changed recipe to plotrecipe and improved it

src/Plots.jl

@@ -144,8 +144,8 @@ export
     arcdiagram,
     chorddiagram,
 
-    @kw,
-    @recipe,
+    # @kw,
+    @plotrecipe,
 
     translate,
     translate!,

src/recipes.jl

@@ -32,8 +32,18 @@ macro kw(k, v)
     esc(:(get!(d, $k, $v)))
 end
 
-macro recipe(args...)
-    expr = args[end]
+macro plotrecipe(args, expr)
+    if !isa(args, Expr)
+        error("The first argument to `@plotrecipe` should be a valid argument list for dispatch.")
+    end
+
+    # wrap the args in a tuple
+    if args.head != :tuple
+        args = Expr(:tuple, args)
+    end
+
+    # replace all the key => value lines with argument setting logic
+    # TODO: when this is moved out of Plots, also move the replacement of key aliases to just after the _apply_recipe calls
     for (i,e) in enumerate(expr.args)
         if isa(e,Expr) && e.head == :(=>)
             k, v = e.args[1:2]
@@ -41,19 +51,19 @@ macro recipe(args...)
         end
     end
 
-    e = esc(quote
-        function Plots._apply_recipe(d::KW, $(args[1:end-1]...); kw...)
-            $expr
+    # now build a function definition for _apply_recipe, wrapping the return value in a tuple if needed
+    esc(quote
+        function Plots._apply_recipe(d::KW, $(args.args...); kw...)
+            ret = $expr
+            if typeof(ret) <: Tuple
+                ret
+            else
+                (ret,)
+            end
         end
     end)
-    # @show e
-    # dump(e,10)
-    e
 end
 
-# macro force_kw(k, v)
-#     esc(:(d[$k] = $v))
-# end
 
 # ---------------------------------------------------------------------------