PureBasic Forums - English

One can already define a Structure type inside a procedure:
Unfortunately Structure types are global to the program, so no other "Structure Foo" can be defined elsewhere in the program.

It would be nice if local Structure types could be created by using the Protected keyword or even if local Structure types were really local.

I think, it is because a Struct is a compiler-thingy, so always defined at compile-time.

maybe it would be a solution, if any struct-def will first have placed a header depending on the sub-module.

but in fact..... I dunno a situation where it would be needful to define a struct within a proc.

pls tell me, what you are really after, so I can decide, if I would support your request or argue it away...

@ktamp:
If I understand you correctly, you would like a feature that let's you define a structure in a procedure that restricts its use outside of a procedure. You would want to do this so that you could combine code from different projects or sources together without having to manually find structures that were already defined and rename them.

If this is the case, the compiler already pinpoints where the same structure name is reused in a structure definition. Since the duplicate would be intended to be local to the procedure you can simply rename it there without affecting any other portion of the program or source outside of the procedure in question. To make that easier you could simply add the name of the procedure before the structure name to make it unique.
For this code you could rename the structure Foo to Test__Foo, using two underscores between the procedure name and structure name. Any other decorating of the name that produces unique names would suit the same purpose.

Example I agree with you about the benefit of having the compiler generate the decoration of the local structure name, but the work around is also easy enough to perform. You would just make it a habit of creating the decorated name when the procedure is written, or scanning code that is going to be combined together for declarations within procedures and renaming them at that time.

Since Structure definitions are global to the program, and not to Procedures, there should be forbidden to define structures inside Procedures, "imho".

Since Structure definitions are global to the program, and not to Procedures, there should be forbidden to define structures inside Procedures, "imho".

Since this is a Feature Request we are referring to what is desired, not what currently is.

They currently are global and should thus find reason to be forbidden, at present. However, they can currently be declared in a procedure the same way as a global variable declaration: With variables, they are treated as local if declared in a procedure unless they are specified Global. I don't see why this could not be accomodated for Structure declarations also. Perhaps like this:
Perhaps the reverse would work better, "Local Structure". In that case it would be assumed to be Global unless declared local. I would favor a single keyword such as Global_Structure or Local_Structure instead of a combination of keywords like "Global Structure" or "Local Sturcture."
I would favor more the treating of a Structure definition as local if declared in a Procedure, otherwise it would be global. For naming conflicts where there is a global and a local structure using the same name, the local one would get priority within the procedure.

It sounds to me is what you are looking for is a Module.

There have been discussions in the past about introducing Modules to PB.

http://www.purebasic.fr/english/viewtop ... ght=module

The main request has nothing to do with modules, i think.
@Demivec, you are right, but what i meant is that i second this request, but probably it will be not done by PB team. That's why i wrote:

Psychophanta wrote:Since Structure definitions are global to the program, and not to Procedures, there should be forbidden to define structures inside Procedures, "imho".

Mainly because it is very ugly and inconsistent to see things like:

I agree to GedB:
sounds like "effective Moduling" is what is essentially requested.

Modules requesting pointed by GedB is good, but @Kaeru and @GedB; sorry but ktamp just requests for Structure names to be local to a Procedure (when defined inside it) not global to the program or to a module.
Or do i miss something?

Psychophanta wrote:Modules requesting pointed by GedB is good, but @Kaeru and @GedB; sorry but ktamp just requests for Structure names to be local to a Procedure (when defined inside it) not global to the program or to a module.

That is all ktamp is requesting. Implementing Modules would definately make this possible also. If Modules were implemented it would make this request moot.
I'll just let the idea simmer until a Team member responds to it. I don't think it can be expressed any simpler.

yo, just right.

*billie boiles, now brewing an Earl Gray and handing a cup to Demivec*
let's wait, mate....

I don't fully understand the problem. Structures are just templates and indeed have a global scope - but only so as a template.
Only after instantiating a variable of type 'structure' a variable actually exists and this variable can be local to a procedure.
I understand why keeping variables local is a good thing (tight binding, loose coupling, information hiding, etc. etc.), but what's the use of having local templates?

in fact, exactly the thing this is.
useful local structures would be,
if modules implemented are.

dell_jockey,

Global structures are fine until you want to start reusing stuff.

Lets say that you have a library for looking after your flowers.

This library contains the structure
You also have a lighting library for dealing with all the different types of lamp you have.
Your new project is to use lamps to quick grow your flowers. When you import both the Flower Library and the Light Library you have a name clash.

ok, in the context of libraries that makes sense. Modules could indeed solve this problem.
On the other hand, wouldn't the introduction of namespaces for libraries be a less intrusive solution?