     Subject: GFA Tutorial, The Editor
          By: James Collett (Professor)
 A Member Of: VIRTUAL INFINITY
       Email: s6005146@oxpoly.ac.uk (or s6005146@brookes.ac.uk)
     Address: Room N4, L.S.C.Collage, Wheatley, Oxford, OX9 1HX
 Mono accnt.: bcc


    Just  before we delve in,  a few shorts about the GFA  Basic  editor, 
 which is different depending on whether you have version two or  version 
 three  of the language.   The editor is fairly straight-forward  and  is 
 basically a specialised word processor or text editor for the language.
    When you first load the language you will find a blank screen  (where 
 you  enter  your source) and the menu at the top.   If you  are  running 
 version  two then the menu should span from Load/Save to  Run/Test.   If 
 you  are running version three then this should be your basic menu  with 
 an Atari symbol on the far left and a clock of the far right.


 GFA 2 And GFA 3 Basic Menu
 ==========================
    Load  & Save should speak for themselves,  they load & save in  GFA`s 
 unique  file structure or format,  sometimes called a tokenised  format. 
 This is not only unique to GFA, but also unique to different versions of 
 GFA.
    SaveA & Merge also load and save but in a standard ASCII format which 
 can  be loaded into a word processor,  another version of GFA  and  even 
 some other versions of Basic.   You will Merge sources off this tutorial 
 instead  of  loading  for that very reason,  so  this  tutorial  can  be 
 compatible with various versions of GFA.
    Merge is also used to append or merge two sources together.  When you 
 Load  the previous contents of the memory are wiped!   If you   wish  to 
 append two sources then Load or Merge the first,  move the cursor to the 
 correct position and Merge the second - just like a word processor.
    Llist prints the entire source currently in memory, assuming you have 
 a printer connected and on line.
    The  Block facility allows you to Copy,  Move and Delete sections  of 
 the  source;  it  also  allows you to Write (SaveA)  and  Llist  (print) 
 sections  of the program.   Before you can use it you must mark  out  or 
 high-light the block.
    Replace and Find allow you to either search for or search & replace a 
 particular  string (piece of text) in the source.   Note that these  are 
 case-sensitive and in GFA 2 you can only search for entire lines, in GFA 
 3 you can search for sections of lines.
    The next pair of buttons are used for paging up and paging down; this 
 is very labour-saving if you have more that a couple of screens full  of 
 text!
    Insert or Overwrite works just like and word processor, note that GFA 
 defaults to Insert.   The button above this is not spare,  but only used 
 when on monochrome (high res).
    Direct and Flip are both explained later this month.   Finally Run is 
 used  to execute (interpret - discussed later) the source  currently  in 
 memory.


 GFA 3 Extras
 ============
    In GFA 3,  as well as this basic menu, there is also a clock and line 
 indicator to the far right.  You can also use the line indicator to jump 
 straight to a particular line of the source.
    To  the far left,  the Atari symbol displays a GEM menu which  allows 
 you  to run resident accessories among other things.   The  small  space 
 under the Atari symbol indicates whether caps lock is on or not.


 Direct Mode And Editor Mode
 ===========================
    Anything you type on the editor screen will not instantly be run  and 
 will  be  added  to the source.   It is often  useful  to  directly  run 
 something  without interfering with the rest of the program - may be  to 
 test it before adding it to the source.
    This  can  be  done by selecting Direct either from the  menu  or  by 
 hitting <escape>.   GFA should now display an "OK >" prompt at which you 
 can directly execute single lines (discussed this month).   To return to 
 the editor either type 'edit' or hit <escape>.


 GFA Editor Short-cuts
 =====================
    On  the editor mode,  as well as clicking on the menu buttons at  the 
 top  you can also use the function keys to select a bottom  line  button 
 and <shift> plus a function key to select a top line button.
    Also  in  GFA 3,  on the direct mode,  you can use  <cursor  up>  and 
 <cursor  down>  to re-call lines you have already typed  on  the  direct 
 mode.


 ---END---
