Add classical variable support to qasm3_qir_converter

[TheGupta2012]

Fixes #76

Changes

• Added implementation for the classical variable declarations and assignments.
• Elements -
  • scalar type declarations
  • array declarations
  • const declarations
  • scope checking and update
  • scalar assignment
  • array assignment
  • type checking for assignment
  • index validation in assignment
  • array initialization and validation
  • Implicit Type Casting
  • Explicit Type Casting

[ryanhill1]

Thanks for these updates. Gave a couple suggestions for error handling using Exceptions instead of assert. Also consider using collections.deque for the scope dict list. And finally, if you could just add test cases for any new code that would be great.

[TheGupta2012]

Thanks for the suggestions! Was still a WIP so that's why haven't added tests yet. Will update with the changes and tests

[ryanhill1]

Updates look good! The _get_scope method has a bug that will need to be fixed, and offered a couple other optional suggestions for some of the other scope methods.

If you could provide some clarity on the left / right variable constants that you're multiplying that would be helpful.

[ryanhill1]

Looks good to me!

[TheGupta2012]

Yea thanks, had missed this debug statement.
Also, can you hold this PR? I'm yet to write the tests for the exceptions.

[TheGupta2012]

Hey @ryanhill1 , after reviewing you can go ahead and merge. Will take up the last three tasks in another PR as this is getting too big for one feature! I have created a new issue #90 with the leftover stuff