Add CompareAndSwap and Swap to String, Error, Value, Deprecate CAS

[eNV25]

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From #108 .

Add CompareAndSwap and Swap for String and Error. Deprecate CAS.

This is not done for Time since it is not meant to be compared.

I also have a commit bcb50e9, that deprecates CAS and adds CompareAndSwap to align with sync/atomic from go1.19. Since that commit depends on this one, I can only open a PR after this is merged.

[codecov]

Codecov Report

Merging #111 (d2c8de7) into master (d15bdad) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master      #111   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           20        20           
  Lines          201       215   +14     
=========================================
+ Hits           201       215   +14     

Impacted Files	Coverage Δ
error_ext.go	100.00% <ø> (ø)
string_ext.go	100.00% <ø> (ø)
bool.go	100.00% <100.00%> (ø)
duration.go	100.00% <100.00%> (ø)
error.go	100.00% <100.00%> (ø)
float32_ext.go	100.00% <100.00%> (ø)
float64_ext.go	100.00% <100.00%> (ø)
int32.go	100.00% <100.00%> (ø)
int64.go	100.00% <100.00%> (ø)
string.go	100.00% <100.00%> (ø)
... and 4 more

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[abhinav]

The change largely looks good minus minor comments.

However, I'm concerned about introducing CAS methods for String, Error, and Value and at the same time deprecating them in favor of CompareAndSwap.

Could we possibly skip that step? No CAS methods for things that didn't already have one?

[eNV25]

However, I'm concerned about introducing CAS methods for String, Error, and Value and at the same time deprecating them in favor of CompareAndSwap.

I guess that means merging the commits, then removing the new CAS methods.

[eNV25]

then removing the new CAS methods.

I could do this by introducing a -compareandswap flag to the generator. The existing -cas flag would imply -compareandswap.

This is the only way to do this cleanly, I think. @abhinav What do you think?

Until feedback, I'll just update the PR to add the other commit that deprecates CAS. I can then implement the above later, after squashing all these commits.

[abhinav]

I could do this by introducing a -compareandswap flag to the generator. The existing -cas flag would imply -compareandswap.

This is the only way to do this cleanly, I think. @abhinav What do you think?

That sounds reasonable. The code generator is private so we can change its flags however we want.
-cas implies -compareandswap makes sense to me.

Thanks!

[abhinav]

Thanks for making all the changes!

[abhinav]

Thanks!