1st Time User Gambas Questions(Former VB6 user)
Posted
#1
(In Topic #296)
Trainee
I recently got into linux and now im exploring my way through gambas which was the closes thing i could find similar to VB6. I've search the net of ways to translate vb6 Type Statement to Gambas which only uses TypeOF and all i can find are types datatypes unrelated to what im trying to achive. So the question is, how does gambas do things like the way VB6 translates this?
Code
Public DataStuff as DataStruct
Private Type DataStruct
a as string
b as byte
c as integer
d as long
End Type
Question 2:
I've started tinkering with "Public Const" stuff and what's got me stumped is that Gambas doesn't like the way this is written.
Code
Public Const White as byte = 1
Public Const SayColor as byte = White
Is there a logical way of making Gambas understand that "White" is declared as a numeric value?
The error presented as follows: <COLOR color="#FF0000">Type Mismatch in modConstants.module:137</COLOR>
Posted
Regular

Europaeus sum !
<COLOR color="#FF8000">Amare memorentes atque deflentes ad mortem silenter labimur.</COLOR>
<COLOR color="#FF8000">Amare memorentes atque deflentes ad mortem silenter labimur.</COLOR>
Posted
Expert

http://gambaswiki.org/wiki/lang/structdecl
When using embedded structures, or embedded arrays of structure, the interpreter has to create temporary objects so that you can manipulate them like real objects. And this is slower!
Consequently, DON'T USE STRUCTURES, UNLESS YOU HAVE TO! For example, to communicate with a shared C-library function that requires C structures.
and
If you declare the same structure in two different classes, they must have exactly the same fields, otherwise the interpreter will raise an error.
Personally, I prefer to create a small class now than use a STRUCT as it gives so much more extensibility.
Cheers - Quin.
I code therefore I am
I code therefore I am
Posted
Trainee
Quincunxian said
Some information from the Gambas Wiki on STRUCT:
http://gambaswiki.org/wiki/lang/structdecl
When using embedded structures, or embedded arrays of structure, the interpreter has to create temporary objects so that you can manipulate them like real objects. And this is slower!
Consequently, DON'T USE STRUCTURES, UNLESS YOU HAVE TO! For example, to communicate with a shared C-library function that requires C structures.
and
If you declare the same structure in two different classes, they must have exactly the same fields, otherwise the interpreter will raise an error.
Personally, I prefer to create a small class now than use a STRUCT as it gives so much more extensibility.
vuott said
For the project im doing its actually needed. If you can show me a psuedo code that would help a lot.
Hello,
1st answer:
/lang/structdecl - Gambas Documentation
2nd answer:
Not variables and only certain native datatypes can be assigned.
/lang/constdecl - Gambas Documentation
However, remember that Gambas is not a VB emulation.
Thanks for that, I found this link last minute before I saw this post.
As for the 2nd answer, thats disappointing, would of saved me a lot of time remembering values for calculations. it looks like im going to have to type out long codes everytime i set arguements…
Posted
Trainee
Quincunxian said
Some information from the Gambas Wiki on STRUCT:
http://gambaswiki.org/wiki/lang/structdecl
When using embedded structures, or embedded arrays of structure, the interpreter has to create temporary objects so that you can manipulate them like real objects. And this is slower!
Consequently, DON'T USE STRUCTURES, UNLESS YOU HAVE TO! For example, to communicate with a shared C-library function that requires C structures.
and
If you declare the same structure in two different classes, they must have exactly the same fields, otherwise the interpreter will raise an error.
Personally, I prefer to create a small class now than use a STRUCT as it gives so much more extensibility.
vuott said
Hello,
1st answer:
/lang/structdecl - Gambas Documentation
2nd answer:
Not variables and only certain native datatypes can be assigned.
/lang/constdecl - Gambas Documentation
However, remember that Gambas is not a VB emulation.
Thanks for that, I found this link last minute before I saw this post.
As for the 2nd answer, thats disappointing, would of saved me a lot of time remembering values for calculations. it looks like im going to have to type out long codes everytime i set arguements…
For the project im doing its actually needed. If you can show me a psuedo code that would help a lot.
Posted
Trainee
Regards, Lavos
Posted
Regular

If you want a suggestion for another similar IDE for Linux, you may want to look into Lazarus. Very similar RAD environment for building GUI applications, if you are willing to adapt to Pascal.
Posted
Trainee
Technopeasant said
Often Gambas is merely differently implemented than VB, rather than neccesairly feature incomplete, but I can not speak for your project in particular.
If you want a suggestion for another similar IDE for Linux, you may want to look into Lazarus. Very similar RAD environment for building GUI applications, if you are willing to adapt to Pascal.
Interesting, I looked up Lazarus and it does look appealing to me. I'll probably play around with it sometime soon.
As for Gambas, I find Gambas Method of Syntax very odd and inflexible, restricted, limited.
Here are some of my baffling examples…
<IMG src="https://i.imgur.com/SXlzdQX.png">
</IMG><IMG src="https://i.imgur.com/sL0j7Bs.png">
</IMG><IMG src="https://i.imgur.com/opjAsJa.png">
</IMG>I spent a while reading up on the documentation… it's meh… and the strangest part is having to use an address or key?, to a module or class to call a function or routine.
Posted
Guru

The first error you show is caused by you trying to do a 'Dir', which requires a directory, and you are suppling a filename.
Looking at the code you are trying to find if a file exists and the best way to do that is with the 'Exist' command.
You can use &/ to join 2 paths together and you wont have to worry about the slash. The following lines produce the same result:-
Posted
Trainee
cogier said
Hi Lavos,
The first error you show is caused by you trying to do a 'Dir', which requires a directory, and you are suppling a filename.
Looking at the code you are trying to find if a file exists and the best way to do that is with the 'Exist' command.
You can use &/ to join 2 paths together and you wont have to worry about the slash. The following lines produce the same result:-
I've read the documentations about how using exist command works and played around with it before you made this post. It seems to work just fine when i swapped out Dir using File.Dir to see if the file exists.
Do you have any idea why I can't manipulate a Boolean function within its scope?
<IMG src="http://i.imgur.com/ujTjXdF.png">
</IMG>
Posted
Expert

Cheers - Quin.
I code therefore I am
I code therefore I am
Posted
Trainee
Quincunxian said
Hi Lavos - can you post the code in modDatabase where .FileExist is declared please.
<IMG src="https://i.imgur.com/GwaKlr9.png">
</IMG>Does this helps? 8-)
Posted
Guru

Posted
Expert

Cheers - Quin.
I code therefore I am
I code therefore I am
Posted
Trainee
Thank you. That makes more sense. I'm still in a habit of coding in vb6. I'm still really trying hard to adapt to gambas way of understanding how it works.<EMOJI seq="1f60e">😎</EMOJI>cogier said
Anyway ive read the documentation for structs time and time again because it imo, vague… so im jyst gunna ask, is it possible to pass a value through structs? Im just trying to avoid using a class according programming standards, using class as a replacment for UDTs (structs) is bad practice.
-regards, Lavos and the community.
Posted
Trainee
Lavos said
Thank you. That makes more sense. I'm still in a habit of coding in vb6. I'm still really trying hard to adapt to gambas way of understanding how it works.<EMOJI seq="1f60e">😎</EMOJI>cogier said
Anyway ive read the documentation for structs time and time again because it imo, vague… so im jyst gunna ask, is it possible to pass a value through structs? Im just trying to avoid using a class because according programming standards, using class as a replacment for UDTs (structs) is bad practice.
-regards, Lavos and the community.
Posted
Guru

What are you trying to acheive? Pehaps we can find an alternative.
Posted
Regular

First a general comment for Lavos: I, too, am a long time VB6 (actually VB3-6) user and I found Gambas at the beginning of the year. My impression has been very very favorable. I see Gambas as a big improvement over VB6, sort of like VB done right. I joke it should have been called "Inc VB" (a word play on C++).
Having said that, there are a few things I would have liked to have been done differently. Foremost, is the lack of a line continuation character. I have requested it and it has been deemed too difficult to implement. I hope this is rectified in the future. I do find it a little annoying to have to dim all my variables, I would like to see either type declaration characters used (like VB), or a default type of Integer (instead of Single like orginal BASICs).
Those are the major ones.
Hitting the issues raised in this thread:
I much prefer having "Return (value)" rather than "(function_Name) = (value)" as the way to return values from a call. It would be nice to be able to return multiple values like Python can, but again, this has been deemed too difficult. Multiple values can be returned by either ByRef arguments (which are not the default like VB) or returning an object or an array. Unfortunately, this use of "Return" clashes with the "Return" used for a GoSub. I would have preferred a different word for the latter, perhaps "GoBack". The compiler can figure it out, but for readability I think different syntax should have been used. I am a huge fan of GoSubs and consider them one of the things that makes BASICs superior to other languages. Inherent readability being another.
The use of user defined structures is discouraged because I believe they make memory manager tougher, not sure about that though. There is difficulty in matching the packing rules between Gambas definitions and what an underlying language does (like C or FORTRAN external library calls), so structs may not match. I have never heard that it is poor programming practice to use a class when a struct would do. I am curious to what the motivation for that might be or where you have heard it.
Out of curiosity, who is your "community"?
Regards,
Ced
.... and carry a big stick!
Posted
Expert

In this example:
Try {some task}
Return {Result}
Finally
{Do some closing task}
Catch
{Handle Error}
In the case of no error occurring, the Return statement works as required but the Finally statement never triggers leaving any 'final' tasks undone. The Function essentially Quits as soon as the Return statement is met.
When you have error trapping in a Function it is better to do this:
Dim ReturnValue as {Required data Type}
Try {some task}
Return Value = {Result}
Finally
{Do some closing task}
Return ReturnValue
Catch
{Handle Error}
Cheers - Quin.
I code therefore I am
I code therefore I am
Posted
Trainee
cogier said
I have never used structs as Gambas says in capitals 'DON'T USE STRUCTURES, UNLESS YOU HAVE TO!'
What are you trying to acheive? Pehaps we can find an alternative.
Yes, that would be nice! I'll be sure to share when I find something out.
Cedron said
I've been busy for a little while so I have left this thread alone.
First a general comment for Lavos: I, too, am a long time VB6 (actually VB3-6) user and I found Gambas at the beginning of the year. My impression has been very very favorable. I see Gambas as a big improvement over VB6, sort of like VB done right. I joke it should have been called "Inc VB" (a word play on C++).
Having said that, there are a few things I would have liked to have been done differently. Foremost, is the lack of a line continuation character. I have requested it and it has been deemed too difficult to implement. I hope this is rectified in the future. I do find it a little annoying to have to dim all my variables, I would like to see either type declaration characters used (like VB), or a default type of Integer (instead of Single like orginal BASICs).
Those are the major ones.
Hitting the issues raised in this thread:
I much prefer having "Return (value)" rather than "(function_Name) = (value)" as the way to return values from a call. It would be nice to be able to return multiple values like Python can, but again, this has been deemed too difficult. Multiple values can be returned by either ByRef arguments (which are not the default like VB) or returning an object or an array. Unfortunately, this use of "Return" clashes with the "Return" used for a GoSub. I would have preferred a different word for the latter, perhaps "GoBack". The compiler can figure it out, but for readability I think different syntax should have been used. I am a huge fan of GoSubs and consider them one of the things that makes BASICs superior to other languages. Inherent readability being another.
The use of user defined structures is discouraged because I believe they make memory manager tougher, not sure about that though. There is difficulty in matching the packing rules between Gambas definitions and what an underlying language does (like C or FORTRAN external library calls), so structs may not match. I have never heard that it is poor programming practice to use a class when a struct would do. I am curious to what the motivation for that might be or where you have heard it.
Out of curiosity, who is your "community"?
Regards,
Ced
I'm relieved to see a fellow VB user on this forum, I can relate to your experiences and somewhat understand your opinions of comparing Gambas and VB. To answer your curiosity, people on other programming communities explain tests being done with comparing UDTs vs Classes, UDTs speeds are faster than using Class declarations according to my research from other forums, Jonathan S. Harbour said the same things with his books a while back, I forget which one was that though.
The community? I speak for those who are trying for an alternative to VB, the ones who are transitioning from Microsoft Windows to Linux. It seems like Gambas might be the answer.
Visit me in on my community "here"
Quincunxian said
There is a small issue with the Return statement when used with Try/Catch/Finally Error management.
In this example:
Try {some task}
Return {Result}
Finally
{Do some closing task}
Catch
{Handle Error}
In the case of no error occurring, the Return statement works as required but the Finally statement never triggers leaving any 'final' tasks undone. The Function essentially Quits as soon as the Return statement is met.
When you have error trapping in a Function it is better to do this:
Dim ReturnValue as {Required data Type}
Try {some task}
Return Value = {Result}
Finally
{Do some closing task}
Return ReturnValue
Catch
{Handle Error}
Thanks for sharing, I'll get right into playing around with this reference.
Posted
Trainee
Lavos said
cogier said
I have never used structs as Gambas says in capitals 'DON'T USE STRUCTURES, UNLESS YOU HAVE TO!'
What are you trying to acheive? Pehaps we can find an alternative.
Yes, that would be nice! I'll be sure to share when I find something out.
Cedron said
I've been busy for a little while so I have left this thread alone.
First a general comment for Lavos: I, too, am a long time VB6 (actually VB3-6) user and I found Gambas at the beginning of the year. My impression has been very very favorable. I see Gambas as a big improvement over VB6, sort of like VB done right. I joke it should have been called "Inc VB" (a word play on C++).
Having said that, there are a few things I would have liked to have been done differently. Foremost, is the lack of a line continuation character. I have requested it and it has been deemed too difficult to implement. I hope this is rectified in the future. I do find it a little annoying to have to dim all my variables, I would like to see either type declaration characters used (like VB), or a default type of Integer (instead of Single like orginal BASICs).
Those are the major ones.
Hitting the issues raised in this thread:
I much prefer having "Return (value)" rather than "(function_Name) = (value)" as the way to return values from a call. It would be nice to be able to return multiple values like Python can, but again, this has been deemed too difficult. Multiple values can be returned by either ByRef arguments (which are not the default like VB) or returning an object or an array. Unfortunately, this use of "Return" clashes with the "Return" used for a GoSub. I would have preferred a different word for the latter, perhaps "GoBack". The compiler can figure it out, but for readability I think different syntax should have been used. I am a huge fan of GoSubs and consider them one of the things that makes BASICs superior to other languages. Inherent readability being another.
The use of user defined structures is discouraged because I believe they make memory manager tougher, not sure about that though. There is difficulty in matching the packing rules between Gambas definitions and what an underlying language does (like C or FORTRAN external library calls), so structs may not match. I have never heard that it is poor programming practice to use a class when a struct would do. I am curious to what the motivation for that might be or where you have heard it.
Out of curiosity, who is your "community"?
Regards,
Ced
I'm relieved to see a fellow VB user on this forum, I can relate to your experiences and somewhat understand your opinions of comparing Gambas and VB. To answer your curiosity, people on other programming communities explain tests being done with comparing UDTs vs Classes, UDTs speeds are faster than using Class declarations according to my research from other forums, Jonathan S. Harbour said the same things with his books a while back, I forget which one was that though.
The community? I speak for those who are trying for an alternative to VB, the ones who are transitioning from Microsoft Windows to Linux. It seems like Gambas might be the answer.
Visit me in on my community "here"
Quincunxian said
There is a small issue with the Return statement when used with Try/Catch/Finally Error management.
In this example:
Try {some task}
Return {Result}
Finally
{Do some closing task}
Catch
{Handle Error}
In the case of no error occurring, the Return statement works as required but the Finally statement never triggers leaving any 'final' tasks undone. The Function essentially Quits as soon as the Return statement is met.
When you have error trapping in a Function it is better to do this:
Dim ReturnValue as {Required data Type}
Try {some task}
Return Value = {Result}
Finally
{Do some closing task}
Return ReturnValue
Catch
{Handle Error}
Thanks for sharing, I'll get right into playing around with this reference.
I wonder if there is a community-driven documentation for Gambas, some parts of it are so vague but i read it over and over again hoping i get something out of it…
Posted
Regular

Lavos said
I'm relieved to see a fellow VB user on this forum, I can relate to your experiences and somewhat understand your opinions of comparing Gambas and VB. To answer your curiosity, people on other programming communities explain tests being done with comparing UDTs vs Classes, UDTs speeds are faster than using Class declarations according to my research from other forums, Jonathan S. Harbour said the same things with his books a while back, I forget which one was that though.
The community? I speak for those who are trying for an alternative to VB, the ones who are transitioning from Microsoft Windows to Linux. It seems like Gambas might be the answer.
Visit me in on my community "here"
Hmmmmmmmmm, classes being slower than UDTs has to be a platform/language specific thing. In theory, and in practice in many places, a class is simply a structure with an associated set of routines and the address of the instance implicitly passed as the first parameter. You can do it explicitly if you like, and I have many times, including recently when C was specified and C++ not allowed.
If you are looking for speed alone, Gambas is not the answer. It is is a byte code interpreter (like Python, Java, VB1-3, and optional in VB4). However, it is very easy to call shared libraries from Gambas which makes up for this. I have posted many examples of shared libraries in this forum, you may want to look at those.
I took a look at your community. I couldn't find any "About Eclipse Engine" to explain what it is about. My first thought was it had to do with the Eclipse IDE, but that does not appear to be the case. It looks like a game developers forum of some type.
If you are interested in using Gambas for game development, you might want to look at this thread:
Gambas One - Gambas ONE
I also have a shared library for accessing gamepads that I have not posted yet.
Ced
.... and carry a big stick!
Posted
Trainee
I'm on a windows machine when i posted this, so any request of posting codes, i'd be happy too when i get to my linux machine.
-Regards, Lavos
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