AssemblyScript
break: Add support for labeled statements, breaks, and continues
Fixes #2889.
Changes proposed in this pull request:
⯈ Support labeled statements in the parser/AST
⯈ Support labeled break/continue.
This change is breaking solely because it modifies the Node.createXXX APIs, which are used by transforms.
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I just need to add some tests; then, this will be ready to merge.
@JairusSW Heads up: this change definitely breaks transforms. Do you have anything to comment on this PR?
Okay, it appears that my code breaks something related to Flow flags, so more work on this PR is needed.
One issue is that breaking out of a labeled block sets the Breaks flag on the outer flow and messes with the function not appearing to always terminate.
Another issue is that a continue (and likely break as well) from inside an inner loop to an outer loop won't set the Continues/ConditionallyContinues flow flag on the outer loop body's flow. This is a much more significant issue (since nested loops are the most common use of labels) and seems to be more difficult to fix...
In TS, there are new ASTNode LabeledStatement to identifier this labeled statement, could we use the same concept?
@HerrCai0907 I considered that before, and it might be a pretty good idea. It would be better for transform users for sure.
Still, there's the issue of setting the proper FlowFlags for a continue to an outer loop...maybe the class I use to keep track of labels should contain the flow, and I can use something like do flow.set(...) while ((flow = flow.parent) != targetFlow). (Of course, the actual code would look nicer than that.)