tutorial: Move method discussion after closures, before generics

/cc: rust-lang#4217

Author: brson

doc/tutorial.md

@@ -1480,145 +1480,6 @@ if favorite_crayon_name.len() > 5 {
 }
 ~~~
 
-# Methods
-
-Methods are like functions except that they always begin with a special argument,
-called `self`,
-which has the type of the method's receiver. The
-`self` argument is like `this` in C++ and many other languages.
-Methods are called with dot notation, as in `my_vec.len()`.
-
-_Implementations_, written with the `impl` keyword, can define
-methods on most Rust types, including structs and enums.
-As an example, let's define a `draw` method on our `Shape` enum.
-
-~~~
-# fn draw_circle(p: Point, f: float) { }
-# fn draw_rectangle(p: Point, p: Point) { }
-struct Point {
-    x: float,
-    y: float
-}
-
-enum Shape {
-    Circle(Point, float),
-    Rectangle(Point, Point)
-}
-
-impl Shape {
-    fn draw(&self) {
-        match *self {
-            Circle(p, f) => draw_circle(p, f),
-            Rectangle(p1, p2) => draw_rectangle(p1, p2)
-        }
-    }
-}
-
-let s = Circle(Point { x: 1f, y: 2f }, 3f);
-s.draw();
-~~~
-
-This defines an _implementation_ for `Shape` containing a single
-method, `draw`. In most respects the `draw` method is defined
-like any other function, except for the name `self`.
-
-The type of `self` is the type on which the method is implemented,
-or a pointer thereof. As an argument it is written either `self`,
-`&self`, `@self`, or `~self`.
-A caller must in turn have a compatible pointer type to call the method.
-
-~~~
-# fn draw_circle(p: Point, f: float) { }
-# fn draw_rectangle(p: Point, p: Point) { }
-# struct Point { x: float, y: float }
-# enum Shape {
-#     Circle(Point, float),
-#     Rectangle(Point, Point)
-# }
-impl Shape {
-    fn draw_borrowed(&self) { ... }
-    fn draw_managed(@self) { ... }
-    fn draw_owned(~self) { ... }
-    fn draw_value(self) { ... }
-}
-
-let s = Circle(Point { x: 1f, y: 2f }, 3f);
-
-(@s).draw_managed();
-(~s).draw_owned();
-(&s).draw_borrowed();
-s.draw_value();
-~~~
-
-Methods typically take a borrowed pointer self type,
-so the compiler will go to great lengths to convert a callee
-to a borrowed pointer.
-
-~~~
-# fn draw_circle(p: Point, f: float) { }
-# fn draw_rectangle(p: Point, p: Point) { }
-# struct Point { x: float, y: float }
-# enum Shape {
-#     Circle(Point, float),
-#     Rectangle(Point, Point)
-# }
-# impl Shape {
-#    fn draw_borrowed(&self) { ... }
-#    fn draw_managed(@self) { ... }
-#    fn draw_owned(~self) { ... }
-#    fn draw_value(self) { ... }
-# }
-# let s = Circle(Point { x: 1f, y: 2f }, 3f);
-// As with typical function arguments, managed and unique pointers
-// are automatically converted to borrowed pointers
-
-(@s).draw_borrowed();
-(~s).draw_borrowed();
-
-// Unlike typical function arguments, the self value will
-// automatically be referenced ...
-s.draw_borrowed();
-
-// ... and dereferenced
-(& &s).draw_borrowed();
-
-// ... and dereferenced, and borrowed, and
-(&@~s).draw_borrowed();
-~~~
-
-Implementations may also define _static_ methods,
-which don't have an explicit `self` argument.
-The `static` keyword distinguishes static methods from methods that have a `self`:
-
-~~~~ {.xfail-test}
-impl Circle {
-    fn area(&self) -> float { ... }
-    static fn new(area: float) -> Circle { ... }
-}
-~~~~
-
-> ***Note***: In the future the `static` keyword will be removed and static methods
-> will be distinguished solely by the presence or absence of the `self` argument.
-> In the current langugage instance methods may also be declared without an explicit
-> `self` argument, in which case `self` is an implicit reference.
-> That form of method is deprecated.
-
-Constructors are one common application for static methods, as in `new` above.
-To call a static method, you have to prefix it with the type name and a double colon:
-
-~~~~
-# use float::consts::pi;
-# use float::sqrt;
-struct Circle { radius: float }
-impl Circle {
-    static fn new(area: float) -> Circle { Circle { radius: sqrt(area / pi) } }
-}
-let c = Circle::new(42.5);
-~~~~
-
-We'll discuss implementations more in the context of [traits and
-generics](#generics).
-
 # Closures
 
 Named functions, like those we've seen so far, may not refer to local
@@ -1886,6 +1747,142 @@ fn contains(v: &[int], elt: int) -> bool {
 > the keywords `break`, `loop`, and `return` work, in varying degree,
 > with `while`, `loop`, `do`, and `for` constructs.
 
+# Methods
+
+Methods are like functions except that they always begin with a special argument,
+called `self`,
+which has the type of the method's receiver. The
+`self` argument is like `this` in C++ and many other languages.
+Methods are called with dot notation, as in `my_vec.len()`.
+
+_Implementations_, written with the `impl` keyword, can define
+methods on most Rust types, including structs and enums.
+As an example, let's define a `draw` method on our `Shape` enum.
+
+~~~
+# fn draw_circle(p: Point, f: float) { }
+# fn draw_rectangle(p: Point, p: Point) { }
+struct Point {
+    x: float,
+    y: float
+}
+
+enum Shape {
+    Circle(Point, float),
+    Rectangle(Point, Point)
+}
+
+impl Shape {
+    fn draw(&self) {
+        match *self {
+            Circle(p, f) => draw_circle(p, f),
+            Rectangle(p1, p2) => draw_rectangle(p1, p2)
+        }
+    }
+}
+
+let s = Circle(Point { x: 1f, y: 2f }, 3f);
+s.draw();
+~~~
+
+This defines an _implementation_ for `Shape` containing a single
+method, `draw`. In most respects the `draw` method is defined
+like any other function, except for the name `self`.
+
+The type of `self` is the type on which the method is implemented,
+or a pointer thereof. As an argument it is written either `self`,
+`&self`, `@self`, or `~self`.
+A caller must in turn have a compatible pointer type to call the method.
+
+~~~
+# fn draw_circle(p: Point, f: float) { }
+# fn draw_rectangle(p: Point, p: Point) { }
+# struct Point { x: float, y: float }
+# enum Shape {
+#     Circle(Point, float),
+#     Rectangle(Point, Point)
+# }
+impl Shape {
+    fn draw_borrowed(&self) { ... }
+    fn draw_managed(@self) { ... }
+    fn draw_owned(~self) { ... }
+    fn draw_value(self) { ... }
+}
+
+let s = Circle(Point { x: 1f, y: 2f }, 3f);
+
+(@s).draw_managed();
+(~s).draw_owned();
+(&s).draw_borrowed();
+s.draw_value();
+~~~
+
+Methods typically take a borrowed pointer self type,
+so the compiler will go to great lengths to convert a callee
+to a borrowed pointer.
+
+~~~
+# fn draw_circle(p: Point, f: float) { }
+# fn draw_rectangle(p: Point, p: Point) { }
+# struct Point { x: float, y: float }
+# enum Shape {
+#     Circle(Point, float),
+#     Rectangle(Point, Point)
+# }
+# impl Shape {
+#    fn draw_borrowed(&self) { ... }
+#    fn draw_managed(@self) { ... }
+#    fn draw_owned(~self) { ... }
+#    fn draw_value(self) { ... }
+# }
+# let s = Circle(Point { x: 1f, y: 2f }, 3f);
+// As with typical function arguments, managed and unique pointers
+// are automatically converted to borrowed pointers
+
+(@s).draw_borrowed();
+(~s).draw_borrowed();
+
+// Unlike typical function arguments, the self value will
+// automatically be referenced ...
+s.draw_borrowed();
+
+// ... and dereferenced
+(& &s).draw_borrowed();
+
+// ... and dereferenced, and borrowed, and
+(&@~s).draw_borrowed();
+~~~
+
+Implementations may also define _static_ methods,
+which don't have an explicit `self` argument.
+The `static` keyword distinguishes static methods from methods that have a `self`:
+
+~~~~ {.xfail-test}
+impl Circle {
+    fn area(&self) -> float { ... }
+    static fn new(area: float) -> Circle { ... }
+}
+~~~~
+
+> ***Note***: In the future the `static` keyword will be removed and static methods
+> will be distinguished solely by the presence or absence of the `self` argument.
+> In the current langugage instance methods may also be declared without an explicit
+> `self` argument, in which case `self` is an implicit reference.
+> That form of method is deprecated.
+
+Constructors are one common application for static methods, as in `new` above.
+To call a static method, you have to prefix it with the type name and a double colon:
+
+~~~~
+# use float::consts::pi;
+# use float::sqrt;
+struct Circle { radius: float }
+impl Circle {
+    static fn new(area: float) -> Circle { Circle { radius: sqrt(area / pi) } }
+}
+let c = Circle::new(42.5);
+~~~~
+
 # Generics
 
 Throughout this tutorial, we've been defining functions that act only