Although thinking, probably only happens in languages where type can change arbitrarily.  Here the type can't change except in a new block, which isn't really changing the type, but creating a new variable with the same name that shadows the old variable.

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On Sun, Apr 8, 2018 at 10:59 AM, Lance Dillonriffraff169@yahoo.com wrote: Just out of curiosity, how does intp() and such work. Say you have int|float x, then x=5.0.   Does intp test the type of the variable, or the type of the contents.  Does intp(x) return true because x is of type int (also of type float), or false because the contents of x (currently 5.0) is float, so not an int at that point. I'm thinking contents, not variable itself, so you can do checks against it.

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The [type]p() functions all test the value in a variable, as does _typeof(), which returns a type value:

int|float x = 0.0; intp(x);

(1) Result: 0

int|float x = 0; intp(x);

(2) Result: 1

_typeof(x);

(3) Result: zero

x = 1.0;

(4) Result: 1.0

_typeof(x);

(5) Result: float

If you want to test the variable type, you can use typeof(), which returns the type of a given something rather than the type of the thing it holds:

typeof(x);

(6) Result: int | float

Type types are pretty interesting, but I’m not sure that there’s a good way to express a type literal for use in comparisons. If, for some reason, you need to see if a variable can hold a given type, you can do something like:

// can x hold a float?

mixed y = 1.0;

// note that we compare the variable type of x with the type of the value held in y, // that way we can change the value in y to test for different types. // // if we just wanted a static comparison, we could typeof() against a variable of the // type we wanted. Also, note that 0 gets a type of its own (zero)

(typeof(x) & _typeof(y)) == _typeof(y);

(8) Result: 1

// can x hold a string?

y = ""; (typeof(x) & _typeof(y)) == _typeof(y);

(10) Result: 0

Maybe grubba can fill in any missing pieces (such as if there’s a way to create type values directly).

Bill

On Apr 8, 2018, at 10:59 AM, Lance Dillon riffraff169@yahoo.com wrote:

Just out of curiosity, how does intp() and such work.

Say you have int|float x, then x=5.0.

Does intp test the type of the variable, or the type of the contents. Does intp(x) return true because x is of type int (also of type float), or false because the contents of x (currently 5.0) is float, so not an int at that point.

I'm thinking contents, not variable itself, so you can do checks against it.

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