[Parser] Simplify sequence expression parsing #628
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DougGregor
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Aug 23, 2022
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This is fantastic, and a huge help for the operator-precedence library in #619.
| @@ -42,23 +42,6 @@ extension Parser { | |||
| } | |||
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| extension Parser { | |||
| struct PendingTernary { | |||
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I'm so glad to see this struct go away. The parser is much simpler now!
| /// type-casting-operator → 'is' type | ||
| /// type-casting-operator → 'as' type | ||
| /// type-casting-operator → 'as' '?' type | ||
| /// type-casting-operator → 'as' '!' type |
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Do we need to document the arrow operator here?
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`SequenceExprSyntax` now gurantees that it has odd number elements using `UnresolvedTernaryExpr`/`UnresolvedAsExpr`/`UnresolvedIsExpr`. Factored out the operator parsing into `parseSequenceExpressionOperator()` which returns the operator expresssion, and optionally the RHS, so we can avoid nested loops. Also, `parseSequenceExprssion()` now has a performance optimization that avoids heap `Array` construction unless the expression is actually sequenced.
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swiftlang/swift#60731 |
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(Depends on swiftlang/swift#60731)
SequenceExprSyntaxnow gurantees that it has odd number elements usingUnresolvedTernaryExpr/UnresolvedAsExpr/UnresolvedIsExpr.Factored out the operator parsing into
parseSequenceExpressionOperator()which returns the operator expresssion, and optionally the RHS, so we can avoid nested loops.Also,
parseSequenceExprssion()now has a performance optimization that avoids heapArrayconstruction unless the expression is actually sequenced.