Replace string_split impl with string_split_noregexp

[cnaples79]

Summary

• Replaces string_split implementation to use SplitNoRegexpProc instead of SplitProc
• Removes the now-obsolete string_split_noregexp function from experimental/string module
• Updates documentation to remove deprecation warnings

Changes Made

fusion/src/fusion/string.fusion

• Changed string_split to use dev.ionfusion.fusion.FusionString$SplitNoRegexpProc
• Removed deprecation warnings from documentation
• Updated docs to clarify that separator is not a regular expression
• Kept reference to regexp_split for users needing regex functionality

fusion/src/fusion/experimental/string.fusion

• Removed string_split_noregexp function entirely (lines 79-96)
• Function is no longer needed since string_split now has the same behavior

Background

The string_split function was accidentally supporting regular expressions, which was unintended and conflicted with the library's design goal of avoiding dependencies on Java language features. The string_split_noregexp function was introduced as a migration path. Now that enough time has passed, we can complete the migration by replacing the implementation.

Fixes #349

[toddjonker]

Hi Chris! Thanks for the contribution.

A couple things need attention:

• We no longer need distinct code paths for regex or not, so we can merge SplitNoRegexpProc into its SplitProc superclass. That also preserves the extant Fusion/Java name alignment convention.
• The test cases in ftst/string.test.fusion have some branching that needs streamlining. I think we should have basically all the current scenarios updated to prove the no-regex behavior.
• The relevant test cases in ftst/experimental/string.test.fusion should also be pulled from that suite into the previous one.
• Be sure to run ./gradlew release to make sure the whole test suite passes. It's also a good idea to look at the generate docs (under build/docs/fusiondoc) to make sure any changes look as expected.

Thanks again! It'll be great to have this fixed at long last.

[toddjonker]

This prose needs updating: the reference to FusionJavaRegexp is vestigial from Amazon. But also we don't need to give migration instructions since there's no current users of this public version of the language. (Any use inside Amazon would necessarily need to use an adaptation layer that would need to advise appropriately.)

The relevant regexp_split code is in this repository on the regexp branch, and the plan is to integrate it into the core. That's what we'd want to reference from here, it just doesn't exist yet.

So we should strip out most of this beyond the semantic clarification.

If you're interested in working on #159 (the regexp integration), please comment on that issue (or reach out on Discord) and ask me to sketch out the approach I have in mind.

[toddjonker]

Did this removal not break test cases?
🤔

[toddjonker]

Oops, it did: https://github.com/ion-fusion/fusion-java/actions/runs/19654525460/job/56291878967?pr=351#step:5:57-60

You can test locally using the check target.

I recommend running ./gradlew clean release on each PR to ensure full build/test success.

[toddjonker]

Also, welcome! I don't think I've seen you around before, and it's great to see the contribution.

Out of curiosity, how did you discover this project?

[toddjonker]

Hi @cnaples79, are you intended to continue this PR? No problem if not, somebody else will pick it up at some point. Still, I'd love to get this through.

If you think the feedback is too onerous to be worth the effort, HMU on Discord and we can seek a middle ground.

Thanks again for your effort!