How to modify the format of nested structures in SwiftSyntaxBuilder?

Related Projects
1

Howdy!

Disclaimer: I'm playing around with swift-syntax for the first time, so it is very likely I am missing something obvious / doing something wrong. I am using the version from master.

I would like to know if there is a way to modify indentation of nested structures within SwiftSyntaxBuilder. The crux of my issue appears to be with how SwitchCaseList is laid out within a SwitchStmt. In particular, when generating a list of cases, all are placed within a single line like the following (is this even legal syntax?):

switch expr {case .m1: return val case .m2: return val case .m3: return val ... }

It is in contrast with how cases are laid out within a EnumDecl (i.e. line-by-line with appropriate indentation) and which I would expect. e.g. I want it to look like this:

switch expr {
case .m1: 
    return val 
case .m2: 
    return val 
case .m3: 
    return val 
...
}

I am able to get the above form by modifying trivia, but that seems like a hack? It also means I have to hard-code the indentation :frowning:.

Thanks,
smkuehnhold

2

I was able to get the desired format by ham-fistedly making the following changes to the source code (from 6fa8f5e). I am pretty sure it is not a good idea in general to modify "gyb_generated" code by hand, but this is good-enough for me now.

diff --git a/Sources/SwiftSyntaxBuilder/gyb_generated/BuildableCollectionNodes.swift b/Sources/SwiftSyntaxBuilder/gyb_generated/BuildableCollectionNodes.swift
index 9611c0c..04422f1 100644
--- a/Sources/SwiftSyntaxBuilder/gyb_generated/BuildableCollectionNodes.swift
+++ b/Sources/SwiftSyntaxBuilder/gyb_generated/BuildableCollectionNodes.swift
@@ -1315,7 +1315,7 @@ public struct SwitchCaseList: ExpressibleByArrayLiteral, SyntaxBuildable, Expres
 
   public func buildSwitchCaseList(format: Format, leadingTrivia: Trivia? = nil) -> SwitchCaseListSyntax {
     let result = SyntaxFactory.makeSwitchCaseList(elements.map {
-      $0.buildSyntax(format: format, leadingTrivia: nil)
+        $0.buildSyntax(format: format, leadingTrivia: Trivia.newlines(1) + format._makeIndent())
     })
     if let leadingTrivia = leadingTrivia {
       return result.withLeadingTrivia(leadingTrivia + (result.leadingTrivia ?? []))
diff --git a/Sources/SwiftSyntaxBuilder/gyb_generated/BuildableNodes.swift b/Sources/SwiftSyntaxBuilder/gyb_generated/BuildableNodes.swift
index ddbaf30..24c1c14 100644
--- a/Sources/SwiftSyntaxBuilder/gyb_generated/BuildableNodes.swift
+++ b/Sources/SwiftSyntaxBuilder/gyb_generated/BuildableNodes.swift
@@ -9531,7 +9531,7 @@ public struct SwitchStmt: StmtBuildable, ExpressibleAsSwitchStmt {
       expression: expression.buildExpr(format: format, leadingTrivia: nil),
       leftBrace: leftBrace,
       cases: cases.buildSwitchCaseList(format: format, leadingTrivia: nil),
-      rightBrace: rightBrace
+      rightBrace: rightBrace.withLeadingTrivia(.newlines(1) + format._makeIndent() + (rightBrace.leadingTrivia ?? []))
     )
     if let leadingTrivia = leadingTrivia {
       return result.withLeadingTrivia(leadingTrivia + (result.leadingTrivia ?? []))
@@ -10613,12 +10613,19 @@ public struct SwitchCase: SyntaxBuildable, ExpressibleAsSwitchCase {
       statements: statementsBuilder()
     )
   }
-
+//    let result = SyntaxFactory.makeSwitchCaseList(elements.map {
+//        $0.buildSyntax(format: format, leadingTrivia: Trivia.newlines(1) + format._makeIndent())
+//    })
+//    if let leadingTrivia = leadingTrivia {
+//      return result.withLeadingTrivia(leadingTrivia + (result.leadingTrivia ?? []))
+//    } else {
+//      return result
+//    }
   func buildSwitchCase(format: Format, leadingTrivia: Trivia? = nil) -> SwitchCaseSyntax {
     let result = SyntaxFactory.makeSwitchCase(
       unknownAttr: unknownAttr?.buildAttribute(format: format, leadingTrivia: nil),
       label: label.buildSyntax(format: format, leadingTrivia: nil),
-      statements: statements.buildCodeBlockItemList(format: format, leadingTrivia: nil)
+      statements: statements.buildCodeBlockItemList(format: format._indented(), leadingTrivia: nil)
     )
     if let leadingTrivia = leadingTrivia {
       return result.withLeadingTrivia(leadingTrivia + (result.leadingTrivia ?? []))

However this does not really answer my original question unfortunately, so I am still all ears if anyone has a solution to that problem.