Added/Corrected Documentation

MathPad/MPParenthesisFunction.h

@@ -8,10 +8,28 @@
 
 #import "MPFunction.h"
 
+
+
 @class MPParenthesisFunction, MPExpression;
 
+
+/*!
+    @class      MPParenthesisFunction
+    @brief      A parenthesis function encapsulates a single expression and thus
+                prioritizes it in evaluation.
+ 
+    @discussion Prioritizing the expression means that the complete expression
+                must be evaluated 'as is'. No part of it can be 'used' elsewhere
+                before the parenthesis function has been evaluated.
+ */
 @interface MPParenthesisFunction : MPFunction
 
+/*!
+    @property   expression
+    @brief      The expression encapsulated by the parenthesis.
+ 
+    @discussion The expression must not define a variable.
+ */
 @property (nonatomic, strong) MPExpression *expression;
 
 @end