Design questions about For-Loops

[cwkr]

I stumbled upon Sparkling because I was searching for a very simple and elegant scripting language. You have designed a very beautiful language, but why is there a For-Loop at all? You have omitted that ugly Switch-Case-Stuff because the same can be done with a chain of Ifs and Elses. As everything that can be done with a For-Loop can also be done with a While-Loop, have you considered replacing the current For-Loop with a Foreach-Loop like construct completely like in Python?

for let i in range(10) {
}
for let i in [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] {
}

…would do exactly the same as…

for let i = 0; i < 10; i++ {
}

…and is even shorter. If it iterates over Arrays (not HashMaps), you could do stuff like:

for let element in ["str", 5, "str"] {
}
for let key in hm.keys() {
    print(hm[key]);
}

It would also make people happy who don’t like the semicolons in the For-loop (#24) and you could use the newly introduces in keyword as some Kind of contains operator:

if "needle" in haystackarray {
}

What do you think?

[H2CO3]

Hi!

You have omitted that ugly Switch-Case-Stuff because the same can be done with a chain
of Ifs and Elses.

Not quite; switch isn't in the language because it was not a primary concern. In fact, it's in my longer-term TODO list, so I plan that Sparkling will eventually have a multi-branch statement or expression.

While we are at it: I'd like to implement proper, functional-style pattern matching, so that might be a bit more involved than a naive transformation from syntactic sugar to an if-ladder. In fact, I don't really like if-ladders, but I haven't yet had the time to design and implement switch.

As everything that can be done with a For-Loop can also be done with a While-Loop,
have you considered replacing the current For-Loop with a Foreach-Loop

Yes, absolutely! In fact, it will probably be the next step in the evolution of the language. A C-style 3-clause for loop seemed like a good idea at first glance back when I was getting started with the design, but really, the usage patterns of Sparkling suggest so far that we'd be far better off having a for…in loop and ditch the C-style construct completely.

Again, implementing that is slightly more complex than a C-style for loop, because the latter effectively desugars to the bytecode of a while loop, whereas a for-in loop would need some sort of special support by the VM and iterable types. But it's definitely planned in the near future, although I can't make a promise when it will be implemented.