auto merge of #9291 : jzelinskie/rust/remove-cond, r=alexcrichton

This is my first contribution, so please point out anything that I may have missed.

I consulted IRC and settled on `match () { ... }` for most of the replacements.

src/libsyntax/ext/expand.rs

@@ -894,42 +894,6 @@ pub fn std_macros() -> @str {
         }
     )
 
-    //
-    // A scheme-style conditional that helps to improve code clarity in some instances when
-    // the `if`, `else if`, and `else` keywords obscure predicates undesirably.
-    //
-    // # Example
-    //
-    // ~~~
-    // let clamped =
-    //     if x > mx { mx }
-    //     else if x < mn { mn }
-    //     else { x };
-    // ~~~
-    //
-    // Using `cond!`, the above could be written as:
-    //
-    // ~~~
-    // let clamped = cond!(
-    //     (x > mx) { mx }
-    //     (x < mn) { mn }
-    //     _        { x  }
-    // );
-    // ~~~
-    //
-    // The optional default case is denoted by `_`.
-    //
-    macro_rules! cond (
-        ( $(($pred:expr) $body:block)+ _ $default:block ) => (
-            $(if $pred $body else)+
-            $default
-        );
-        // for if the default case was ommitted
-        ( $(($pred:expr) $body:block)+ ) => (
-            $(if $pred $body)else+
-        );
-    )
-
     // NOTE(acrichto): start removing this after the next snapshot
     macro_rules! printf (
         ($arg:expr) => (