For loop should be implemented for strings without declaration

[faze-geek]

Related to #206 which was closed couple of days ago.

a :str
for a in "abc":
      print (a)

(lp) C:\Users\kunni\lpython>python try.py
a
b
c

(lp) C:\Users\kunni\lpython>src\bin\lpython try.py
semantic error: Only function call `range(..)` supported as for loop iteration for now
 --> try.py:3:5 - 4:17
  |
3 |        for a in "abc":
  |        ^^^^^^^^^^^^^^^...
...
  |
4 |            print (a)
  | ...^^^^^^^^^^^^^^^^^

Considering range is the only supported function, a string input is not another function like reverse(str_name) or enumerate(str_name) so a better error message can be provided if this is not in the implementation plan as of now.

[certik]

I think we should implement this. You can change the error message if you want in the meantime.

[faze-geek]

I think we should implement this. You can change the error message if you want in the meantime.

Yes sure! I'll be attempting a few PR's once run_tests starts correctly working with windows. If I'm not wrong #1463 is a shot at that.

[anutosh491]

I've been trying to address this issue , but not sure what approach could be used for the same . Let's say we want to address

i: i32
for i in [1, 2, 3]:
     print(i)

Here the iterable we have is of type AST::List_t and we currently can't address this case but we can address cases where the list has been assigned to a variable .

i: i32
lst: list[i32] = [1, 2, 3]
for i in list:
      print(i)

Here the iterable is of type AST::Name_t . So what comes to my mind for addressing the first case is ... that why don't we assign a dummy name to the list and create an object of AST::Name_t type and repeat the procedure what's being done already . Not sure if this is the way to go here @Thirumalai-Shaktivel !?