Fundamental Redesign of Evaluation

MathPad/MPFunction.h

@@ -26,7 +26,7 @@
 
 
 
-@class MPFunction, MPExpression, MPRangePath;
+@class MPFunction, MPExpression, MPRangePath, MPFunctionTerm;
 @protocol MPExpressionElement;
 
 
@@ -241,6 +241,12 @@
  */
 - (void)didChangeChildAtIndex:(NSUInteger)index;
 
+
+#pragma mark Evaluating Functions
+
+
+- (BOOL)expectsVariableDefinitionInChildAtIndex:(NSUInteger)index;
+
 @end
 
 
@@ -256,6 +262,10 @@
  */
 @interface MPFunction (MPSubclassOverride)
 
+/* In Addition to the methods listed below MPFunction subclasses should also
+ * override the NSObject methods -description and -hash.
+ */
+
 #pragma mark Working With the Expression Tree
 /*!
  @methodgroup Working With the Expression Tree
@@ -281,40 +291,6 @@
  @methodgroup Evaluating Functions
  */
 
-
-/*!
-    @method     validate:
-    @brief      Validates the function and all its children for syntax errors.
- 
-    @param      error
-                If the validation fails this parameter should be set to an
-                appropriate value.
- 
-    @return     @c YES if the validation was successful, @c NO otherwise.
- */
-- (BOOL)validate:(NSError *__autoreleasing *)error;
-
-
-/*!
-    @method     evaluate:
-    @brief      Evaluates the function.
- 
-    @discussion Function evaluation should actually perform math. Also the
-                implementation of this method assumes that the function and all
-                children are valid (as determined by the @c -validate: method).
- 
-    @param      error
-                If a mathematical error occurs it is reflected in this parameter.
-                Depending on the error this method then either returns @c nil or
-                @c NaN.
- 
-    @return     The result of the evaluation or @c nil or @c NaN if an evaluation
-                error occured (such as a division by @c 0).
- */
-- (NSDecimalNumber *)evaluate:(NSError *__autoreleasing *)error;
-
-/* In Addition to the above methods MPFunction subclasses should also override
- * the NSObject methods -description and -hash.
- */
+- (Class)functionTermClass;
 
 @end