Using BaCon's new CLASS command (in the beta version)

[bigbass]

We have a new command CLASS ENDCLASS

I will demo several ways to use this command
and even how to port a code example
from a custom class not related to any GUI toolkit

first some documentation with many details if you need it
if not you can skip it and focus on the code below
www.tutorialspoint.com/cplusplus/cpp_classes_objects.htm


if confronted with this example in C++
and you want to port it let's go
I removed the using namespace std;
then you prefix the cout commands with std::
we don't need to let that get in the way for now



#include <iostream>

// call it class1demo.cxx  then compile and run
//  g++ -O -Wall class1demo.cxx -o app
//  ./app

//using namespace std;

class Box {
  public:
     double length;   // Length of a box
     double breadth;  // Breadth of a box
     double height;   // Height of a box
};

int main() {
  Box Box1;        // Declare Box1 of type Box
  Box Box2;        // Declare Box2 of type Box
  double volume = 0.0;     // Store the volume of a box here

  // box 1 specification
  Box1.height = 5.0;
  Box1.length = 6.0;
  Box1.breadth = 7.0;

  // box 2 specification
  Box2.height = 10.0;
  Box2.length = 12.0;
  Box2.breadth = 13.0;
 
  // volume of box 1
  volume = Box1.height * Box1.length * Box1.breadth;
  std::cout << "Volume of Box1 : " << volume <<std::endl;

  // volume of box 2
  volume = Box2.height * Box2.length * Box2.breadth;
  std::cout << "Volume of Box2 : " << volume <<std::endl;
  return 0;
}





STEP 1
now the simple port just to get it to compile in BaCon
and see if it works correctly
changed the word breadth to width
I commented out the fltk dependency
to show its not needed here




'---PRAGMA LDFLAGS -lfltk -L.
PRAGMA LDFLAGS -lbacon++
PRAGMA COMPILER g++
PRAGMA OPTIONS -Wno-write-strings -Wno-pointer-arith -Wno-permissive
OPTION PARSE FALSE



'--- Show the use of custom class.
'--- using BaCons new CLASS ENDCLASS commmand
PRAGMA INCLUDE <stdio.h>
PRAGMA INCLUDE <string.h>
PRAGMA INCLUDE <stdlib.h>
PRAGMA INCLUDE <iostream>



CLASS Box
  public:
     double length;   // Length of a box
     double width;  // Breadth of a box
     double height;   // Height of a box
ENDCLASS

  '--- Declare Box1 of type Box
  '--- Declare Box2 of type Box
  DECLARE  Box1 TYPE Box  
  DECLARE  Box2 TYPE Box  
     
  '--- Store the volume of a box here
  DECLARE volume TYPE  double    
  volume = 0.0
 
  '--- box 1 set values
  Box1.height = 5.0
  Box1.length = 6.0
  Box1.width = 7.0

  '--- box 2 set values
  Box2.height = 10.0
  Box2.length = 12.0
  Box2.width = 13.0
 
  // volume of box 1
  volume = Box1.height * Box1.length * Box1.width
  std::cout << "Volume of Box1 : " << volume <<std::endl

  // volume of box 2
  volume = Box2.height * Box2.length * Box2.width
  std::cout << "Volume of Box2 : " << volume <<std::endl




STEP2 we start to convert code to use BaCon syntax for the PRINT


'---PRAGMA LDFLAGS -lfltk -L.
PRAGMA LDFLAGS -lbacon++
PRAGMA COMPILER g++
PRAGMA OPTIONS -Wno-write-strings -Wno-pointer-arith -Wno-permissive
OPTION PARSE FALSE



'--- Show the use of custom class.
'--- using BaCons new CLASS ENDCLASS commmand
PRAGMA INCLUDE <stdio.h>
PRAGMA INCLUDE <string.h>
PRAGMA INCLUDE <stdlib.h>
PRAGMA INCLUDE <iostream>



CLASS Box
  public:
     double length;   // Length of a box
     double width;  // Breadth of a box
     double height;   // Height of a box
ENDCLASS

  '--- Declare Box1 of type Box
  '--- Declare Box2 of type Box
  DECLARE  Box1 TYPE Box  
  DECLARE  Box2 TYPE Box  
     
  '--- Store the volume of a box here
  DECLARE volume TYPE  double    
  volume = 0.0
 
  '--- box 1 set values
  Box1.height = 5.0
  Box1.length = 6.0
  Box1.width = 7.0

  '--- box 2 set values
  Box2.height = 10.0
  Box2.length = 12.0
  Box2.width = 13.0
 
  '--- volume of box 1
  volume = Box1.height * Box1.length * Box1.width
  PRINT "Volume of Box1 : " , volume

  '--- volume of box 2
  volume = Box2.height * Box2.length * Box2.width
  PRINT "Volume of Box2 : " , volume



STEP 3 we also need to know how to convert .member syntax
to arrow operator -> syntax because this is widely used in C++
another way to think about this is everything points back to the CLASS
the CLASS is your customised TYPE that you created all neat in one place


'---PRAGMA LDFLAGS -lfltk -L.
PRAGMA LDFLAGS -lbacon++
PRAGMA COMPILER g++
PRAGMA OPTIONS -Wno-write-strings -Wno-pointer-arith -Wno-permissive
OPTION PARSE FALSE



'--- Show the use of custom class.
'--- using BaCons new CLASS ENDCLASS commmand
'--- if you want to use C code printf
PRAGMA INCLUDE <stdio.h>
PRAGMA INCLUDE <string.h>
PRAGMA INCLUDE <stdlib.h>
'--- C++ style cout
PRAGMA INCLUDE <iostream>



CLASS Box
  public:
     double length;   // Length of a box
     double width;  // Breadth of a box
     double height;   // Height of a box
ENDCLASS

  '--- Declare Box1 of type Box
  '--- Declare Box2 of type Box
  DECLARE  Box1 TYPE Box*  
  DECLARE  Box2 TYPE Box*  
     
  '--- Store the volume of a box here
  DECLARE volume TYPE  double    
  volume = 0.0
 
  '--- we have a simple way to do memory management
  '--- using low level memory
  '--- most GUI C++ code uses this type of syntax
  Box1 = new Box
  Box2 = new Box
 
  '--- box 1 set values
  Box1->height = 5.0
  Box1->length = 6.0
  Box1->width = 7.0

  '--- box 2 set values
  Box2->height = 10.0
  Box2->length = 12.0
  Box2->width = 13.0
 
  '--- volume of box 1 so you don't confuse pointers with  multiply
  volume = Box1->height * Box1->length * Box1->width
  PRINT "Volume of Box1 : " , volume

  '--- volume of box 2
  volume = Box2->height * Box2->length * Box2->width
  PRINT "Volume of Box2 : " , volume







[alexfish]

Hi Joe

Nice bacon example

CLASS can have functions to set values thoght would test this bit with your example


CLASS BOX: public Box
 public:
          BOX(float length,float width,float height){
set_size(length,width,height);
}
ENDCLASS

  DECLARE  mybox TYPE Box*  

 
mybox = new BOX(100,200,400)
PRINT mybox->width


ALL CODE

PRAGMA LDFLAGS -lfltk -L.
PRAGMA LDFLAGS -lbacon++
PRAGMA COMPILER g++
PRAGMA OPTIONS -Wno-write-strings -Wno-pointer-arith -Wno-permissive
OPTION PARSE FALSE



'--- Show the use of custom class.
'--- using BaCons new CLASS ENDCLASS commmand
'--- if you want to use C code printf
PRAGMA INCLUDE <stdio.h>
PRAGMA INCLUDE <string.h>
PRAGMA INCLUDE <stdlib.h>
'--- C++ style cout
PRAGMA INCLUDE <iostream>



CLASS Box
  public:
     double length;   // Length of a box
     double width;  // Breadth of a box
     double height;   // Height of a box

void set_size(float ln,float wd,float ht){
length=ln;
width=wd;
height=ht;


}

ENDCLASS

CLASS BOX: public Box
 public:
          BOX(float length,float width,float height){
set_size(length,width,height);
}
ENDCLASS

  DECLARE  mybox TYPE Box*  

 
mybox = new BOX(100,200,400)
PRINT mybox->width

  '--- Declare Box1 of type Box
  '--- Declare Box2 of type Box
  DECLARE  Box1 TYPE Box*  
  DECLARE  Box2 TYPE Box*  
     
  '--- Store the volume of a box here
  DECLARE volume TYPE  double    
  volume = 0.0
 
  '--- we have a simple way to do memory management
  '--- using low level memory
  '--- most GUI C++ code uses this type of syntax
  Box1 = new Box
  Box2 = new Box
 
  '--- box 1 set values
  Box1->height = 5.0
  Box1->length = 6.0
  Box1->width = 7.0

  '--- box 2 set values
  Box2->height = 10.0
  Box2->length = 12.0
  Box2->width = 13.0
 
  '--- volume of box 1 so you don't confuse pointers with  multiply
  volume = Box1->height * Box1->length * Box1->width
  PRINT "Volume of Box1 : " , volume

  '--- volume of box 2
  volume = Box2->height * Box2->length * Box2->width
  PRINT "Volume of Box2 : " , volume

all code

Added ; in c++ it is normal to free the bits as in delete :: a bit like DELETE WIDGET in gtk

IE

delete(mybox)

BR
Alex

[bigbass]

Thanks Alex
For that demo
Very useful

I will add one more example
With a function

Just to be complete
For most examples we will port
That should be enough to
get the idea of the CLASS
Command

Joe

[bigbass]

Hey Alex

Updated again
this covers a lot
showing many ways to get, set in bacon
make and call functions and subs too
and call functions in the class
and make functions in the class

mirror the class in memory
and rename it
this should cover about 80%
of the things we will need to do with the class

BaCon has come a long way in 10 years!
the bacon compiler can handle this now
that is really amazing
which means a new door has opened
and new improvements to come




PRAGMA LDFLAGS -lbacon++
PRAGMA COMPILER g++
PRAGMA OPTIONS -Wno-write-strings -Wno-pointer-arith -Wno-permissive
OPTION PARSE FALSE



'--- Show the use of custom class.
'--- using BaCons new CLASS ENDCLASS commmand
'--- if you want to use C code printf
PRAGMA INCLUDE <stdio.h>
PRAGMA INCLUDE <string.h>
PRAGMA INCLUDE <stdlib.h>
'--- C++ style cout
PRAGMA INCLUDE <iostream>


CLASS Box
  public:
     double length;        // Length of a box
     double width;        // Width of a box
     double height;       // Height of a box

     double len;
     double wid;
     double hei;
     // Member functions declaration
     
     double volume = len * wid *hei;
     
     // keep the ugly in the class out of the bacon area
     void BOX(double length,double width,double height){
     std::cout << "length width height from class  = " <<" " <<length
      <<" "<< width <<" " <<height << std::endl << std::endl;
      }
     
     double getVolume(void);
     void setLength( double len );
     void setWidth( double wid );
     void setHeight( double hei );
     
     //simple function without needing a callback  
     void display(){
     std::cout << "volume from class len * wid *hei = " << volume
     << std::endl << std::endl;
     }

ENDCLASS

'--- official way
'--- we get stuck here saying this function is comming out of the class
'--- by prefixing the Box::  
'--- a function out of the Box class is being used  yuck but it works
'--- If you can't change the class and define a function there this is
'--- what you have to do

SUB Box::setLength( double len )
  PRINT
  PRINT "SUB setLength() = " ,len
  length = len
  PRINT
END SUB




SUB Box::setWidth( double wid )
  PRINT
  PRINT "SUB setWidth() = " ,wid
  width = wid
  PRINT
END SUB




SUB Box::setHeight( double hei )
  PRINT
  PRINT "SUB setHeight() = " ,hei
  height = hei
  PRINT
END SUB


' I placed this in the class and used cout
'SUB Box::BOX( double length , double width , double height )
 ' PRINT "SUB BOX()"
  'PRINT length ," ", width ," ",  height
'END SUB

'--- function outside of the class syntax
FUNCTION Box::getVolume() TYPE double
  PRINT "Box::getVolume() = " , length * width *  height
  PRINT "when  length * width *  height values are "
  PRINT "      ", length ,"        ", width ,"        ",  height
  PRINT
  RETURN length * width *  height
END FUNCTION



'--- the simplified way
'--- will cheat and do the same thing with less syntax demand
'--- this is now my local getVolume2 SUB

SUB getVolume2()
  '--- we can set the volume like this
  rabbit->volume = rabbit->len * rabbit->wid * rabbit->hei
 
  PRINT "SUB getVolume2()  simpified way  volume = " ,rabbit->volume
  PRINT "when len * wid * hei have values of " ,rabbit->len ," ",rabbit->wid," ",rabbit->hei
  PRINT
END SUB
 
 
  '---===================================================================
 
  '--- we will pull a "magic rabbit" out of the box
  '--- and the crowd was amazed... even though everyone
  '--- knows no magic was used they ask the question
  '--- where did the rabbit come from ?

 
 
  '--- we gave it a nick name "rabbit" and mirrored the class in memory
  '--- the main reason to use classes in C++ we can recycle them

 
  '--- will use arrow operator syntax
  '--- we store a new chunk of memory
  '--- that copies what was declared in the official class
  '--- this makes for an easy way make new class names
  '--- without having to tediously repeat all the steps again
  '--- to make a class  
   
   DECLARE rabbit TYPE Box*
 
   
 
 
  '--- even though Box is a class we suffix  () like a function/subroutine
  '--- now we can simplify the callbacks to the class
   rabbit  = new Box()
 
   rabbit->length=100
   rabbit->width=200
   rabbit->height=300
   rabbit->len=4
   rabbit->wid=5
   rabbit->hei=6
   CALL getVolume2()
   PRINT "Get the width using the magic rabbit class : ", rabbit->width
   

  '--- this sets L W H in the class
  rabbit->BOX(100,200,400)
 
   
  '--- printing the values from inside the class
'--- we call a function in the class directly this is the callback
  '--- notice no need for the prefix Box::
rabbit->display()
 
  '--- set values then print from  bacon's SUB
  '--- c++ short way for the callback
  rabbit->setLength(8)
  rabbit->setWidth(9)
  rabbit->setHeight(10)
 
  '--- get print from bacon's FUNCTION
  '--- c++ short way for the callback
  rabbit->getVolume()
  '---===================================================================
 




terminal output

SUB getVolume2()  simpified way  volume = 120
when len * wid * hei have values of 4 5 6

Get the width using the magic rabbit class : 200
length width height from class  =  100 200 400

volume from class len * wid *hei = 120


SUB setLength() = 8


SUB setWidth() = 9


SUB setHeight() = 10

Box::getVolume() = 720
when  length * width *  height values are
     8        9        10


[bigbass]

Hey Guys


I wrote a custom widget class in c++

then all we need in bacon is the code below
to get the widget to compile
callbacks included too



PRAGMA LDFLAGS -lfltk -L.
PRAGMA LDFLAGS -lbacon++
PRAGMA COMPILER g++
PRAGMA OPTIONS -Wno-write-strings -Wno-pointer-arith -Wno-permissive
OPTION PARSE FALSE

'--- our custom class code all in one place
PRAGMA INCLUDE  foo2-include.h

'=========================================
'--- the rabbit part is a little joke
'--- we pull a magic rabbit out of a box
'--- and keep the class out of the bacon users view
'--- to have the shortest code possible
'=========================================

DECLARE rabbit TYPE Foo*
 rabbit = new Foo(0,0,400,200, "Hello Class Program")
Fl::run()


hello-class.tar.gz (1005 B)


Joe