Exporting Variables from Procedures

[Mr. T]

code:

procedure test (var a : int)     a := 3 end test put a

Clearly this won't work because the variable 'a' only exists in its own little procedure world. But let's say there's an instance when i need to export a variable (along with its value) from a procedure. How would I go about doing this?

[wtd]

Ok, so you have...

code:

procedure test (var a : int)     a := 3 end test

Now, let's declare a variable.

code:

var foo : int := 42

Now, let's pass it to the procedure.

code:

test (foo)

Now, let's see what the value of "foo" is.

code:

put foo

[Mr. T]

Ok, but doesn't doing that render a := 3 inside the procedure useless?

[Cervantes]

No, it is not useless. It will change the value of the variable you pass to it (foo, in this case).

However, this is a terrible practice. Parameters are good, but when the procedure is allowed to change the value of the variables you pass in as parameters, you've got a situation almost as bad as global variables.

If you want to change the value of 'foo', don't do it from within the procedure. Rather, make your procedure a function and use that.

code:

function test : int     result 3 end test var foo : int := 42 put foo foo := test put foo

output wrote:

42
3

[Mr. T]

Thanks.