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Object Oriented Liberty BASIC?

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Topic: Object Oriented Liberty BASIC? (Read 3292 times)

Richard Russell
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Object Oriented Liberty BASIC?
« Thread started on: Jun 8^th, 2014, 09:39am »

It's been suggested that it could be useful to add some simple OO (Object Oriented) features to LBB. That's certainly something I would be prepared to consider, but I'm not sure what the take-up would be. The impression I get is that a lot of LB programmers are quite 'old school' - too often I see programs that still use GOSUB! - and might find OO programming rather 'alien'.

If I were to go down that route I would expect to add the following keywords initially: CLASS, METHOD, NEW (or NEWOBJECT), DISCARD, INHERIT. They would support the fundamental operations necessary to create and manipulate objects. Note that it almost certainly wouldn't be practical to implement automatic object destruction when dropping out of 'scope'.

I would appreciate some feedback on this. Would you actually use such a feature if it was added?

Richard.

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lancegary
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Re: Object Oriented Liberty BASIC?
« Reply #1 on: Jun 8^th, 2014, 10:17pm »

Sounds a great idea though I would have to learn how to use them.

Thanks for the recent update as well.

Lance

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Richard Russell
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Re: Object Oriented Liberty BASIC?
« Reply #2 on: Jun 15^th, 2014, 8:30pm »

The conventional syntax for accessing an object method or field (member variable) would be to use a dot, such as object.method() or object.field, but the fact that a dot is a valid character in an LB identifier complicates things.

LB resolves the ambiguity in respect of structure members by adding the .struct suffix, and in principle it would be possible to adopt a similar syntax such as .object, but personally I think this is ugly.

So I am currently thinking that an OOP extension for LB could instead use the scope resolution operator ::, for example object::method() or object::field. In languages which use both the dot and :: notations there is a subtle difference in their meaning, but I am hoping that would only worry purists!

What do people think?

Richard.

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lancegary
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Re: Object Oriented Liberty BASIC?
« Reply #3 on: Jun 17^th, 2014, 2:12pm »

on Jun 15^th, 2014, 8:30pm, Richard Russell wrote:

I don't know enough to comment intelligently. The double colon is used in Fortran, I think. The subtle difference escapes me, however. They say beautiful aircraft fly well and mathematicians believe that all good maths is elegant or beautiful. So if the notation system seems elegant to you I'm sure it will be a pleasure for us to use.

Lance

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Richard Russell
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Re: Object Oriented Liberty BASIC?
« Reply #4 on: Jun 22^nd, 2014, 7:38pm »

The lack of feedback possibly indicates that people can't see the benefit in Object Oriented extensions to LBB. Here's an illustration (adapted from a Visual BASIC example) of how OOP features can be used simply to provide data structures which are otherwise not available in LB; in this case there are no 'methods' (subs or functions) in the classes:

Code:

    Dim person(10) As Person
    person(9)::Name$(1) = "John"
    person(9)::Name$(2) = "Smith"
    person(9)::address1::Street$(1) = "10"
    person(9)::address1::Street$(2) = "Royal Avenue"
    person(9)::address1::City$ = "Beverly Hills"
    person(9)::address1::Zip$  = "90210"

    Print person(9)::Name$(1); " ";
    Print person(9)::Name$(2)
    Print person(9)::address1::Street$(1); " ";
    Print person(9)::address1::Street$(2)
    Print person(9)::address1::Zip$
    Discard person()
    End

Class Person
    Dim Name$(2), address1 As Address
End Class

Class Address
    Dim Street$(3), City$, Zip$
End Class

Richard.

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Sean
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Re: Object Oriented Liberty BASIC?
« Reply #5 on: Jun 23^rd, 2014, 10:39am »

I would love to have OOPS, but we (the lb'ers) were kept waiting and are still waiting rolleyes

I think we have moved on. Does BBC basic support OOPS? I have moved on to AutoIt and Lazarus myself.

« Last Edit: Jun 23^rd, 2014, 10:40am by Sean »

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Richard Russell
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Re: Object Oriented Liberty BASIC?
« Reply #6 on: Jun 24^th, 2014, 1:38pm »

on Jun 23^rd, 2014, 10:39am, Sean wrote:

I would love to have OOPS, but we (the lb'ers) were kept waiting and are still waiting rolleyes

I think we have moved on. Does BBC basic support OOPS? I have moved on to AutoIt and Lazarus myself.

I see. If you feel like that, why did you join this forum?

Richard.

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Sean
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Re: Object Oriented Liberty BASIC?
« Reply #7 on: Jun 24^th, 2014, 2:34pm »

To praise your work. LBB definitely is going into my toolkit.

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bluatigro
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Re: Object Oriented Liberty BASIC?
« Reply #8 on: Jan 20^th, 2015, 09:06am »

i wood like it when
objects can be stored sepredly
in a *.bas

and can be added whit a 'import'
or 'include' comand

and i like to have operator overloading

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Richard Russell
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Re: Object Oriented Liberty BASIC?
« Reply #9 on: Jan 20^th, 2015, 09:17am »

on Jan 20^th, 2015, 09:06am, bluatigro wrote:

and can be added whit a 'import' or 'include' command

LBB has an 'include command. It works in a similar fashion to LB Workshop's include command, except that in LBW the included code is appended to the program, whereas in LBB it is inserted where the include statement is:

http://www.lbbooster.com/lbb.html#directives

The command is only recognised if it starts in the first column; preceding whitespace is not accepted. Also, for compatibility with LBW, 'include is ignored if it is at the very start of the program:

Code:

'ensure include is not the first line
'include mylib.bas

Edit:
Quote:

and i like to have operator overloading

Isn't 'operator overloading' useful only if the language has user-defined data types? Liberty BASIC doesn't (it has just numbers and strings).

Effectively there is already operator overloading to the extent that the + operator means different things for numbers and strings. Also, in LBB, some operators work on complete arrays:

Code:

    a() = b() + c()

Richard.

« Last Edit: Jan 20^th, 2015, 1:06pm by Richard Russell »

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bluatigro
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Re: Object Oriented Liberty BASIC?
« Reply #10 on: Jan 20^th, 2015, 11:11am »

'include error ?
or wat else do i wrong ?
_math.bas Code:

''bluatigro 20 jan 2015 :
''_math.bas
global pi , golden.ratio
pi = atn( 1 ) * 4
golden.ratio = ( sqr( 5 ) - 1 ) / 2
global true , false
true = not( false )
end
function rad( deg )
  rad = deg * pi / 180
end function

_color.bas Code:

'include _math.bas
''bluatigro 20 jan 2015 : 
''_color.bas
global black$ , red$ , green$ , yellow$
global blue$ , magenta$ , cyan$ , white$
global gray$ , pink$ , purple$ , orange$
black$   = rgb$( 000 , 000 , 000 )
red$     = rgb$( 255 , 000 , 000 ) 
green$   = rgb$( 000 , 255 , 000 ) 
yellow$  = rgb$( 255 , 255 , 000 ) 
blue$    = rgb$( 000 , 000 , 255 ) 
magenta$ = rgb$( 255 , 000 , 255 ) 
cyan$    = rgb$( 000 , 255 , 255 ) 
white$   = rgb$( 255 , 255 , 255 ) 
gray$    = rgb$( 127 , 127 , 127 ) 
pink$    = rgb$( 255 , 127 , 127 ) 
purple$  = rgb$( 127 , 000 , 127 ) 
orange$  = rgb$( 255 , 127 , 000 ) 
end
function rgb$( r , g , b )
  r = r and 255
  g = g and 255
  b = b and 255
  rgb$ = str$( r ); " " ; g * 256 ; " " ; b * 256 ^ 2
end function
function red( clr$ )
  red = val( word$( clr$ , 1 ) ) 
end function
function green( clr )
  green = val( word$( clr$ , 2 ) )
end function
function blue( clr$ )
  blue = val( word$( clr$ , 3 ) ) 
end function
function klmix$( kl1$ , f , kl2$ )
  r1 = red( kl1$ )
  g1 = green( kl1$ )  
  b1 = blue( kl1$ )  
  r2 = red( kl2$ )
  g2 = green( kl2$ )
  b2 = blue( kl2$ )
  r = r1 + f * ( r2 - r1 )
  g = g1 + f * ( g2 - g1 )
  b = b1 + f * ( b2 - b1 )  
  klmix$ = rgb$( r , g , b )
end function
function rainbow$( deg )
  rainbow$ = rgb$( sin( rad( deg ) ) * 127 + 128 _
                 , sin( rad( deg + 120 ) ) * 127 + 128 _
                 , sin( rad( deg - 120 ) ) * 127 + 128 )
end function

_sphere.bas Code:

'include _color.bas
''bluatigro 20 jan 1015
''_sphere.bas
WindowWidth = DisplayWitdh
WindowHeight = DisplayHeight
global winx , winy
winx = WindowWidth
winy = WindowHeight
global height
sub sphere h$ , x , y , z , d , clr$
  if abs( height - y ) < d then
    dd = sqr( d ^ 2 - ( height - y ) ^ 2 + .001 ) * 2
    kl$ = mix$( clr$ , .5 - ( height - y ) / d / 2 , black$ )
    #h$ "goto " ; x + winx / 2 ;" "; winy / 2 - height - z / 4 
    #h$ "backcolor " ; kl$
    #h$ "color" ; kl$
    #h$ "down"
    #h$ "ellipsefilled "; dd ;" "; dd / 4 
    #h$ "up"
  end if
end sub

main Code:

'include "_sphere.bas"
nomainwin
open "sphere-test" for graphics as #m
  #m "trapclose [quit]"
  for height = 0-winy/2 to winy/2
    call sphere #m , 0 , 0 , 0 , 50 , red$
  next height
wait
[quit]
  close #m
end

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Richard Russell
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Re: Object Oriented Liberty BASIC?
« Reply #11 on: Jan 20^th, 2015, 11:24am »

on Jan 20^th, 2015, 11:11am, bluatigro wrote:

or wat else do i wrong ?

Nothing "wrong" exactly, but you are hoping that 'include can be 'nested', i.e. that one included file can include another file, etc. Unfortunately it doesn't work like that in LBB, you can only use 'include in your 'main program':

Code:

nomainwin
open "sphere-test" for graphics as #m
  #m "trapclose [quit]"
  for height = 0-winy/2 to winy/2
    call sphere #m , 0 , 0 , 0 , 50 , red$
  next height
wait
[quit]
  close #m
end
'include _sphere.bas
'include _math.bas
'include _color.bas

As far as I'm aware LB Workshop's include has the same limitation.

Richard

« Last Edit: Jan 20^th, 2015, 1:01pm by Richard Russell »

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bluatigro
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Re: Object Oriented Liberty BASIC?
« Reply #12 on: Jan 20^th, 2015, 2:06pm »

i tryed this Code:

nomainwin
open "" for graphics as #m
  #m "trapclose [quit]"
  #m "fill black"
  for height = 0-winy/2 to winy/2
    call sphere 0 , 0 , 0 , 50 , red$
  next height
wait
[quit]
  close #m
end
'include _math.bas
'include _color.bas
'include _sphere.bas

Code:

''bluatigro 20 jan 1015
''_sphere.bas

  WindowWidth = DisplayWitdh
  WindowHeight = DisplayHeight
  global winx , winy
  winx = WindowWidth
  winy = WindowHeight
  global height

sub sphere x , y , z , d , clr$
  if abs( height - y ) < d then
    dd = sqr( d ^ 2 - ( height - y ) ^ 2 + .001 ) * 2
    kl$ = mix$( clr$ , .5 - ( height - y ) / d / 2 , black$ )
    #m "goto " ; x + winx / 2 ;" "; winy / 2 - height - z / 4 
    #m "backcolor " ; kl$
    #m "color" ; kl$
    #m "down"
    #m "ellipsefilled "; dd ;" "; dd / 4 
    #m "up"
  end if
end sub

_math.bas and _color.bas are not changed

error :
- where is my red sphere
- the window isnt fulscreen

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Richard Russell
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Re: Object Oriented Liberty BASIC?
« Reply #13 on: Jan 20^th, 2015, 4:42pm »

on Jan 20^th, 2015, 2:06pm, bluatigro wrote:

- where is my red sphere
- the window isnt fulscreen

I think your problem is that the code is now in the wrong sequence. Your 'included' file _sphere.bas contains both initialisation code which must come before the 'open for graphics' (e.g. setting WindowWidth and WindowHeight) and code which must come after the open statement (e.g. sub sphere). That can't work!

You either need to transfer the initialisation code into the 'main program', or you need to split your included file into two parts (e.g. _sphereinit.bas and _spheresub.bas) so you can include them in different places:

Code:

nomainwin
'include _sphereinit.bas
open "" for graphics as #m
  #m "trapclose [quit]"
  #m "fill black"
  for height = 0-winy/2 to winy/2
    call sphere 0 , 0 , 0 , 50 , red$
  next height
wait
[quit]
  close #m
end
'include _spheresub.bas

There's nothing 'magic' about 'include: the resulting 'merged' program must follow all the usual rules governing the order in which things are declared.

Richard.

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bluatigro
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Re: Object Oriented Liberty BASIC?
« Reply #14 on: Jan 23^rd, 2015, 11:30am »

update :
- all global's are now in *_init.bas

error :
- same errors

Code:

'include _fullscreen_init.bas
'include _math_init.bas
'include _color_init.bas
'include _sphere_init.bas
nomainwin
open "" for graphics as #m
  #m "trapclose [quit]"
  #m "fill black"
  for height = 0-winy/2 to winy/2
    call sphere 0 , 0 , 0 , 50 , red$
  next height
wait
[quit]
  close #m
end
'include _math.bas
'include _color.bas
'include _sphere.bas

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