Define Syntax for Iterator Definition

[kindlich]

Currently, StdLib's Iterable.zs defines the Iterator-Member like so:

for(item as T) as Iterator<T> => iterate();

However, the parser expects:

for(T) {
    // What to do in here?
}

Defined in ParsedDefinitionMember:

            case K_FOR: {
                tokens.next();

                tokens.required(T_BROPEN, "( expected");

                List<IParsedType> loopVariableTypes = new ArrayList<>();
                if (tokens.optional(T_BRCLOSE) == null) {
                    do {
                        loopVariableTypes.add(IParsedType.parse(tokens));
                    } while (tokens.optional(T_COMMA) != null);
                    tokens.required(T_BRCLOSE, ") expected");
                }

                ParsedFunctionBody body = ParsedStatement.parseFunctionBody(tokens);
                return new ParsedIterator(start, modifiers, annotations, loopVariableTypes, body);
            }

We need to define how the iterator members should look like and how it should behave.

Acceptance Criteria:

• [ ] The syntax is defined
• [ ] The header in stdlibs is adapted to whatever syntax we adopt
• [ ] There exist tests that cover the basic iterator functionality
  • [ ] Defining an iterator
  • [ ] Calling it
  • [ ] Overloading iterators with multiple variables
  • [ ] Doing that on a generic data type like List