Collection for

CHANGELOG.md

@@ -1,3 +1,8 @@
+# 1.2.5
+
+* Add support for spreads inside collections (#778).
+* Add support for `if` and `for` elements inside collections (#779).
+
 # 1.2.4
 
 * Update to latest analyzer package AST API.

lib/src/source_visitor.dart

@@ -1159,6 +1159,45 @@ class SourceVisitor extends ThrowingAstVisitor {
     if (nestExpression) builder.unnest();
   }
 
+  void visitForElement(ForElement node) {
+    // Treat a spread of a collection literal like a block in a for statement
+    // and don't split after the for parts.
+    var isSpreadBody = _isSpreadCollection(node.body);
+
+    builder.nestExpression();
+    token(node.awaitKeyword, after: space);
+    token(node.forKeyword);
+    space();
+    token(node.leftParenthesis);
+
+    // Start the body rule so that if the parts split, the body does too.
+    builder.startRule();
+
+    // The rule for the parts.
+    builder.startRule();
+    visit(node.forLoopParts);
+    token(node.rightParenthesis);
+    builder.endRule();
+    builder.unnest();
+
+    builder.nestExpression(indent: 2, now: true);
+
+    if (isSpreadBody) {
+      space();
+    } else {
+      split();
+
+      // If the body is a non-spread collection or lambda, indent it.
+      builder.startBlockArgumentNesting();
+    }
+
+    visit(node.body);
+
+    if (!isSpreadBody) builder.endBlockArgumentNesting();
+    builder.unnest();
+    builder.endRule();
+  }
+
   visitForStatement2(ForStatement2 node) {
     builder.nestExpression();
     token(node.awaitKeyword, after: space);
@@ -1490,23 +1529,6 @@ class SourceVisitor extends ThrowingAstVisitor {
     builder.endRule();
   }
 
-  /// If [node] is a spread of a collection literal, then this returns the
-  /// token for the opening bracket of the collection, as in:
-  ///
-  ///     [ ...[a, list] ]
-  ///     //   ^
-  ///
-  /// Otherwise, returns `null`.
-  Token _findSpreadCollectionBracket(AstNode node) {
-    if (node is SpreadElement) {
-      var expression = node.expression;
-      if (expression is ListLiteral) return expression.leftBracket;
-      if (expression is SetOrMapLiteral) return expression.leftBracket;
-    }
-
-    return null;
-  }
-
   visitIfStatement(IfStatement node) {
     builder.nestExpression();
     token(node.ifKeyword);
@@ -2802,6 +2824,27 @@ class SourceVisitor extends ThrowingAstVisitor {
     builder.endRule();
   }
 
+  /// Whether [node] is a spread of a collection literal.
+  bool _isSpreadCollection(AstNode node) =>
+      _findSpreadCollectionBracket(node) != null;
+
+  /// If [node] is a spread of a collection literal, then this returns the
+  /// token for the opening bracket of the collection, as in:
+  ///
+  ///     [ ...[a, list] ]
+  ///     //   ^
+  ///
+  /// Otherwise, returns `null`.
+  Token _findSpreadCollectionBracket(AstNode node) {
+    if (node is SpreadElement) {
+      var expression = node.expression;
+      if (expression is ListLiteral) return expression.leftBracket;
+      if (expression is SetOrMapLiteral) return expression.leftBracket;
+    }
+
+    return null;
+  }
+
   /// Gets the cost to split at an assignment (or `:` in the case of a named
   /// default value) with the given [rightHandSide].
   ///

pubspec.lock

@@ -7,7 +7,7 @@ packages:
       name: analyzer
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.35.3"
+    version: "0.35.4"
   args:
     dependency: "direct main"
     description:
@@ -21,7 +21,7 @@ packages:
       name: async
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "2.0.8"
+    version: "2.1.0"
   boolean_selector:
     dependency: transitive
     description:
@@ -64,20 +64,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.6"
-  csslib:
-    dependency: transitive
-    description:
-      name: csslib
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.14.6"
   front_end:
     dependency: transitive
     description:
       name: front_end
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.1.13"
+    version: "0.1.14"
   glob:
     dependency: transitive
     description:
@@ -92,13 +85,6 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.8.3"
-  html:
-    dependency: transitive
-    description:
-      name: html
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.13.4+1"
   http:
     dependency: transitive
     description:
@@ -147,14 +133,7 @@ packages:
       name: kernel
       url: "https://pub.dartlang.org"
     source: hosted
-    version: "0.3.13"
-  logging:
-    dependency: transitive
-    description:
-      name: logging
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.11.3+2"
+    version: "0.3.14"
   matcher:
     dependency: transitive
     description:
@@ -218,13 +197,6 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.5.0"
-  plugin:
-    dependency: transitive
-    description:
-      name: plugin
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.2.0+3"
   pool:
     dependency: transitive
     description:
@@ -358,13 +330,6 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.1.6"
-  utf:
-    dependency: transitive
-    description:
-      name: utf
-      url: "https://pub.dartlang.org"
-    source: hosted
-    version: "0.9.0+5"
   vm_service_client:
     dependency: transitive
     description:

pubspec.yaml

@@ -1,6 +1,6 @@
 name: dart_style
 # Note: See tool/grind.dart for how to bump the version.
-version: 1.2.4
+version: 1.2.5-dev
 author: Dart Team <[email protected]>
 description: Opinionated, automatic Dart source code formatter.
 homepage: https://github.com/dart-lang/dart_style

test/splitting/list_collection_for.stmt

@@ -0,0 +1,147 @@
+40 columns                              |
+>>> split collection before for
+var list = [for (a in b) somewhatLongThingHere];
+<<<
+var list = [
+  for (a in b) somewhatLongThingHere
+];
+>>> one line in multi-line
+var list = [veryLongThingThatForcesASplit, for (a in b) 2, 3];
+<<<
+var list = [
+  veryLongThingThatForcesASplit,
+  for (a in b) 2,
+  3
+];
+>>> long body forces split
+var list = [1, for (a in b) veryLongThingThatForcesASplit, 3];
+<<<
+var list = [
+  1,
+  for (a in b)
+    veryLongThingThatForcesASplit,
+  3
+];
+>>> split inside body
+var list = [1, for (a in b) veryLongThingThatForcesASplit + anotherLongThing, 3];
+<<<
+var list = [
+  1,
+  for (a in b)
+    veryLongThingThatForcesASplit +
+        anotherLongThing,
+  3
+];
+>>> trailing comma
+var list = [for (a in b) 2,];
+<<<
+var list = [
+  for (a in b) 2,
+];
+>>> spread list inside for stays on one line if it fits
+var list = [for (a in b) ...[1, 2]];
+<<<
+var list = [
+  for (a in b) ...[1, 2]
+];
+>>> spread list inside for formats like block if it splits
+var list = [for (a in b) ...[1, 2,]];
+<<<
+var list = [
+  for (a in b) ...[
+    1,
+    2,
+  ]
+];
+>>> a split collection that isn't spread wraps and indents
+var list = [for (a in b) [1,2,]];
+<<<
+var list = [
+  for (a in b)
+    [
+      1,
+      2,
+    ]
+];
+>>> lambda inside body
+var list = [for (a in b) () { body; }];
+<<<
+var list = [
+  for (a in b)
+    () {
+      body;
+    }
+];
+>>> nested for doesn't split if it fits
+var l = [for (a in b) for (c in d) t];
+<<<
+var l = [for (a in b) for (c in d) t];
+>>> split collection before nested for
+var list = [for (a in b) for (c in d) longThing];
+<<<
+var list = [
+  for (a in b) for (c in d) longThing
+];
+>>> just split outer for
+var list = [for (a in b) for (c in d) longThingThatIsLong];
+<<<
+var list = [
+  for (a in b)
+    for (c in d) longThingThatIsLong
+];
+>>> split in for-in type
+var list = [for (LongGenericTypeName<TypeArg, AnotherTypeArgument> a in b) body];
+<<<
+var list = [
+  for (LongGenericTypeName<TypeArg,
+      AnotherTypeArgument> a in b)
+    body
+];
+>>> split in for-in expression
+var list = [for (a in sequenceExpression + thatDoesNotFit) body];
+<<<
+var list = [
+  for (a in sequenceExpression +
+      thatDoesNotFit)
+    body
+];
+>>> split in for var type
+var list = [for (LongGenericTypeName<TypeArg, AnotherTypeArgument> a = 0; a < 1; a++) body];
+<<<
+var list = [
+  for (LongGenericTypeName<TypeArg,
+          AnotherTypeArgument> a = 0;
+      a < 1;
+      a++)
+    body
+];
+>>> split in for initializer
+var list = [for (a = initializerExpression + thatDoesNotFit; a < 1; a++) body];
+<<<
+var list = [
+  for (a = initializerExpression +
+          thatDoesNotFit;
+      a < 1;
+      a++)
+    body
+];
+>>> split in for condition
+var list = [for (a = b; conditionExpression + thatDoesNotFit; a++) body];
+<<<
+var list = [
+  for (a = b;
+      conditionExpression +
+          thatDoesNotFit;
+      a++)
+    body
+];
+>>> split in for increment
+var list = [for (a = b; a < 1; incrementExpression + thatDoesNotFit) body];
+<<<
+var list = [
+  for (a = b;
+      a < 1;
+      incrementExpression +
+          thatDoesNotFit)
+    body
+];