Refactoring the Qasm3Visitor

[TheGupta2012]

Fixes #136

Summary of changes

• With the addition of new constructs in the visitor, a refactoring was needed for the module
• Validators, helpers and some other methods were factored out of the Qasm3Visitor. These were independent of the self and moved out to a separate utility class. Moreover, it made sense to keep all the _visit_* methods in the visitor.
• Imports for openqasm3 were also moved to a different file
• One possible separation could also be done based on the constructs i.e. GateUtils, VariableUtils, etc. but felt a bit of an overkill

@ryanhill1 would like to hear your thoughts on this too, thanks!

[codecov]

Codecov Report

Attention: Patch coverage is 97.44409% with 8 lines in your changes missing coverage. Please review.

Files	Patch %	Lines
qbraid_qir/qasm3/expressions.py	95.23%	4 Missing ⚠️
qbraid_qir/qasm3/validator.py	97.91%	2 Missing ⚠️
qbraid_qir/qasm3/exceptions.py	88.88%	1 Missing ⚠️
qbraid_qir/qasm3/transformer.py	98.38%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[ryanhill1]

1. Let's remove the qasm3.utils.imports file and instead use namespace imports in qasm3.visitor and other files that have big import blocks.
2. Please refactor to eliminate any ascending relative imports. This can be done either by moving all of files within qasm3.utils up to the qasm3 module level, or potentially with some clever inversion of the module structure. In the former, there would still only be 8 python files within the top-level qasm3 module, which isn't that bad.

See comments below.

[ryanhill1]

Overall looking much better! Last few things to address which I mention in more detail below:

• Making sure all functions have appropriate type hints (this will also help make Add static type checking with mypy #145 easier)
• Combine in the print_err_location and exception raising by either modifying the existing Qasm3ConversionError exception class or creating a helper function that both raises the exception and logs/prints the element line/column traceback.
• Rename the visitor_utils file and Qasm3VisitorUtils class to something a bit more descriptive. Regroup validators / analyzers / transformers as necessary.

[ryanhill1]

Please add type hints to all methods to comply with py.typed

[TheGupta2012]

• Hi @ryanhill1 , segregated the validator, transformer and analyser into respective files.
• Made a separate error function.
• Also changed the structure of these classes to include an attribute which refers to the BasicQasmVisitor object. This will remove the dependency of the visitor from the function calls. Methods referring to the object are now classmethods and reference this object internally.

[ryanhill1]

These updates look great! If you could just address the two lines of unreachable code I noted below either by updating the typehint, or removing them. After that it should be good

Edit: Also, is the supported conversions table up to date? And if not, could you update it? Thanks!

[TheGupta2012]

Sure, will change. Also, some type hints are still left but I'll address them in the mypy issue