Could somebody explain the following declaration in a way that conveys the meaning of the expression and how it would be called?
void Delete<T>(Expression<Func<T, bool>> expression) where T : class, new();
I read it as:
Delete an object of type T, by passing in a lambda expression whose parameter is an object of type T that returns a bool.
Also, can you replace
Func<T, bool> expression
with
Predicate<T> expression
The first is a method which accepts an expression tree (not necessarily created from a lambda expression tree). The expression tree represents an expression which accepts a T and returns a bool. T is constrained to be a reference type with a parameterless constructor.
As for the semantic meaning - that's up to the documentation/implementation.
It's important to distinguish between a lambda expression, which is one way of creating an expression tree, and an expression tree itself.
As for whether it could use Predicate<T> instead - maybe. It depends on what the implementation does with it. They represent the same delegate signature, certainly - but you can't convert between the two types of expression tree trivially.