Test 08-object-prototype-point.p

Source of programm

# 0bject oriented programming with prototypes: point class

sub make_point( x, y )

    return { 'x_pos' : x,
             
             'y_pos' : y,
             
             'move'  : sub ( dx, dy ) 
                            this . x_pos = this . x_pos + dx
                            this . y_pos = this . y_pos + dy

                            return this
                       end,

             'print' : sub ( )
#                           println( ~msg 'point x-pos: [ this . x_pos ]  y-pos: [ this . y_pos ] ' )
                            println( ~msg 'point x-pos: ' .. this . x_pos .. '  y-pos: ' ..  this . y_pos  )
                       end,

             'get_x' : sub ( )
                            return this . x_pos
                       end,

             'get_y' : sub ( )
                            return this . y_pos  
                       end
            }
end            


pt = make_point( ~x 10 ~y 10 )

pt . print ()

pt . move ( ~dx 1 ~dy -1 )

pt . print ()

println( ~msg 'point-accessors x = [ pt . get_x () ]  y = [ pt . get_y() ]' )

             

Standard output for 08-object-prototype-point.p

point x-pos: 10  y-pos: 10
point x-pos: 11  y-pos: 9
point-accessors x = 11  y = 9

Trace output for 08-object-prototype-point.p

032|... = make_point( ~x 10 ~y 10 )...
005| return { 'x_pos' : x:10 , 'y_pos' : y:10 , 'move' : sub (~dx , ~dy) , 'print' : sub () , 'get_x' : sub () , 'get_y' : sub () }
032|pt = make_point( ~x 10 ~y 10 ):{ 'move' : sub , 'get_y' : sub , 'x_pos' : -> 10, 'print' : sub , 'get_x' : sub , 'y_pos' : -> 10 }
034|pt{'print'}:sub (  )...
018| println( ~msg 'point x-pos: ' .. this{'x_pos'}:10 .. '  y-pos: ' .. this{'y_pos'}:10 )...
036|pt{'move'}:sub ( ~dx 1 ~dy  - 1 )...
010| this{'x_pos'}:11 = (this{'x_pos'}:10 + dx:1):11
011| this{'y_pos'}:9 = (this{'y_pos'}:10 + dy:-1):9
013| return this:{ 'move' : sub (~dx , ~dy), 'get_y' : sub (), 'x_pos' : -> 11, 'print' : sub (), 'get_x' : sub (), 'y_pos' : -> 9 }
036|pt{'move'}:sub ( ~dx 1 ~dy  - 1 ):-> { 'move' : sub , 'get_y' : sub , 'x_pos' : -> 11, 'print' : sub , 'get_x' : sub , 'y_pos' : -> 9 }
038|pt{'print'}:sub (  )...
018| println( ~msg 'point x-pos: ' .. this{'x_pos'}:11 .. '  y-pos: ' .. this{'y_pos'}:9 )...
040|println( ~msg 'point-accessors x = ' .. pt{'get_x'}:sub (  )...
022| return this{'x_pos'}:11
040|println( ~msg 'point-accessors x = ' .. pt{'get_x'}:sub (  ):-> 11 .. '  y = ' .. pt{'get_y'}:sub (  )...
026| return this{'y_pos'}:9
040|println( ~msg 'point-accessors x = ' .. pt{'get_x'}:sub (  ):-> 11 .. '  y = ' .. pt{'get_y'}:sub (  ):-> 9 .. '' )...