The dynamic language runtime (DLR) has some pretty cool code for Expression's, including some very nice code to print out Expression trees which I want to use so that:

```
int a = 1;
int b = 2;
Expression<Func<int, int>> expression = (c) => a + (b * c)
expression.Evaluate(5, stringBuilder)
```

Outputs:

```
(5) => a + (b * c) = 11 Where
a = 1
b * c = 10 Where
b = 2
c = 5
```

I found some code on the net to do this but found that it only works if the expressiontakes in no arguments.

I then discovered the DLR implementation of a similar method. However the DLR has its own custom implementations of the Expression class and many other standard C# types so I got a little confused. Anyone know how I can implement the above?

How about:

```
using System;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using System.Text.RegularExpressions;
static class Program
{
static void Main()
{
int a = 1, b = 2;
StringBuilder sb = new StringBuilder();
Expression<Func<int, int>> expression = (c) => a + (b * c);
expression.Evaluate(sb, 5);
// now fix the capture class names (from a and b)
string s = sb.ToString();
s = Regex.Replace(s, @"value\([^)]+\)\.", "");
Console.WriteLine(s);
}
public static void Evaluate(this LambdaExpression expr, StringBuilder builder, params object[] args)
{
var parameters = expr.Parameters.ToArray();
if (args == null || parameters.Length != args.Length) throw new ArgumentException("args");
Evaluate(expr.Body, 0, builder, parameters, args);
}
private static StringBuilder Indent(this StringBuilder builder, int depth)
{
for (int i = 0; i < depth; i++) builder.Append(" ");
return builder;
}
private static void Evaluate(this Expression expr, int depth, StringBuilder builder, ParameterExpression[] parameters, object[] args)
{
builder.Indent(depth).Append(expr).Append(" = ").Append(Expression.Lambda(expr, parameters).Compile().DynamicInvoke(args));
UnaryExpression ue;
BinaryExpression be;
ConditionalExpression ce;
if ((ue = expr as UnaryExpression) != null)
{
builder.AppendLine(" where");
Evaluate(ue.Operand, depth + 1, builder, parameters, args);
}
if ((be = expr as BinaryExpression) != null)
{
builder.AppendLine(" where");
Evaluate(be.Left, depth + 1, builder, parameters, args);
Evaluate(be.Right, depth + 1, builder, parameters, args);
}
else if ((ce = expr as ConditionalExpression) != null)
{
builder.AppendLine(" where");
Evaluate(ce.Test, depth + 1, builder, parameters, args);
Evaluate(ce.IfTrue, depth + 1, builder, parameters, args);
Evaluate(ce.IfFalse, depth + 1, builder, parameters, args);
}
else
{
builder.AppendLine();
}
}
}
```

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