Implemented Lshift

[Kishan-Ved]

I thought this would be a good one to get started with LPython implementations.

Reference: https://docs.python.org/3/library/operator.html#operator.lshift

[Kishan-Ved]

@certik Sir the error seems weird. Can we rerun this?

Also, I noticed that many intrinsic functions like Trailz don't have integration tests.

Edit: I have fixed the windows CI error in #2562

[Thirumalai-Shaktivel]

Suggested change

	RUN(NAME intrinsics_03 LABELS llvm) # lshift
	RUN(NAME intrinsics_03 LABELS cpython llvm) # lshift

This verifies that the test works with python as well.

[Kishan-Ved]

Please check the comment below: #2556 (comment)

[Thirumalai-Shaktivel]

Looks good, I have left some comments.

[Thirumalai-Shaktivel]

Please mark this PR ready for review once it is ready.

[Kishan-Ved]

The test fails for cpython, may I please know the reason. The error is:

Traceback (most recent call last): File "/home/kishan/Desktop/lpython/integration_tests/intrinsics_03.py", line 8, in <module> print(lshift(a,b)) NameError: name 'lshift' is not defined 

The file runs when I do ./src/bin/lpython integration_tests/intrinsics_03.py and gives the correct output.

Do I need to make more additions to some files?

[Thirumalai-Shaktivel]

It fails because, python doesn't have builtin lshift support. I think it needs to be imported from the operator module, see: https://docs.python.org/3/library/operator.html#operator.lshift. Something like:

fromoperatorimportlshiftprint(lshift(x, y))

Does x << y work in lpython?

[Kishan-Ved]

It fails because, python doesn't have builtin lshift support. I think it needs to be imported from the operator module, see: https://docs.python.org/3/library/operator.html#operator.lshift. Something like:

fromoperatorimportlshiftprint(lshift(x, y))

Does x << y work in lpython?

Yes, x<<y works in lpython. Also, you are right, lshift() needs to be imported from the operator module and is not built in python.

[Kishan-Ved]

It fails because, python doesn't have builtin lshift support. I think it needs to be imported from the operator module, see: https://docs.python.org/3/library/operator.html#operator.lshift. Something like:

fromoperatorimportlshiftprint(lshift(x, y))

Does x << y work in lpython?

I want lshift to be imported only for the python test. For LPython's implementation, I want the control to be redirected to my intrinsic function. How can I achieve this?
Or should we include the cpython test later, when we implement the operator module for LPython, and there we redirect control to this intrinsic?

[Kishan-Ved]

cc @Thirumalai-Shaktivel@Shaikh-Ubaid