Refactor docCommentTrivia() to Trivia extension

Author: natikgadzhi

CodeGeneration/Sources/SyntaxSupport/Child.swift

@@ -106,7 +106,7 @@ public class Child {
         \(choices.map { " - \(grammar.grammar(for: $0))" }.joined(separator: "\n"))
         """
 
-      let tokenChoicesTrivia = docCommentTrivia(
+      let tokenChoicesTrivia = SwiftSyntax.Trivia.docCommentTrivia(
         from: """
           ### Tokens
 
@@ -258,7 +258,7 @@ public class Child {
     self.deprecatedName = deprecatedName
     self.kind = kind
     self.nameForDiagnostics = nameForDiagnostics
-    self.documentationSummary = docCommentTrivia(from: documentation)
+    self.documentationSummary = SwiftSyntax.Trivia.docCommentTrivia(from: documentation)
     self.documentationAbstract = String(documentation?.split(whereSeparator: \.isNewline).first ?? "")
     self.isOptional = isOptional
   }

CodeGeneration/Sources/SyntaxSupport/Node.swift

@@ -121,7 +121,7 @@ public class Node {
     self.base = base
     self.isExperimental = isExperimental
     self.nameForDiagnostics = nameForDiagnostics
-    self.documentation = docCommentTrivia(from: documentation)
+    self.documentation = SwiftSyntax.Trivia.docCommentTrivia(from: documentation)
     self.parserFunction = parserFunction
 
     let childrenWithUnexpected: [Child]
@@ -211,7 +211,7 @@ public class Node {
       }
       .joined(separator: "\n")
 
-    return docCommentTrivia(
+    return .docCommentTrivia(
       from: """
         ### Contained in
 
@@ -237,7 +237,7 @@ public class Node {
     self.base = base
     self.isExperimental = isExperimental
     self.nameForDiagnostics = nameForDiagnostics
-    self.documentation = docCommentTrivia(from: documentation)
+    self.documentation = SwiftSyntax.Trivia.docCommentTrivia(from: documentation)
     self.parserFunction = parserFunction
 
     assert(!elementChoices.isEmpty)
@@ -299,7 +299,7 @@ public struct LayoutNode {
       return []
     }
 
-    return docCommentTrivia(
+    return .docCommentTrivia(
       from: """
         ### Children
 
@@ -352,7 +352,7 @@ public struct CollectionNode {
       grammar = "(\(elementChoices.map { "``\($0.syntaxType)``" }.joined(separator: " | "))) `*`"
     }
 
-    return docCommentTrivia(
+    return .docCommentTrivia(
       from: """
         ### Children
 

CodeGeneration/Sources/SyntaxSupport/Traits.swift

@@ -21,7 +21,7 @@ public class Trait {
   init(traitName: String, documentation: String? = nil, children: [Child]) {
     self.traitName = traitName
     self.protocolName = .identifier("\(traitName)Syntax")
-    self.documentation = docCommentTrivia(from: documentation)
+    self.documentation = SwiftSyntax.Trivia.docCommentTrivia(from: documentation)
     self.children = children
   }
 }

CodeGeneration/Sources/SyntaxSupport/Utils.swift

@@ -38,21 +38,39 @@ public func lowercaseFirstWord(name: String) -> String {
   return name.prefix(wordIndex).lowercased() + name[name.index(name.startIndex, offsetBy: wordIndex)..<name.endIndex]
 }
 
-/// Give a (possibly multi-line) string, prepends `///` to each line and creates
-/// a `.docLineComment` trivia piece for each line.
-public func docCommentTrivia(from string: String?) -> SwiftSyntax.Trivia {
-  guard let string else {
-    return []
-  }
-  let lines = string.split(separator: "\n", omittingEmptySubsequences: false)
-  let pieces = lines.enumerated().map { (index, line) in
-    var line = line
-    if index != lines.count - 1 {
-      line = "\(line)\n"
+// Helpers to create trivia pieces
+extension SwiftSyntax.Trivia {
+  /// Make a new trivia from a (possibly multi-line) string, prepending `///`
+  /// to each line and creating a `.docLineComment` trivia piece for each line.
+  public static func docCommentTrivia(from string: String?) -> SwiftSyntax.Trivia {
+    guard let string else {
+      return []
+    }
+
+    let lines = string.split(separator: "\n", omittingEmptySubsequences: false)
+    let pieces = lines.enumerated().map { (index, line) in
+      var line = line
+      if index != lines.count - 1 {
+        line = "\(line)\n"
+      }
+      return SwiftSyntax.TriviaPiece.docLineComment("/// \(line)")
     }
-    return SwiftSyntax.TriviaPiece.docLineComment("/// \(line)")
+    return SwiftSyntax.Trivia(pieces: pieces)
+  }
+
+
+  /// Make a new trivia by joining together ``SwiftSyntax/TriviaPiece``s from `joining`,
+  /// and gluing them together with pieces from `separator`.
+  public init(
+    joining items: [SwiftSyntax.Trivia],
+    separator: SwiftSyntax.Trivia = SwiftSyntax.Trivia(pieces: [TriviaPiece.newlines(1), TriviaPiece.docLineComment("///"), TriviaPiece.newlines(1)])) {
+
+    self.init(
+      pieces: items
+        .filter { !$0.isEmpty }
+        .joined(separator: separator)
+    )
   }
-  return SwiftSyntax.Trivia(pieces: pieces)
 }
 
 public extension Collection {

CodeGeneration/Sources/generate-swift-syntax/LayoutNode+Extensions.swift

@@ -92,7 +92,7 @@ extension LayoutNode {
       If the node is empty, there is no token to attach the trivia to and the parameter is ignored.
       """.removingEmptyLines
 
-    return docCommentTrivia(from: formattedParams)
+    return SwiftSyntax.Trivia.docCommentTrivia(from: formattedParams)
   }
 
   /// Create a builder-based convenience initializer, if needed.