Applies `RewindOnChange` to a default rule set to enable complex, multi-rule transformations for a custom `Average` function.

ID: 981

See: Introduction, RewindOnChange = [bool] 
				
					using uCalcSoftware;

var uc = new uCalc();
var t = uc.ExpressionTransformer;

// Enable rewind for all subsequent rules in this transformer.
t.DefaultRuleSet.SetRewindOnChange(true);

// Define the recursive rules.
t.FromTo("AddUp({x})", "{x}");
t.FromTo("AddUp({x}, {y})", "({x} + AddUp({y}))");

t.FromTo("ArgCount({x})", "1");
t.FromTo("ArgCount({x}, {y})", "(1 + ArgCount({y}))");

// The main rule that combines the others.
t.FromTo("Average({x}, {y})", "AddUp({x}, {y}) / ArgCount({x}, {y})");

var expression = "Average(1, 2, 3, 4)";
Console.WriteLine($"Input: {expression}");
Console.WriteLine($"Transform: {t.Transform(expression)}");
Console.WriteLine($"Eval: {uc.Eval(expression)}");
				
			
Input: Average(1, 2, 3, 4)
Transform: (1 + (2 + (3 + 4))) / (1 + (1 + (1 + 1)))
Eval: 2.5
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					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   auto t = uc.ExpressionTransformer();

   // Enable rewind for all subsequent rules in this transformer.
   t.DefaultRuleSet().SetRewindOnChange(true);

   // Define the recursive rules.
   t.FromTo("AddUp({x})", "{x}");
   t.FromTo("AddUp({x}, {y})", "({x} + AddUp({y}))");

   t.FromTo("ArgCount({x})", "1");
   t.FromTo("ArgCount({x}, {y})", "(1 + ArgCount({y}))");

   // The main rule that combines the others.
   t.FromTo("Average({x}, {y})", "AddUp({x}, {y}) / ArgCount({x}, {y})");

   auto expression = "Average(1, 2, 3, 4)";
   cout << "Input: " << expression << endl;
   cout << "Transform: " << t.Transform(expression) << endl;
   cout << "Eval: " << uc.Eval(expression) << endl;
}
				
			
Input: Average(1, 2, 3, 4)
Transform: (1 + (2 + (3 + 4))) / (1 + (1 + (1 + 1)))
Eval: 2.5
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					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      Dim t = uc.ExpressionTransformer
      
      '// Enable rewind for all subsequent rules in this transformer.
      t.DefaultRuleSet.SetRewindOnChange(true)
      
      '// Define the recursive rules.
      t.FromTo("AddUp({x})", "{x}")
      t.FromTo("AddUp({x}, {y})", "({x} + AddUp({y}))")
      
      t.FromTo("ArgCount({x})", "1")
      t.FromTo("ArgCount({x}, {y})", "(1 + ArgCount({y}))")
      
      '// The main rule that combines the others.
      t.FromTo("Average({x}, {y})", "AddUp({x}, {y}) / ArgCount({x}, {y})")
      
      Dim expression = "Average(1, 2, 3, 4)"
      Console.WriteLine($"Input: {expression}")
      Console.WriteLine($"Transform: {t.Transform(expression)}")
      Console.WriteLine($"Eval: {uc.Eval(expression)}")
   End Sub
End Module
				
			
Input: Average(1, 2, 3, 4)
Transform: (1 + (2 + (3 + 4))) / (1 + (1 + (1 + 1)))
Eval: 2.5
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