Forloops/iterator Milestone 2

[tapan0007]

Note (before merging): We had to merge other group branches (sets, strings, destructuring, generics) to support iterators on these.

We have implemented the following for Milestone 2:

1. Iterators for lists, strings, and sets.
2. iter() and next() function for any iterable object - custom and inbuilt iterator.
3. StopIteration error after iterable is exhausted.
4. Enumerate() for lists of int (can be supported only for lists of int as these structures are not supported yet: [1, False], [1, [1]]).
5. For loops on generic iterators.
6. Destructuring in for loop head, (eg: for I,j in iterable). The iterable has to be a list type.

Please check our test cases for more information on these functionalities.

[simranbarnwal]

Note (before merging): We had to merge other group branches (sets, strings, destructuring, generics) to support iterators on these.

We have implemented the following for Milestone 2:

1. Iterators for lists, strings, and sets.
2. iter() and next() function for any iterable object - custom and inbuilt iterator.
3. StopIteration error after iterable is exhausted.
4. Enumerate() for lists of int (can be supported only for lists of int as these structures are not supported yet: [1, False], [1, [1]]).
5. For loops on generic iterators.
6. Destructuring in for loop head, (eg: for I,j in iterable). The iterable has to be a list type.

Please check our test cases for more information on these functionalities.

Three tests aren't working currently: generics: two typevars (due to interaction with strings), sets (update-list, firstitem() due to memory error)