Merge pull request #94 from DeNA/pretty-dump

Pretty results of dump() for Syntax

Author: Harlan Haskins

Sources/SwiftSyntax/Syntax.swift

@@ -14,7 +14,7 @@
 /// Each node has accessors for its known children, and allows efficient
 /// iteration over the children through its `children` property.
 public protocol Syntax:
-  CustomStringConvertible, TextOutputStreamable {}
+  CustomStringConvertible, CustomDebugStringConvertible, TextOutputStreamable {}
 
 internal protocol _SyntaxBase: Syntax {
   /// The data backing this node.
@@ -275,6 +275,11 @@ extension _SyntaxBase {
     return data.raw.description
   }
 
+  /// Returns a description used by dump.
+  public var debugDescription: String {
+    return String(reflecting: type(of: self))
+  }
+
   /// Prints the raw value of this node to the provided stream.
   /// - Parameter stream: The stream to which to print the raw tree.
   public func write<Target>(to target: inout Target)
@@ -654,6 +659,17 @@ public struct TokenSyntax: _SyntaxBase, Hashable {
   }
 }
 
+extension TokenSyntax: CustomReflectable {
+  public var customMirror: Mirror {
+    return Mirror(self, children: [
+      "text": text,
+      "leadingTrivia": leadingTrivia,
+      "trailingTrivia": trailingTrivia,
+      "tokenKind": tokenKind,
+    ])
+  }
+}
+
 /// Sequence of tokens that are part of the provided Syntax node.
 public struct TokenSequence: Sequence {
   public struct Iterator: IteratorProtocol {
@@ -695,6 +711,12 @@ public struct TokenSequence: Sequence {
   }
 }
 
+extension TokenSequence: CustomReflectable {
+  public var customMirror: Mirror {
+    return Mirror(self, unlabeledChildren: self.map{ $0 })
+  }
+}
+
 /// Reverse sequence of tokens that are part of the provided Syntax node.
 public struct ReversedTokenSequence: Sequence {
   public struct Iterator: IteratorProtocol {
@@ -736,6 +758,12 @@ public struct ReversedTokenSequence: Sequence {
   }
 }
 
+extension ReversedTokenSequence: CustomReflectable {
+  public var customMirror: Mirror {
+    return Mirror(self, unlabeledChildren: self.map{ $0 })
+  }
+}
+
 /// Represents a node from the syntax tree.
 ///
 /// This is a more efficient representation than `Syntax` because it avoids casts

Sources/SwiftSyntax/SyntaxCollections.swift.gyb

@@ -223,6 +223,15 @@ extension ${node.name}: Sequence {
     }
   }
 }
+%   end
+% end
 
+% for node in SYNTAX_NODES:
+%   if node.is_syntax_collection():
+extension ${node.name}: CustomReflectable {
+  public var customMirror: Mirror {
+    return Mirror(self, unlabeledChildren: self.map{ $0 })
+  }
+}
 %   end
 % end

Sources/SwiftSyntax/SyntaxNodes.swift.gyb

@@ -58,6 +58,12 @@ public struct UnknownSyntax: _SyntaxBase, Hashable {
   }
 }
 
+extension UnknownSyntax: CustomReflectable {
+  public var customMirror: Mirror {
+    return Mirror(self, children: [:])
+  }
+}
+
 % for node in SYNTAX_NODES:
 %   base_type = node.base_type
 %   if node.is_base():
@@ -169,7 +175,20 @@ public struct ${node.name}: ${base_type}, _SyntaxBase, Hashable {
     return data.nodeId.hash(into: &hasher)
   }
 }
+%   end
+% end
 
+% for node in SYNTAX_NODES:
+%   if not node.is_base() and not node.is_syntax_collection():
+extension ${node.name}: CustomReflectable {
+  public var customMirror: Mirror {
+    return Mirror(self, children: [
+%     for child in node.children:
+      "${child.swift_name}": ${child.swift_name} as Any,
+%     end
+    ])
+  }
+}
 %   end
 % end
 

Sources/SwiftSyntax/Trivia.swift.gyb

@@ -62,6 +62,13 @@ extension TriviaPiece: TextOutputStreamable {
   }
 }
 
+extension TriviaPiece: CustomDebugStringConvertible {
+  /// Returns a description used by dump.
+  public var debugDescription: String {
+    return "TriviaPiece"
+  }
+}
+
 /// A collection of leading or trailing trivia. This is the main data structure
 /// for thinking about trivia.
 public struct Trivia {

Tests/LinuxMain.swift

@@ -17,6 +17,7 @@ XCTMain({ () -> [XCTestCaseEntry] in
     testCase(TokenSyntaxTestCase.allTests),
     testCase(SyntaxTreeModifierTests.allTests),
     testCase(TriviaTests.allTests),
+    testCase(CustomReflectableTests.allTests),
   ]
   return testCases
 }())