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  1. using System;
  2. using System.Linq;
  3. using System.Linq.Expressions;
  4.  
  5. public class Test
  6. {
  7. 	public static void Main()
  8. 	{
  9.         Expression<Func<float,float,float>> f1 = (x, y) => x + y;
  10.         Expression<Func<float,float>> f2 = x => x * x;
  11.         var pX = f2.Parameters[0];
  12.         var pY = f1.Parameters[1];
  13.         var replacerF2 = new ReplaceParameter(pX, pY);
  14.         var replacerF1 = new ReplaceParameter(pY, replacerF2.Visit(f2.Body));
  15.         var modifiedF1 = Expression.Lambda(
  16.         	replacerF1.Visit(f1.Body)
  17.         ,   f1.Parameters
  18.         );
  19.         Console.WriteLine(modifiedF1);
  20. 	}
  21.  
  22. 	class ReplaceParameter : ExpressionVisitor {
  23. 		private readonly Expression replacement;
  24. 		private readonly ParameterExpression parameter;
  25. 		public ReplaceParameter(
  26. 		    ParameterExpression parameter
  27.     	,	Expression replacement
  28. 		) {
  29. 			this.replacement = replacement;
  30. 			this.parameter = parameter;
  31. 		}
  32. 		protected override Expression VisitParameter(ParameterExpression node) {
  33. 			return node == parameter ? replacement : node;
  34. 		}
  35. 	}
  36. }
Success #stdin #stdout 0.02s 132800KB
comments (?)
stdin 
Standard input is empty
stdout 
(x, y) => (x + (y * y))
https://ideone.com/L3OoXp
language:
C# (gmcs 5.20.1)
created:
6 years ago
visibility:
public

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