Thursday, February 16, 2012

Create a fast compiled method invoker using LINQ

var method = new Func<double, double, double>(Math.Pow).Method;
var parameter = Expression.Parameter(typeof(object[]));
var args = method.GetParameters()
    .Select((param, i) => Expression.Convert(
        Expression.ArrayIndex(parameter, Expression.Constant(i)), param.ParameterType));
var expr = Expression.Lambda<Func<object[], object>>(
    Expression.Convert(Expression.Call(method, args), typeof(object)), parameter);
var invoker = expr.Compile();
var result = invoker(new object[] {Math.PI, 2.0});

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