swiftlang/swift

Fill out unimplemented expression cases in the ASTPrinter

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#61,601 opened on Oct 17, 2022

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ASTPrintercompilerexpressionsgood first issue

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Description

In #40691 we added initial support for printing Expr nodes in the ASTPrinter, and #64667 filled out most of the rest. However there are still some expressions left unimplemented, including:

  • All the ImplicitConversionExpr subclasses, we should stamp out their definitions as printing their sub-expression, using a macro
  • InterpolatedStringLiteralExpr (this is a tricky case since we'd need to reconstruct the string literal from the TapExpr, or otherwise preserve its original form)

These are partially implemented, with outstanding FIXMEs:

  • ClosureExpr
  • CaptureListExpr
  • KeyPathExpr

Some extras tests would be good for:

  • SubscriptExpr (would be great to have a test exercising some other call patterns, e.g multiple arguments, argument labels)
  • TupleElementExpr
  • ObjCSelectorExpr
  • DynamicSubscriptExpr
  • EnumIsCaseExpr
  • MakeTemporarilyEscapableExpr
  • EditorPlaceholderExpr
  • DotSyntaxBaseIgnoredExpr

Contributor guide

Research direction
Study the existing ASTPrinter implementation, particularly the Expr printer in Swift compiler. Look at how other expression types are printed (e.g., in #40691 and #64667). For ImplicitConversionExpr subclasses, understand the macro pattern. For InterpolatedStringLiteralExpr, research how TapExpr is used. Then implement the missing cases and add tests.
Tech stack
swiftcpp
Domain
toolingdeveloper experience
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Over 1 week
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
SwiftC++GitCompiler Development
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50