feat: add CtStatement#comment to comment code

[LakshyAAAgrawal]

Add "comment" method to comment out a statement.

In case of a CtBlock, if the parent is a method(the block defines a method body) then the statements within the block are commented out, otherwise, the statement itself is commented out. In case of multiline statements, a block comment is created, otherwise an inline comment is created.

Currently working on testcases for all the child classes of CtStatement.

Fixes #2013

[monperrus]

Thanks for the proposal.

There is a lot of code duplication here.

Here is a tentative solution, by putting adding a single method in CtElementImpl#comment

if (this instanceof CtStatement && getParent() instanceof CtBlock) {
 // do it
} else {
  throw new UnsupportedOperationException()
}

This would make this feature more understandable and maintainable.

WDYT?

[monperrus]

Thanks Benjamin.

[MartinWitt]

Couldn't the instanceOf be replaced with a visitor? Less usage of instanceOf is always better

[monperrus]

that's also an option. but we like to KISS: the simpler the better.

[LakshyAAAgrawal]

Thank you very much for the kind suggestions.

I will make the following changes:

1. Remove CtStatementImpl#comment
2. Add CtElementImpl#comment as described above
3. Keep CtBlock#comment - The implementation for this instance is different from above, since in case of the block being a method body, the inner statements are commented out instead of commenting out the block itself
4. Keep CtStatament#comment - I believe that #comment must be a part of the interface CtStatement but not CtElement.

Kindly let me know about your views on these and I will go ahead with the implementation.

[monperrus]

yes, and remove changes in CtClassImpl, CtUnaryOperatorImpl, CtInvocationImpl, CtConstructorCallImpl, etc.

thanks!

[monperrus]

Thanks a lot!

In Spoon, we have one comment line per test that states the test intention, the contract that is being tested. By convention, it starts with // contract: eg

// contract: a single statement can be commented out

Could you add this contract line in each test?

Thanks!

[LakshyAAAgrawal]

I have added the contract statements.

[monperrus]

Thanks a lot. LGTM, will merge.

[monperrus]

Thanks a lot @LakshyAAAgrawal for your contribution!