                              PD-Edit Users Guide

                          By Rosemary Robertson-Smith



      I  DISCLAIMER

          Copyright (c) 1989 Rosemary Robertson-Smith

          PD-Edit is Shareware.  You may distribute it freely, but to  use
          it  legally  after  a 10-day evaluation period you must send $15
          to:

              Rosemary Robertson-Smith
              Ramtrack Software
              72 Bowers St.
              Nashua NH 03060

              (603) 889-6521

          In return, you will receive the latest copy  of  PD-Edit  and  a
          registration  number entitling you to technical support from the
          author.  You will also  receive  the  next  update  free.   Your
          honesty  will  enable Ramtrack Software to continue distributing
          quality Shareware products.  All comments are welcome.

          Please include a brief  description  of  your  system  when  you
          register.

          PD-Edit v1.0



      II  INTRODUCTION

          PD-Edit  is  a  simple  screen  editor,  designed  for  use   by
          programmers  and  other  users  who  don't want to deal with the
          overhead of word processors.   It  is  command  key  driven  and
          avoids modes of operation whenever possible.



      III  GETTING STARTED

          PD-Edit  is  a  binary  program  designed  to  run   under   the
          BASIC.SYSTEM program or any other ProDOS system program that can
          start a BIN program.  Upon startup, it  immediately  requests  a
          file-name  to edit.  If no filename is entered, the program will
          exit.

          When running, you may type in characters just as you  would  any
          word  processor.  You are only limited by the memory limitations
          of the ProDOS operating system.

          The binary version of  PD-Edit  is  called  PDEDIT.BIN  and  the
          Aztec-C  Shell  version  is call PDEDIT.PRG.  You may rename the
          programs to the names of your choice.


    PD-Edit                                                     Page 2


      IV  COMMAND KEYS

          Command keys are editing commands that invoke  editor  features.
          The following describes each key:

              Left-Arrow

                  Move left one character.

              Right-Arrow

                  Move right one character.

              Up-Arrow

                  Move up one line.

              Down-Arrow

                  Move down one line.

              Delete

                  Delete previous character.

              Tab

                  Insert spaces to next tab  stop.   Tab  stops  are  user
                  adjustable, but default to 4 character intervals.

              Control-E

                  Toggle  edit  mode.   The  two  modes  are  insert   and
                  overstrike.  The current mode is always displayed in the
                  status line.

              Control-T

                  File statistics.  Displays the current line  number  and
                  total  number  of  lines,  including  the  start and end
                  markers.

              Control-Z

                  Clears buffer.

              Escape

                  Execute special command.  Special commands are:

                          READ [file-name]

                          WRITE [file-name]

                          EXIT

                          QUIT

                          TABS [Width from 1 to 32]


    PD-Edit                                                     Page 3


              Return

                  Start a new line.

              Open-Apple-Left

                  Move left one tab-width.

              Open-Apple-Right

                  Move right one tab-width.

              Open-Apple-Up

                  Move up 16 lines.

              Open-Apple-Down

                  Move down 16 lines.

              Open-Apple-Return

                  Move to beginning of next line.

              Open-Apple-A

                  Insert a special character.  It requests a ASCII code to
                  insert  at  the current position.  The special character
                  will be represented by the checkerboard character.

              Open-Apple-B

                  Move to bottom of buffer.

              Open-Apple-C

                  Cut  selected  area.   PD-Edit  attempts  to  write  the
                  selected  area  to the file /RAM/PASTE.EDIT; however, if
                  you do not have sufficient space in the /RAM  directory,
                  the file will be written to the current directory.  This
                  implies that the cut lines can be  repasted  in  another
                  editing session.

              Open-Apple-D

                  Delete current line.

              Open-Apple-E

                  Move to end of line.

              Open-Apple-F

                  Find text.  The search is case sensitive.

              Open-Apple-G

                  Goto a line number.   Line  numbering  begins  with  the
                  [Start of Buffer] marker.


    PD-Edit                                                     Page 4


              Open-Apple-I

                  Insert a new line after the current line.

              Open-Apple-K

                  Start selecting lines for cut.  Only whole lines may  be
                  cut and pasted.

              Open-Apple-L

                  Toggle macro mode.  When  macro  mode  is  started,  the
                  status  line  will  display  the  word LEARN.  Until the
                  Open-Apple-L command is pressed  again,  all  keystrokes
                  are recorded.

              Open-Apple-M

                  Execute the macro that was most recently recorded by the
                  Open-Apple-L command.

              Open-Apple-N

                  Find next occurance of search string  that  was  entered
                  using Open-Apple-F.

              Open-Apple-P

                  Paste previously cut lines.

              Open-Apple-R

                  Set a repeat count.  A repeat count will cause the  next
                  command to be repeated the specified number of times.

              Open-Apple-S

                  Substitute for text.  It will request  a  search  string
                  and  then  a replacement string.  You have the option of
                  replacing none,  the  high-lighted  characters,  or  all
                  occurances  of  the  search string.  You may type in any
                  printable or non-printable character for the search.

              Open-Apple-T

                  Move to the top of buffer.

              Open-Apple-U

                  Undelete a line.  Undelete only recalls the last deleted
                  line.  Two deletes in a row will only permit the undo of
                  the most recent delete.

              Open-Apple-W

                  Move the cursor forward to the first character after the
                  next   white-space.    If   there   are  no  white-space
                  characters on the line, the cursor will be placed at the
                  first non-white-space character in the next line.


    PD-Edit                                                     Page 5


              Open-Apple-X

                  Delete current character.

              Open-Apple-Z

                  Refresh screen, placing the current line near the middle
                  of the screen.



      V  REQUESTING MORE INFORMATION

          For certain commands, you will be prompted for more information.
          The  routine  that  requests  the  input  has the following edit
          features and restrictions:

               o  Control-Z will clear the current input buffer.

               o  Delete will erase the previous character.

               o  Escape will cancel the input and return to  the  editing
                  window.

               o  Cursor key movement is not supported.

               o  A beep will sound when you reach the maximum  number  of
                  characters   or   you   attempt  to  insert  an  invalid
                  character.

               o  To insert non-printing  characters  such  as  a  TAB  or
                  FORMFEED,  you  must  hold the Open-Apple key down while
                  pressing the desired key.

               o  If the input has a default value,  the  cursor  will  be
                  placed after the last character in the default.




      VI  EDITING TIPS

          If your line exceeds 80 characters,  an  exclamation  mark  will
          appear  at  the  end of the line.  This indicates that there are
          hidden characters.  You can still use all  the  cursor  movement
          and  search  commands;  however, while accessing characters past
          the 80th column in a line  will  keep  the  cursor  at  physical
          column 80.

          If you move the cursor down to a line that is  actually  shorter
          than  the  previous  line.  The cursor will not be placed at the
          end of the  line;  instead,  it  will  maintain  its  horizontal
          position.   If  you  do  not insert any characters, the original
          end-of-line will  not  change;  however,  if  you  do  insert  a
          character,  PD-Edit  will  fill  the  line with spaces until the
          end-of-line is at the current cursor position.

          Tabs insert spaces and not the ASCII tab character.  This  costs
          more memory; however, it makes your text files compatible across


    PD-Edit                                                     Page 6


          many platforms.



      VII  RUNNING PD-EDIT FROM THE BASIC SYSTEM PROGRAM

          The following EXEC  file  should  be  created  to  properly  run
          PD-Edit from Apple BASIC:

              BRUN EDIT -BASIC.SYSTEM

          The reason for reloading BASIC after running the PD-Edit is that
          some global information is overwritten by the editor.  This will
          prevent proper BASIC operation.



      VIII  EDITING AN APPLE BASIC PROGRAM

          To edit an Apple BASIC  program,  you  must  first  convert  the
          program  to  a  text  file by placing the following lines at the
          beginning of the BASIC program:

              1 PRINT CHR$(4);"OPEN PROGRAM.BAS"
              2 PRINT CHR$(4);"WRITE PROGRAM.BAS"
              3 LIST
              4 PRINT CHR$(4);"CLOSE PROGRAM.BAS"

          This will cause a listing of the current program to be placed in
          the file "PROGRAM.BAS", which can then be edited by PD-Edit.

          To convert the text program back to BASIC, issue  the  following
          command:

              EXEC PROGRAM.BAS




      IX  PROGRAM TAMPERING

          If you suspect program tampering, or you just want  to  reassure
          the  integrity  of  the editor code, there is a checksum program
          that can be run.  Execute the following procedure:

              1.  Get into Apple BASIC

              2.  BRUN CHECKSUM

              3.  It will then prompt you for the editor file  name.   You
                  must provide the complete ProDOS path.

              4.  The program will print out 3 numbers.

              5.  Call  the  author  and  request   a   program   checksum
                  validation.  You must provide the numbers printed out by
                  CHECKSUM and the PD-Editor version number.   The  author
                  will confirm whether the program has been modified by an
                  unauthorized user.


    PD-Edit                                                     Page 7


      X  TECHNICAL INFORMATION

          PD-Edit has approximately a 17,000 character limit on  the  size
          of  a  file.   If you attempt to load a file that is larger than
          this limit, PD-Edit will truncate it.  The 17,000 value may vary
          due  to  file attributes.  A line in a file requires 9 bytes for
          overhead, so the amount of memory available  to  the  editor  is
          directly  proportional  to  the  number of lines in the file and
          each line length.

          The maximum line size is 250 characters.

          The maximum file-name length is 64 characters.

          The maximum repeat-count is 5000.

          The maximum search/replace string is 32 characters.

          The maximum tab width is 32 spaces.

          The maximum length of the macro buffer is 255 characters.

          PD-Edit is written using the C language and 6502 assembler.

