Classes, Unions and Arrays Help Please

[kryton9]

I was thinking about doing that, but then wanted to know if could do it with private. Probably the easiest solution. Will think about it some more.

[Charles Pegge]

Hi Kent,

Private members are quite well guarded.

When dealing with compound math types that use operators, such as vectors, quaternions and matrices, you need efficient access to the individual members, at least for input and output of scalar values.

Oxygen performs automatic conversion between integers, floats and strings, which in many cases, eliminates the need for accessor methods.

Code: OxygenBasic

1. class vec
2.   double x,y,z
3. end class
4.  
5. vec v
6. v<="1.1","2.2","3.3" 'these are converted to doubles automatically
7.  
8. print str(v.x+v.y+v.z,4) 'answer 6.6 (integrity check)
9.  

Charles

[kryton9]

I forget that Oxygen is no ordinary language and compiler, it is Smart++. That will be super then, a lot easier than having to write all the methods to get and set!!

[kryton9]

I need your help oh master of oxygen.

Unzip the attachment to the projects folder. There is a readme.txt file to read and the comments in the code.

Getting this to work could lead to some powerful stuff, at least that is my hope!!

[Charles Pegge]

I made a few minor changes, Kent, but the one to scrutinize is how to hook dynamic objects (of csqlite)into a new class. The new object has to be instantiated inside a method, in this case your constructor.

I've include to techniques for doing it. Solution d is the simplest


new cSqlite lDB ()
@mDB=@lDB 'link to this member

Solution d

Code: OxygenBasic

1.  
2. class cArray
3.     'member variables
4.    private
5.  
6.         string  mName
7.         cSqlite *mdb
8.  
9.     public
10.  
11.         method Constructor( string aName = "AutoTableName" )
12.             new cSqlite lDB ()
13.             @mDB=@lDB 'link to this member
14.            mname=aname
15.             mDB.Exec "create table "mName" ( t text );"
16.         end method
17.        
18.         method Destructor()
19.             del mDB
20.         end method
21.        
22. ....
23.  

[kryton9]

Thanks Charles, it was driving me crazy. I couldn't sleep thinking about it. It is 5 a.m. already. So thanks now I can have some peace and sleep!

One question in solution D, which I agree, I like the best.  What about lDB?  shouldn't that be deleted also in the destructor along with mDB?

[Charles Pegge]

No. In reality, lDB is just a pointer. Once its value is transferred to the mDB pointer, it is redundant.

then mDB takes on the role of the new object.

[kryton9]

Thanks for the explanation. That is a very elegant solution.

[kryton9]

Here is the start of a pretty slick dynamic array using sqlite3 as the backend. Right now it is only in the beginning stages. I am not flushing out any of the classes till I know that the whole idea I have in my mind can be done.

For now it is a single dimensional dynamic array that can hold numbers and strings. You can sort easily in either direction and go through the array with minimal code.

Unzip the attachment into your projects directory.

[kryton9]

Charles, just download, unzip into the projects folder and please read the "Read Me.txt".
Another one I am at a loss.

[Charles Pegge]

Hi Kent, I see a problem with self-referencing. That is: when a member of the class is the class.

If this was a direct member, you would get a recursive explosion, but it should be possible to have a pointered member, as you have in cVec3

class cVec3 
    public 'member vars
        has tVec3
       
    private 'member vars
        cVec3 *mTemp
       


Anyway this will keep me busy for a while.

Charles

[kryton9]

I knew that was going to be tough one. I hate to hit you with it, good luck!

[Charles Pegge]

Hi Kent,

It's been an interesting journey through the hall of mirrors

I've marked up 2 infinite recursions!

Below your program files, a new Oxygen, and an example tree class, which I trust is reasonably proof against unintended recursion.

new tree trunk
let branchA = trunk.CreateBranch 1
let twigA1 = branchA.CreateBranch 1
...
del trunk

Charles

[attachment deleted by admin]

[kryton9]

Charles, I love it. Since we are not using New, then no Del, we are using getmemory and then freememory, so that eliminates confusion on when to use which.

I don't understand this:

Code: OxygenBasic

1.   method ShowAll() as string
2.   tree*tr
3.   sys i
4.   method+=s  ": Coords "  x ", " y ", " z chr(13) chr(10)
5.   for i=1 to branches
6.     if t[i] then
7.       @tr=t[i]
8.       method+=tr.ShowAll() 'RECURSE
9.    end if
10.   next
11.   end method

method+=s  ": Coords "  x ", " y ", " z chr(13) chr(10)
method+=tr.ShowAll() 'RECURSE

I thought method used like that was like return. How can you have +=?  Also on the recurse, won't it exit when it sees the first method? I don't see a conditional to prevent it.

Anyways, I know this must have been a nightmare to solve. But it is making for a tighter better oxygen.

The last 2 days I have been working on 1 million cVec3's, creating, inserting, resorting and getting back the data. Here is the moral of the story:
With a small test, as we have in the cArray that you were using, it was just a few records hand entered. It was no problem. Once I got a good RandDouble function to generate random cVec3's, I started bumping it up. One thousand, no problem. Ten Thousand, no problem. 100 Thousand, about 5 seconds total time, not bad at all. 1 Million about a minute, too slow and that was after optimizing. The original took about 4 minutes at 1 Million. In reading Sqlite3 documentation, they say I should be able to do about 50,000 inserts per second on an average computer. So I am working to get it down to around 20 seconds, with 1 million inserts. With your improvements to the classes, it will help get data in and out faster now.

Thanks again!

[Charles Pegge]

Hi Kent,

it works like function= in PowerBasic. Method is the variable that will be returned at the end of the procedure. In this case it behaves like any other string variable.

No problem with recursion, the string just accumulates the recursed output of levels below. Though it is not the most efficient way of doing it, and a large tree would be better served by using a buffering techniques rather than simple concatenation.

I wouldn't worry too much about speed. Once you have a working system, the bottlenecks will become obvious, and if necessary, we unleash the assembler! But once optimisations are in place, it becomes more difficult to change your program design, so they are best done later in the project.

Charles