Re:Closures and Objects Are Equivalent (2013)
by int_19h on Sunday November 20, 2022 @04:58PM
(#33685860)
Function pointer types are a Turbo Pascal extension; in standard (Wirth/ISO) Pascal, you cannot have "type = function" etc, you can only use that syntax to declare arguments of function type. So they're not first-class values. They're closures because they capture the enclosing environment (variables).
In your second example, what you're doing is the equivalent of reinterpret_cast between two incompatible pointer types (if they were compatible, you could have just assigned @sub to a variable of type MyFuncHidden). You cannot safely assume that your new signature faithfully corresponds to what the compiler does under the hood - that's an implementation detail. Furthermore, in this case, your function doesn't even try to access variables from the outer scope, and this would break if it did.
In your second example, what you're doing is the equivalent of reinterpret_cast between two incompatible pointer types (if they were compatible, you could have just assigned @sub to a variable of type MyFuncHidden). You cannot safely assume that your new signature faithfully corresponds to what the compiler does under the hood - that's an implementation detail. Furthermore, in this case, your function doesn't even try to access variables from the outer scope, and this would break if it did.