On Tue, 3 May 2022 12:07:50 GMT, Jan Lahoda <jlah...@openjdk.org> wrote:
> 8262889: Compiler implementation for Record Patterns > > A first version of a patch that introduces record patterns into javac as a > preview feature. For the specification, please see: > http://cr.openjdk.java.net/~gbierman/jep427+405/jep427+405-20220426/specs/patterns-switch-record-patterns-jls.html > > There are two notable tricky parts: > -in the parser, it was necessary to improve the `analyzePattern` method to > handle nested/record patterns, while still keeping error recovery reasonable > -in the `TransPatterns`, the desugaring of the record patterns is very > straightforward - effectivelly the record patterns are desugared into > guards/conditions. This will likely be improved in some future version/preview > > `MatchException` has been extended to cover additional cases related to > record patterns. I've added some renaming suggestions for the code in Flow, after some discussions with @biboudis. More generally, that code should contain comments, with example of what it's trying to do - e.g. how it's partitioning the set of patterns, etc. src/java.base/share/classes/jdk/internal/javac/PreviewFeature.java line 64: > 62: public enum Feature { > 63: SWITCH_PATTERN_MATCHING, > 64: DECONSTRUCTION_PATTERNS, The spec and JEP talks about record patterns - I think we should follow the correct name here src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java line 751: > 749: Iterable<? extends > JCCaseLabel> labels) { > 750: Set<Symbol> constants = new HashSet<>(); > 751: Map<Symbol, List<JCDeconstructionPattern>> > categorizedDeconstructionPatterns = new HashMap<>(); maybe rename to `deconstructionPatternsBySymbol` ? src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java line 790: > 788: } > 789: > 790: private boolean > coversDeconstructionStartingFromComponent(DiagnosticPosition pos, maybe rename as `coverDeconstructionFromComponent`/`coverDeconstructionAt` src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java line 792: > 790: private boolean > coversDeconstructionStartingFromComponent(DiagnosticPosition pos, > 791: Type > targetType, > 792: > List<JCDeconstructionPattern> patterns, patterns -> "deconstructionPatterns" src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java line 800: > 798: } > 799: > 800: Type parameterizedComponentType = > types.memberType(targetType, components.get(component)); maybe `instantiatedComponentType` src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java line 802: > 800: Type parameterizedComponentType = > types.memberType(targetType, components.get(component)); > 801: List<JCPattern> nestedComponentPatterns = patterns.map(d -> > d.nested.get(component)); > 802: Set<Symbol> nestedCovered = coveredSymbols(pos, > parameterizedComponentType, maybe `coveredComponents` src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java line 807: > 805: Set<Symbol> covered = new HashSet<>(); > 806: > 807: for (JCDeconstructionPattern subTypeCandidate : patterns) { `subTypeCandidate` -> `deconstructionPattern` src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java line 809: > 807: for (JCDeconstructionPattern subTypeCandidate : patterns) { > 808: JCPattern nestedPattern = > subTypeCandidate.nested.get(component); > 809: Symbol currentPatternType; `currentPatternType` -> `componentPatternType` src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java line 823: > 821: } > 822: } > 823: for (Symbol currentType : nestedCovered) { `currentType` -> `coveredComponent` src/jdk.compiler/share/classes/com/sun/tools/javac/tree/JCTree.java line 246: > 244: PARENTHESIZEDPATTERN, > 245: > 246: DECONSTRUCTIONPATTERN, might want to rename to RECORDPATTERN (but this is impl dependent, so less important to fix) src/jdk.compiler/share/classes/com/sun/tools/javac/tree/JCTree.java line 2373: > 2371: } > 2372: > 2373: public static class JCDeconstructionPattern extends JCPattern JCRecordPattern (although this is impl-only, so less important to fix) ------------- PR: https://git.openjdk.java.net/jdk/pull/8516
