ponymix: validate arg count before invoking function

A few changes make this fun and easy:

- Merge the function array into the string to action lookup and return a
  Command instead of simply an enum. A Command is the function and the
  min/max arg count.
- Implement an InRange method for the Range class.
- Add a Dispatch function to convert the string to Command and validate
  the arguments.

This leaves us in a position where the argc parameter to each method is
never used, but maybe some day a command will be added that takes a
range of args rather than a fixed number.

1 files changed, 9 insertions, 1 deletions

diff --git a/pulse.h b/pulse.h
index 9a61108..9bb0733 100644
--- a/pulse.h
+++ b/pulse.h
@@ -102,10 +102,18 @@ template<typename T>
 struct Range {
   Range(T min, T max) : min(min), max(max) {}
 
-  T clamp(T value) {
+  // Clamps a value to the stored range
+  T Clamp(T value) {
     return value < min ? min : (value > max ? max : value);
   }
 
+  // Determine if the passed value is within the range. Returns 0
+  // on success, else -1 if lower than the minimum, and 1 if higher
+  // than the maximum.
+  int InRange(T value) const {
+    return value < min ? -1 : (value > max ? 1 : 0);
+  }
+
   T min;
   T max;
 };