Support new generic function typedef syntax. (#610)

Fix #563.

Author: munificent

CHANGELOG.md

@@ -1,3 +1,7 @@
+# 1.0.2
+
+* Support new generic function typedef syntax (#563).
+
 # 1.0.1
 
 * Ensure space between `-` and `--` (#170).

lib/src/source_visitor.dart

@@ -1181,6 +1181,25 @@ class SourceVisitor extends ThrowingAstVisitor {
     });
   }
 
+  visitGenericFunctionType(GenericFunctionType node) {
+    visit(node.returnType, after: space);
+    token(node.functionKeyword);
+    _visitParameterSignature(node.typeParameters, node.parameters);
+  }
+
+  visitGenericTypeAlias(GenericTypeAlias node) {
+    visitNodes(node.metadata, between: newline, after: newline);
+    _simpleStatement(node, () {
+      token(node.typedefKeyword);
+      space();
+      visit(node.name);
+      space();
+      token(node.equals);
+      space();
+      visit(node.functionType);
+    });
+  }
+
   visitHideCombinator(HideCombinator node) {
     _visitCombinator(node.keyword, node.hiddenNames);
   }
@@ -1555,7 +1574,14 @@ class SourceVisitor extends ThrowingAstVisitor {
       builder.nestExpression();
       modifier(node.covariantKeyword);
       modifier(node.keyword);
-      visit(node.type, after: split);
+
+      visit(node.type);
+
+      // In function declarations and the old typedef syntax, you can have a
+      // parameter name without a type. In the new syntax, you can have a type
+      // without a name. Handle both cases.
+      if (node.type != null && node.identifier != null) split();
+
       visit(node.identifier);
       builder.unnest();
       builder.endRule();
@@ -2016,6 +2042,18 @@ class SourceVisitor extends ThrowingAstVisitor {
       builder.startLazyRule(new Rule(Cost.arrow));
     }
 
+    _visitParameterSignature(typeParameters, parameters);
+
+    if (beforeBody != null) beforeBody();
+    visit(body);
+
+    if (body is ExpressionFunctionBody) builder.unnest();
+  }
+
+  /// Visits the type parameters (if any) and formal parameters of a method
+  /// declaration, function declaration, or generic function type.
+  void _visitParameterSignature(TypeParameterList typeParameters,
+      FormalParameterList parameters) {
     // Start the nesting for the parameters here, so they wrap around the
     // type parameters too, if any.
     builder.nestExpression();
@@ -2026,11 +2064,6 @@ class SourceVisitor extends ThrowingAstVisitor {
     }
 
     builder.unnest();
-
-    if (beforeBody != null) beforeBody();
-    visit(body);
-
-    if (body is ExpressionFunctionBody) builder.unnest();
   }
 
   /// Visits the body statement of a `for`, `for in`, or `while` loop.

pubspec.lock

@@ -6,7 +6,7 @@ packages:
       name: analyzer
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.29.8"
+    version: "0.29.9"
   ansicolor:
     description:
       name: ansicolor

pubspec.yaml

@@ -1,13 +1,13 @@
 name: dart_style
 # Note: See tool/grind.dart for how to bump the version.
-version: 1.0.1
+version: 1.0.2-dev
 author: Dart Team <[email protected]>
 description: Opinionated, automatic Dart source code formatter.
 homepage: https://github.com/dart-lang/dart_style
 environment:
   sdk: ">=1.8.0 <2.0.0"
 dependencies:
-  analyzer: '^0.29.5'
+  analyzer: '^0.29.9'
   args: '>=0.12.1 <0.14.0'
   path: '>=1.0.0 <2.0.0'
   source_span: '>=1.1.1 <2.0.0'

test/splitting/function_types.unit

@@ -0,0 +1,22 @@
+40 columns                              |
+>>> split type parameters (skip: published version of analyzer doesn't support function types yet)
+typedef G = T Function<TypeOne, TypeTwo, TypeThree>();
+<<<
+typedef G = T Function<TypeOne, TypeTwo,
+    TypeThree>();
+>>> split all type parameters (skip: published version of analyzer doesn't support function types yet)
+typedef G = T Function<TypeOne, TypeTwo, TypeThree, TypeFour, TypeFive, TypeSix>();
+<<<
+typedef G = T Function<
+    TypeOne,
+    TypeTwo,
+    TypeThree,
+    TypeFour,
+    TypeFive,
+    TypeSix>();
+>>> split type and value parameters (skip: published version of analyzer doesn't support function types yet)
+typedef G = T Function<TypeOne, TypeTwo, TypeThree>(TypeOne one, TypeTwo two, TypeThree three);
+<<<
+typedef G = T Function<TypeOne, TypeTwo,
+        TypeThree>(TypeOne one,
+    TypeTwo two, TypeThree three);

test/whitespace/function_types.unit

@@ -0,0 +1,28 @@
+40 columns                              |
+>>> non-generic in typedef (skip: published version of analyzer doesn't support function types yet)
+typedef   SomeFunc=ReturnType  Function(int param,   double other);
+<<<
+typedef SomeFunc = ReturnType Function(
+    int param, double other);
+>>> generic in typedef (skip: published version of analyzer doesn't support function types yet)
+typedef Generic = T Function<T>(T param, double other);
+<<<
+typedef Generic = T Function<T>(
+    T param, double other);
+>>> no return type (skip: published version of analyzer doesn't support function types yet)
+typedef SomeFunc = Function();
+<<<
+typedef SomeFunc = Function();
+>>> nested (skip: published version of analyzer doesn't support function types yet)
+typedef SomeFunc = Function(int first, Function(int first, bool second, String third) second, String third);
+<<<
+typedef SomeFunc = Function(
+    int first,
+    Function(int first, bool second,
+            String third)
+        second,
+    String third);
+>>> without param names (skip: published version of analyzer doesn't support function types yet)
+typedef F = Function(int, bool, String);
+<<<
+typedef F = Function(int, bool, String);

test/whitespace/metadata.unit

@@ -253,4 +253,9 @@ function(@Annotation @VeryLongMetadataAnnotation covariant longParameter) {}
 function(
     @Annotation
     @VeryLongMetadataAnnotation
-        covariant longParameter) {}
+        covariant longParameter) {}
+>>> metadata on function typedef (skip: published version of analyzer doesn't support function types yet)
+@foo typedef Fn = Function();
+<<<
+@foo
+typedef Fn = Function();