commands (RECORD) (WITH) unscrambled

[bigbass]

Well this is something I had to figure out because I used
some code to convert glade xml to bacon that I didn't write


in doing so I encountered the RECORD and WITH command
which looks a bit odd at first glance

I wondered if this has another way of seeing it

so here we go with a different example
after doing this test the result is RECORD
is a great BaCon tool




RECORD  myVector
   LOCAL x
   LOCAL y
END RECORD


WITH myVector
   .x = 1
   .y = 10
 
END WITH


PRINT "another ugly thing in C to convert is"
PRINT
PRINT "x = ", "myVector->x"
PRINT "y = ", "myVector->y"
PRINT
PRINT "the idea is but this syntax doesnt work this way in BACON"
PRINT
PRINT "x = ", "myVector[0].x"
PRINT "y = ", "myVector[0].y"

PRINT

PRINT "but in BaCon we use RECORD and WITH"
PRINT "using this syntax myVector.x"
PRINT
PRINT  "myVector->x " , "can be translated to"
PRINT  "myVector.x "
PRINT "the value is = " ,myVector.x

PRINT "========================"
PRINT
PRINT "lets do y now so everything is clear"
PRINT "using this syntax myVector.y"
PRINT
PRINT  "myVector->y ",  "can be translated to"
PRINT  "myVector.y "
PRINT "the value is = " ,myVector.y


PRINT
PRINT "lets add them together"
PRINT myVector.x + myVector.y



another ugly thing in C to convert is

x = myVector->x
y = myVector->y

the idea is but this syntax doesnt work this way in BACON

x = myVector[0].x
y = myVector[0].y

but in BaCon we use RECORD and WITH
using this syntax myVector.x

myVector->x can be translated to
myVector.x
the value is = 1
========================

lets do y now so everything is clear
using this syntax myVector.y

myVector->y can be translated to
myVector.y
the value is = 10

lets add them together
11

[bigbass]

Here is an example with FLOATING
*thanks vovchik for the FLOATING type



RECORD myVector
LOCAL x TYPE FLOATING
LOCAL y TYPE FLOATING
END RECORD


WITH myVector
.x = 1.5
.y = 10.2

END WITH


PRINT " the value is ",myVector.x
PRINT " the value is ",myVector.y
PRINT
PRINT "lets add them together"
PRINT myVector.x + myVector.y
PRINT

the value is 1.5
the value is 10.2

lets add them together
11.7

[bigbass]

Here is a reduced working snippet from a complex use of RECORD and WITH
taken from a glade to bacon converter example
(this may be helpful if you want to edit the code )



using the unmodified original code it isnt easy to follow exactly what is happening
so this is a cut down example once this is clear the code just replaces the search string
and the start and stop positions



'--- set up the RECORD
RECORD glade[1000]
LOCAL class$ TYPE STRING
LOCAL wtype TYPE NUMBER
END RECORD


'--- set up some variables
q$ = CHR$(34)
reccount = 0



'---manually added escape on the double quotes inside the string
txt$ = "<widget class=\"GtkVBox\" id=\"vbox2\">"

PRINT "This is txt$ "
PRINT txt$
PRINT


idx = INSTR(txt$, "class=")
IF idx > 0 THEN
startpos = idx + 7
endpos = INSTR(txt$, q$, idx + 8)
END IF



PRINT "look for GtkVBox"
PRINT "count all spaces and characters "
PRINT
PRINT "startpos = " , startpos
PRINT "endpos= " , endpos
PRINT

PRINT "place the GtkVBox using the WITH command"
PRINT "in glade[reccount].class$"


WITH glade[reccount]
.class$ = MID$(txt$, startpos, endpos - startpos)
END WITH


PRINT
PRINT "now print glade[reccount].class$"
PRINT glade[reccount].class$  

This is txt$
<widget class="GtkVBox" id="vbox2">

look for GtkVBox
count all spaces and characters

startpos = 16
endpos= 23

place the GtkVBox using the WITH command
in glade[reccount].class$

now print glade[reccount].class$
GtkVBox

[bigbass]

If we are going to use glade xml files the main part of the code is
getting the variables parsed

here in this example you can use a real glade file without having to pre escape the
double quotes

I changed idx for the word offset

change only this line to point to a glade file
gladefile$ ="/usr/share/BaCon/glade2bas.glade"


now "finally" editing original code will be easier

@ vovchik asked if I would add some callbacks
now I can consider that had to understand this part of the code first





'--- set up the RECORD
RECORD glade[1000]
LOCAL class$ TYPE STRING
LOCAL wtype TYPE NUMBER
END RECORD


'--- set up some variables
q$ = CHR$(34)    
reccount = 0


gladefile$ ="/usr/share/BaCon/glade2bas.glade"
OPEN gladefile$ FOR READING AS fh
WHILE NOT(ENDFILE(fh)) DO
READLN txt$ FROM fh
IF NOT(ENDFILE(fh)) THEN

offset = INSTR(txt$, "class=")
IF offset > 0 THEN
startpos = offset + 7
endpos = INSTR(txt$, q$, offset + 8)

PRINT "startpos = " , startpos
PRINT "endpos= " , endpos

WITH glade[reccount]
.class$ = MID$(txt$, startpos, endpos - startpos)
END WITH

PRINT
PRINT "now print glade[reccount].class$"
PRINT glade[reccount].class$  
PRINT
END IF
     END IF
WEND
CLOSE FILE fh



startpos = 18
endpos= 27

now print glade[reccount].class$
GtkWindow

startpos = 22
endpos= 29

now print glade[reccount].class$
GtkVBox

startpos = 26
endpos= 36

now print glade[reccount].class$
GtkMenuBar

startpos = 30
endpos= 41

now print glade[reccount].class$
GtkMenuItem

startpos = 34
endpos= 41

now print glade[reccount].class$
GtkMenu

startpos = 38
endpos= 54

now print glade[reccount].class$
GtkImageMenuItem

startpos = 38
endpos= 58

now print glade[reccount].class$
GtkSeparatorMenuItem

startpos = 38
endpos= 54

now print glade[reccount].class$
GtkImageMenuItem

startpos = 30
endpos= 41

now print glade[reccount].class$
GtkMenuItem

startpos = 34
endpos= 41

now print glade[reccount].class$
GtkMenu

startpos = 38
endpos= 49

now print glade[reccount].class$
GtkMenuItem

startpos = 26
endpos= 38

now print glade[reccount].class$
GtkHandleBox

startpos = 30
endpos= 40

now print glade[reccount].class$
GtkToolbar

startpos = 34
endpos= 47

now print glade[reccount].class$
GtkToolButton

startpos = 34
endpos= 54

now print glade[reccount].class$
GtkSeparatorToolItem

startpos = 34
endpos= 47

now print glade[reccount].class$
GtkToolButton

startpos = 34
endpos= 54

now print glade[reccount].class$
GtkSeparatorToolItem

startpos = 26
endpos= 35

now print glade[reccount].class$
GtkLayout

startpos = 30
endpos= 44

now print glade[reccount].class$
GtkCheckButton

startpos = 30
endpos= 44

now print glade[reccount].class$
GtkCheckButton

startpos = 30
endpos= 38

now print glade[reccount].class$
GtkLabel

startpos = 30
endpos= 38

now print glade[reccount].class$
GtkEntry

startpos = 30
endpos= 39

now print glade[reccount].class$
GtkButton

startpos = 34
endpos= 42

now print glade[reccount].class$
GtkImage

startpos = 26
endpos= 33

now print glade[reccount].class$
GtkHBox

startpos = 30
endpos= 38

now print glade[reccount].class$
GtkFrame

startpos = 34
endpos= 42

now print glade[reccount].class$
GtkLabel

startpos = 30
endpos= 42

now print glade[reccount].class$
GtkStatusbar

[bigbass]

This is just theory with some examples
C code and BaCon are not the same
we have to strip out the C code
and replace it with bacon code


This first example is to show how pointers work (in theory only)
when there is an int or a STRING
this is using the SIZEOF( ) command to get the
size of the type used

since a pointer isnt a value itself

this is just the idea I dont like to use pointers when converting code to bacon
and we can write better code in bacon without using pointers at all







GLOBAL   *button,  TYPE STRING
GLOBAL *align,  *vbox TYPE int

ptr = SIZEOF( *align )
PRINT ptr


v = SIZEOF(*vbox )
PRINT v


testptr = SIZEOF( *button)
PRINT testptr





This second example shows how to get the size of a RECORD
or getting the size of a struct in C when we convert it to bacon code




RECORD mystruct
LOCAL x
LOCAL y
LOCAL z
LOCAL a
LOCAL b
END RECORD


WITH mystruct
.x =1
.y = 50
.z = 100
.a =200
.b =700
END WITH



'---this one grows or shrinks
'---we can cheat and get the struct pointer size
'---the LOCAL sets 4  as the size

cheatptr = SIZEOF( mystruct)
PRINT cheatptr


the result is 20 that is 5x4=20
the size of 4 for each variable stored