Function arguments provided from an array or iterator.

[otrho]

At the moment the FunctionBuilder only allows args to be added via with_arg(). In the io::Assembler::parse_fn() it's using a for-loop to pump args in one at a time, which feels a bit clumsy. Adding a .with_args() would be good IMO, taking a slice of pairs, or even an iterator.

I've also used the following to fold the builder, which felt more functional than a for-loop, but is still fairly inelegant:

    let func = args
        .iter()
        .fold(
            module
                .create_function(context)
                .with_attributes(attrs)
                .with_name(name)
                .with_return_type(ret_type),
            |bldr, &arg: &(&str, Type)| bldr.with_arg(arg.0, arg.1),
        )
        .build();

[sheredom]

Adding a with_args would be fine yeah, nothing against that!