[Swift-devel] Call function.

[Ben Clifford]

That's moving a big jump away from compile time type checking: you can't check the return types if you don't know anything about the function to call.

Does that matter for Swift? Its nice to find errors before you embark on a long run. But the strongly-typed-ness of swift doesn't otherwise seem too useful.

Do you need general string based invocation? Where are you getting these strings from?

If you want to preserve type checking, then in your example in your message, you could use first order function references (eg: functions in Haskell, function pointers in C) which can carry their type with them.

Your example might then look like:

int assoc_array [ string ] [ int ];
assoc_array[do_x][1] = 1000; assoc_array[do_x][2] = 1001;
assoc_array[do_y][1] = 5000;assoc_array[do_y][2] = 5002;
foreach i in assoc_array {
     foreach vi  in assoc_array[ i ] {
            call ( i , vi  );
}}

All I did there was remove the quotes, and make each function usable as a variable name (which happens in other languages too - both C and Haskell).

The return type of call( f, ...) is then the return type of f, and the type of other parameters of the call are the type the other parameters of f.

That's making the type system more fancy, though, in a way that might not actually make this more useful for users doing actual things. (but I don't know what your real application use case is).

It also excludes the use case of the function names really being dynamic - for example, something like:
s = read(file_containing_a_function_name);
call(s,4);

Is that a use case you expect?