace strict)
JavaScript: restricted production grammar usually have optional expressions following them, and since they are a valid statement on their own, the statement will be ended with a new line. So, the related information must start in the same line.
Restricted productions are: return, break and continue; Post-fix and prefix operators are included as restricted productions for readability's sake.
I fail to see how that's difficult to remember, or how that's insanely more complex than Python's rules...
CoffeeScript's scoping forces you to always keep track of whatever is enclosing the current scope ALL THE WAY TO THE TOP. This is way too much when your function doesn't need to access outer variables (which should be the minority of the cases).
So, problem is, you either make all your functions have non-free variables (but Jashkenas seems to dislike functions shadowing outer variables too, which is just... overtly weird), or you keep track of all variables above the current scope.
The former is not too unreasonable, until you remember it makes no sense with closures :3