public static LambdaExpression Combine(this LambdaExpression outer, LambdaExpression inner)
{
var invoke = Expression.Invoke(inner, outer.Body);
var body = new ExpressionRewriter().AutoInline(invoke);
return Expression.Lambda(body, outer.Parameters.ToArray());
}
internal Expression AutoInline(InvocationExpression expression)
{
this.isLocked = true;
if (expression == null) throw new ArgumentNullException("expression");
var lambda = (LambdaExpression) expression.Expression;
var childScope = new ExpressionRewriter(this);
var lambdaParams = lambda.Parameters;
var invokeArgs = expression.Arguments;
if (lambdaParams.Count != invokeArgs.Count) throw new InvalidOperationException("Lambda/invoke mismatch");
for (int i = 0; i < lambdaParams.Count; i++)
{
childScope.Subst(lambdaParams[i], invokeArgs[i]);
}
return childScope.Apply(lambda.Body);
}
ExpressionRewriter(ExpressionRewriter parent)
{
if (parent == null) throw new ArgumentNullException("parent");
this.subst = new Dictionary<Expression, Expression>(parent.subst);
this.inline = parent.inline;
}