Update constructor syntax (#913)

docs/design/generics/details.md

@@ -224,10 +224,10 @@ class Point {
   impl as Vector {
     // In this scope, "Self" is an alias for "Point".
     fn Add[me: Self](b: Self) -> Self {
-      return Point(.x = a.x + b.x, .y = a.y + b.y);
+      return {.x = a.x + b.x, .y = a.y + b.y};
     }
     fn Scale[me: Self](v: Double) -> Self {
-      return Point(.x = a.x * v, .y = a.y * v);
+      return {.x = a.x * v, .y = a.y * v};
     }
   }
 }
@@ -236,8 +236,8 @@ class Point {
 Interfaces that are implemented inline contribute to the type's API:
 
 ```
-var p1: Point = (.x = 1.0, .y = 2.0);
-var p2: Point = (.x = 2.0, .y = 4.0);
+var p1: Point = {.x = 1.0, .y = 2.0};
+var p2: Point = {.x = 2.0, .y = 4.0};
 Assert(p1.Scale(2.0) == p2);
 Assert(p1.Add(p1) == p2);
 ```
@@ -263,7 +263,7 @@ meaning their data representations are the same, so we allow you to convert
 between the two freely:
 
 ```
-var a: Point = (.x = 1.0, .y = 2.0);
+var a: Point = {.x = 1.0, .y = 2.0};
 // `a` has `Add` and `Scale` methods:
 a.Add(a.Scale(2.0));
 
@@ -376,10 +376,10 @@ class Point2 {
 external impl Point2 as Vector {
   // In this scope, "Self" is an alias for "Point2".
   fn Add[me: Self](b: Self) -> Self {
-    return Point2(.x = a.x + b.x, .y = a.y + b.y);
+    return {.x = a.x + b.x, .y = a.y + b.y};
   }
   fn Scale[me: Self](v: Double) -> Self {
-    return Point2(.x = a.x * v, .y = a.y * v);
+    return {.x = a.x * v, .y = a.y * v};
   }
 }
 ```
@@ -409,7 +409,7 @@ On the other hand, if we convert to the facet type, those methods do become
 visible:
 
 ```
-var a: Point2 = (.x = 1.0, .y = 2.0);
+var a: Point2 = {.x = 1.0, .y = 2.0};
 // `a` does *not* have `Add` and `Scale` methods:
 // ❌ Error: a.Add(a.Scale(2.0));
 
@@ -435,14 +435,14 @@ class Point3 {
   var x: Double;
   var y: Double;
   fn Add[me: Self](b: Self) -> Self {
-    return Point3(.x = a.x + b.x, .y = a.y + b.y);
+    return {.x = a.x + b.x, .y = a.y + b.y};
   }
 }
 
-external Point3 as Vector {
+external impl Point3 as Vector {
   alias Add = Point3.Add;  // Syntax TBD
   fn Scale[me: Self](v: Double) -> Self {
-    return Point3(.x = a.x * v, .y = a.y * v);
+    return {.x = a.x * v, .y = a.y * v};
   }
 }
 ```
@@ -482,8 +482,8 @@ _qualified name_, whether or not the implementation is done externally with an
 `external impl` statement:
 
 ```
-var p1: Point2 = (.x = 1.0, .y = 2.0);
-var p2: Point2 = (.x = 2.0, .y = 4.0);
+var p1: Point2 = {.x = 1.0, .y = 2.0};
+var p2: Point2 = {.x = 2.0, .y = 4.0};
 Assert(p1.(Vector.Scale)(2.0) == p2);
 Assert(p1.(Vector.Add)(p1) == p2);
 ```
@@ -510,7 +510,7 @@ You could access `Draw` with a qualified name:
 import Plot;
 import Points;
 
-var p: Points.Point2 = (.x = 1.0, .y = 2.0);
+var p: Points.Point2 = {.x = 1.0, .y = 2.0};
 p.(Plot.Drawable.Draw)();
 ```
 
@@ -582,8 +582,8 @@ Even though `Point2` doesn't have `Add` and `Scale` methods, it still implements
 `Vector` and so can still call `AddAndScaleGeneric`:
 
 ```
-var a2: Point2 = (.x = 1.0, .y = 2.0);
-var w2: Point2 = (.x = 3.0, .y = 4.0);
+var a2: Point2 = {.x = 1.0, .y = 2.0};
+var w2: Point2 = {.x = 3.0, .y = 4.0};
 var v3: Point2 = AddAndScaleGeneric(a, w, 2.5);
 ```
 
@@ -630,10 +630,10 @@ var VectorForPoint: Vector  = {
     // `lambda` is **placeholder** syntax for defining a
     // function value.
     .Add = lambda(a: Point, b: Point) -> Point {
-      return Point(.x = a.x + b.x, .y = a.y + b.y);
+      return {.x = a.x + b.x, .y = a.y + b.y};
     },
     .Scale = lambda(a: Point, v: Double) -> Point {
-      return Point(.x = a.x * v, .y = a.y * v);
+      return {.x = a.x * v, .y = a.y * v};
     },
 };
 ```
@@ -1518,7 +1518,7 @@ or using qualified names:
 adapter SongByTitle for Song {
   impl as Comparable {
     fn Less[me: Self](that: Self) -> bool {
-      return this.(Song.Title)() < that(Song.Title)();
+      return this.(Song.Title)() < that.(Song.Title)();
     }
   }
 }