removed guard as it matches cond almost exactly, added case

docs/contrib/flow.rst

@@ -2,7 +2,7 @@
 Flow
 ==========
 
-.. versionadded:: 0.10.2
+.. versionadded:: 0.10.1
 
 The ``flow`` macros allow a programmer to direct the flow of his program with
 greater ease.
@@ -11,16 +11,16 @@ greater ease.
 Macros
 ======
 
-.. _guard:
+.. _case:
 .. _switch:
 
-guard
+case
 -----
 
-``guard`` allows you to guard against a condition.
+``case`` allows you to decide based on the value of a variable.
 
 
-Usage: `(guard (cond1) (body1) (cond2) (body2) ...)`
+Usage: `(case variable val1 (body1) val2 (body2) ...)`
 
 Example:
 
@@ -28,11 +28,12 @@ Example:
 
     (require hy.contrib.flow)
                 
-    (defn army-greeter [age height]
-        (guard
-            (< age 18) (print "You are too young!")
-            (< height 170) (print "You are too small!")
-            True        (print "Welcome aboard!")))
+    (defn bmi-commenter [bmi]
+        (case bmi
+            10 (print "The bmi was 10, wow.")
+            20 (print "20? Really?")
+            30 (print "Was it 30? Ok...")
+               (print  "I don't even know.")))
 
     
 switch
@@ -54,6 +55,6 @@ Example:
         (switch bmi
             (<= 18.5) (print "you are underweight!")
             (<= 25.0) (print "apparently normal")
-            (<= 30) (print "a little too heavy, but ok")
-                     (print  "You are a whale!")))
+            (<= 30.0) (print "a little too heavy, but ok")
+                      (print  "You are a whale!")))
     

hy/contrib/flow.hy

@@ -1,15 +1,5 @@
 ;; Additional flow macros
 
-(defmacro/g! guard [&rest args]
-  (setv g!cond (car args))
-  (setv g!body (car (cdr args)))
-  (setv g!rest (cdr (cdr args)))
-  (if g!rest
-  `(if ~g!cond
-       ~g!body
-       (guard ~@g!rest))
-  `(if ~g!cond
-       ~g!body)))
 
 (defmacro/g! switch [variable &rest args]
   (setv g!comp (car args))
@@ -22,3 +12,13 @@
         `(if  ~g!cond ~g!body ~@g!rest))
       `(if  ~g!cond ~g!body)))
 
+(defmacro/g! case [variable &rest args]
+  (setv g!value (car args))
+  (setv g!body (car (cdr args)))
+  (setv g!rest (cdr (cdr args)))
+  (setv g!cond `(= ~variable ~g!value))
+  (if g!rest
+      (if (cdr g!rest)
+        `(if ~g!cond ~g!body (case ~variable ~@g!rest))
+        `(if  ~g!cond ~g!body ~@g!rest))
+      `(if  ~g!cond ~g!body)))