Update index.dd

Comments and a bit smaller

Author: Imperatorn

index.dd

@@ -234,19 +234,14 @@ void main()
 {
     import std.stdio, std.string, std.algorithm, std.conv;
 
-    // Reduce the RPN expression using a stack
-    readln.split.fold!((stack, op)
+    // arr is real[] and sym is the current symbol
+    readln.split.fold!((arr, sym) 
     {
-        switch (op)
-        {
-            // Generate operator switch cases statically
-            static foreach (c; "+-*/")
-                case [c]:
-                    return stack[0 .. $ - 2] ~
-                        mixin("stack[$ - 2] " ~ c ~
-                            " stack[$ - 1]");
-            default: return stack ~ op.to!real;
-        }
+        static foreach (c; "+-*/")
+            if (sym == [c])
+                return mixin("arr[0 .. $-2] ~ (arr[$-2] " ~ c ~ " arr[$-1])");
+
+        return arr ~ sym.to!real;
     })((real[]).init).writeln;
 }
 ----