BASIC
# AppBasic

to add an app, say !app to examples
open !AppBasic and copy !app to  ...!AppBasic.Resources.Examples
NOTE !app must be in AppBasic format


#   debugging BASIC - see TRACE using !Reporter


#   convert textfile to basic - or EVAL blanks
    StrongEd detokenises basic files when loading and tokenises them
    when saving. This gives rise to a problem when trying to get code
    in from a text file.

    1 -  Save as basic then change all "EVAL" to "" -  preserves indents
    or,
    2 -  remove all blanks before saving as basic.


#   BASIC docs soft
     - don't forget HELP in BASIC environment
     - ADFS::HardDisc5.$.DOCZ.!Manuals.Root.BASIC
     - ADFS::HardDisc5.$.DOCZ.!Manuals.Root.AppBasic
     - ADFS::HardDisc5.$.PROGRAMZ.BASIC.APPBASIC.AppBasic/pdf
     - ADFS::HardDisc5.$.DOCZ.ROadjust.manuals.HTML.INDEX/HTML
     - !Routines has helptext and eg program !MouseInfo
     - DRWimp ADFS::HardDisc5.$.DOCZ.!Manuals.Root.FuncProc
     - DRWimp ADFS::HardDisc5.$.PROGRAMZ.DRWIMP.HTMLManual.Contents/html
     - DRWimp ADFS::HardDisc5.$.PROGRAMZ.DRWIMP.Documents.!Fnc'n'Prc

     - BBC BASIC for Windows - see web site

#   BASIC docs paper
     - BASIC V Mike Williams book
     - BBC Microcomputer User Guide
     - Archimedes User Guide
     - DR Wimp's surgery

#   running a BASIC program in a task window 1

#   running a BASIC program in a task window 1
    easy -
    run !GraphTask
    drop basic program on iconbar icon

    to run another - menu on window
     >>Kill
     >>Reconnect
      drop basic program on window

#   running a BASIC program in a task window 2

   Create a text file with the code to be executed.
   Give it a Type of TaskExec  (&FD6).
   Double click it and it will run in a TaskWindow

   eg:-
     echo 
     basic
     10 a$ = "The time is "+ STR$(TIME)
     20 PRINT a$
     RUN
     PRINT "We are still in BASIC mode Until we QUIT"
     *echo note - the star is needed as we are in BASIC
     LIST
     QUIT




#   running a BASIC program in a task window 3

    "Ever wanted a BASIC program or stand-alone ABSOLUTE to open in a
    TaskWindow without all the messing about?
    !InAWindow
    , installed in Boot.Tasks, defines two new filetypes -
    TskBasic   and  TaskApp
    - that perform this miracle. You will probably want to alter Zap's
     Types
    file so &AA5 is loaded into Basic mode, and &AA6 is loaded into Code
    mode.

    Yes, these filetypes and the Boot.Tasks location were officially
    allocated." Nemo

    to use:- edit the BASIC program in SEd Basemode
    save with type "TskBasic" and double click to run
    (do not just change the type form BASIC to TskBasic)


#   Reading a system variable from BASIC

    eg this works
       DIM buffer%255
       var$ = "Obey$Dir"
       SYS"OS_ReadVarVal",var$,buffer%,255,0,3 TO ,,bytes%,type%
       buffer%?bytes%=13
       a$=$buffer%
       *report a$
    but read on...

    system variable set in the !Run:-  Set MaxNumberOfFonts 32
    want to read this value into a BASIC variable.

    first thing we need to do is to extract the value of the
    system variable   into a string that we can manipulate.
    PRM volume II, eventually found OS_ReadVarVal (SWI &23) on page 750.
    On entry,
     R0 points to the name of the system variable to be read,
     R1 points to a suitable buffer to store the string in,
     R2 is the maximum length of this buffer,
     R3 set to 0 to use first occurrance of the named system variable
     R4 set to 3 so that an expanded string is returned in the buffer.

    On exit, we have the value of the system variable in a string.

    The next task is to convert this string into a number using
    OS_ReadUnsigned  (SWI &21) on page 585. On entry,
     R0 set to 0 so base is 10 unless string indicates otherwise,
     R1 is the pointer to the string
    On exit:
     R2  contains the value of the system variable as an integer,

    In BASIC this can be achieved with 4 instructions:

    MaxBufferLength = 16
    DIM Bufferptr MaxBufferLength
    SYS "OS_ReadVarVal","MaxNumberOfFonts",Bufferptr, MaxBufferLength,0,3
    SYS "OS_ReadUnsigned",0,Bufferptr TO ,,value%

    To give a quick example of its use:
     'SetMaxNumber OfFonts 16' gives value% = 16
     'SetMaxNumber OfFonts &20' gives value% = 32

    This may be of use to programmers, as it allows constants to be set
    up in the !Run obey file and users can modify them to fit their
    requirements, without having to modify the program itself.
    John 'Lofty' Wallace.

#   write a system variable from basic and display OS level
     set Sys$level dummy
     basic
     100 REM
     120 ON ERROR PROC_error
     200 SYS "OS_Byte",0
     300 END
     500 DEFPROC_error
     520 LET oslevel$=REPORT$
     525 *report oslevel$
     530 PROC_setvar
     550 END
     590 ENDPROC
     700 DEFPROC_setvar
     710 syslev$="Sys$Level"
     720 SYS "OS_SetVarVal",syslev$,oslevel$,LEN(oslevel$),4
     730 REM
     740 REM
     790 ENDPROC
     RUN
     QUIT
     show Sys$level


#   run a star command from basic with a variable

    eg 1
    LET ip$ = "loopback"
    OSCLI ("ping -c1 " + ip$)


#   ascii hex and characters in BASIC
    delim$ = CHR$(9)


#   concatenation of strings - use +

© JR 2013