Edit User Manual
Program written by Rick McClain

I. Introduction

Edit was designed to function much like Digital Equipment Corporation's EDT
editor for the VAX computer. Edit was primarily written in IBM Pascal,
excepting screen, disk, and text buffer utilities, which were written in IBM
Macro Assembler. IBM Pascal proved to be an excellent language choice for
Edit. Edit executes fast and is memory efficient. The nearly 2000 lines of
source code in Edit resulted in a program size of only 19k. As a result, Edit
can be used in systems with as little as 48k of memory. The only other
requirements are at least one disk drive and an 80 column display (either
color or monochrome card).

Edit is compatible with BASIC (when saved with the A option), all of IBM's
compilers, and the IBM assembler. The format of the text files generated by
Edit is identical to the format generated by IBM's Edlin line editor.

The philosophy behind Edit is that an editing program should not impede the
thought processes of the programmer or writer who uses it. What you see on the
screen is your text. To add to it you position the cursor and type. To help
you locate a specific point in your text a search function is provided which
searches either forward or backward with equal speed for any search string you
type in. Multiple searches can be performed without retyping the string. To
move text around, a cut and paste function is provided. You select the text to
be cut by positioning the cursor and pressing a select key. Now when you move
the cursor, the selected text appears in reverse video. You don't need to
remember where you placed the select point, you are provided instant feedback.
Press the cut key and the selected text disappears. Move the cursor, press the
paste key and it reappears. Press the paste key again and a second copy
appears. To aid you in formatting your program or text, Edit provides user
definable tabs as well as default settings useful for Pascal or Fortran
programming.

Editing in Edit takes place on text which resides in the memory text buffer.
Edit adapts the size of the text buffer to use all available memory in any
system on which it is run. Edit works best when files fit within the text
buffer, because one can quickly move about the whole file. However, Edit does
have features, similar to IBM's Edlin editor, for dealing with large files.
When a file is too large to fit in memory, only part of it is read into the
text buffer. After the text in memory is edited, some of the text buffer is
written out to disk, making room for more of the input file.

Edit allows you to move about the text buffer very quickly. Moving the cursor
in every direction proceeds at the speed of the keyboard auto repeat. This
means that you can scroll through the text buffer at a speed of about 10
lines/second. You can page through the text buffer at 50 lines/second. Moving
along a line is aided by keys to move the cursor from word to word. Moving to
the top or bottom of the text buffer is instantaneous.













II. Getting started

Using Edit requires the monochrome display card, a disk drive and at least 48k
of memory. To run Edit, insert the disk in either (or the only) drive. Then
type (see footnote)

[d:]edit

The drive designator is necessary only if edit was not inserted in the default
drive. After Edit is loaded and the copyright information is displayed, Edit
will issue an asterisk (*) as a prompt. If you wish, you can now remove the
Edit disk, because all of Edit is now loaded into memory, which allows you to
now insert your work disks into the drive.

Edit starts up in the command mode (identified by the asterisk * prompt). At
this point you may type in any of the commands in the next section to read
files from disk and put them in the text buffer. Or you may prefer to switch
to screen mode immediately (using the S command) and begin typing in new text.
Command mode and screen mode are the only modes, and you can switch back and
forth between them by typing the S command when in command mode and CTRL-Z
(press CTRL key and then press Z key) when in screen mode.

Another way to run Edit allows you to specify the filename of an already
existing file in the command line. From DOS type

[d:]edit [d:]filename.ext

Edit will be loaded and then immediately read the file into the text buffer.
Specifying the filename in the command line is equivalent to using the other
format, and then immediately entering an R (read) command.

The next section will describe the Edit commands that are executed while in
the command mode (in response to the * prompt). Section IV will describe
operations when in the screen mode, which is entered using the S command.

















Footnote: Brackets [] are used to denote optional items, and should not be
typed in. The drive specifier, d, should be replaced with the actual drive
specifier in which you have placed Edit.




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III. Command Descriptions

When Edit is in the command mode, it issues an asterisk (*) as a prompt. At
this point any of the commands to be described can be entered. Commands are a
single character (H,S,C,R,I,T,W,E,Q). It makes no difference to Edit whether
the commands are upper or lower case. Some of the commands require extra
information, which should always be typed immediately after the command
character without any spaces. Example: RFILE.TXT will cause the file,
FILE.TXT, to be read from the default disk drive and placed into the text
buffer. The command is not executed until you hit return, so that the
backspace key can be used to delete mistakes.

In the command descriptions below, file names are denoted [d:]filename.ext.
Any valid DOS file name can be used. If no drive is specified then the default
drive is assummed.

_H - _H_e_l_p

Format: *H

In response to the H command, Edit prints out a list of the available commands
and a few words to describe each of them. The help command is only intended to
be a memory jogger, not a replacement for reading this user manual (so keep on
reading).

_S - _S_c_r_e_e_n _m_o_d_e

Format: *S

Entering the command S causes Edit to switch to the screen mode, which is the
mode for entering and modifying text. While in the screen mode, what you type
is entered into the text buffer to the left of the cursor, and what you see on
the screen is the format of the actual text file.

The special purpose keys and functions for moving about and modifying text,
which are available while in screen mode, will be described in the next
section.

The screen mode is exited by typing CTRL-Z (by pressing CTRL key and then
pressing Z key).

_C - _C_r_e_a_t_e _f_i_l_e

Format: *C[d:]filename.ext

In response to the C command, Edit creates the file specified and copies to it
the contents of the text buffer. If the file existed prior to the command then
the old contents are replaced. The C command is the normal method for
initially creating a file. Note that the contents of the text buffer is not
modified by this command.








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_R - _R_e_a_d _f_i_l_e

Format: *R[d:]filename.ext or *R

The R command is used to open and read into the text buffer a file that
already exists. The file is appended to the end of any text that is already in
the text buffer. If the text buffer becomes 90% filled then reading is
suspended and the file is left open. Edit will inform you if this happens.
While the file is still open the disk should not be removed from the drive. In
order to read in the rest of the file, memory must be freed up by either using
the W command described below, or deleting text. When memory becomes available
you can continue to read from the still open file by using the second format
(*R) for the read command.

_I - _I_n_s_e_r_t _f_i_l_e

Format: *I[d:]filename.ext

The I command is used to insert the contents of the specified file into the
text buffer. The file is inserted into the text buffer to the left of the
cursor position. The I command cannot be used if a file is still open as a
result of a previous R command. Only as much of the file as will fit into the
text buffer will be read. The file is closed at the conclusion of reading.
Thus insert should only be used if you are reasonably sure that the whole file
can be read in.

_T - _T_a_b_s

Format: *T or *TP or *TF or *TN

The T command is used to set tabs. Typing T without a modifier results in Edit
prompting you to input the tab settings. First Edit prints a line of column
numbers. Then you type in a line of spaces and t's. Tabs are set in the
columns in which you place a t. When you are in the screen mode, pressing the
tab key causes spaces to be inserted into the text until the cursor is in a
tab column.

The TP command sets tabs to the Pascal default settings (every third column
starting with column four) and the TF command set tabs to the Fortran default
settings (every third column starting with column seven).

The TN command turns off the editor tab function. Typing the tab key now
causes the ASCII tab character to actually be inserted into the text buffer.
The tab character is interpreted in the generation of the screen display in
the same manner as DOS interprets tab characters (tab setting in every eighth
column starting with column nine).

Edit starts up with tabs turned off, thus there is no reason to use the TN
command, unless one of the other tab commands is executed first.









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_W - _W_r_i_t_e _f_i_l_e

Format: *W[d:]filename.ext or *W

The W command causes the file specified to be created and writes out the text
buffer up to but not including the cursor position. If the file existed prior
to the command then the contents are replaced. The text that is written out is
then deleted from the text buffer, freeing up memory for the reading of more
text. The file created remains open for the rest of the editing session. The
disk must remain in the drive for the duration of the editing session. To
write more text to the file, position the cursor (while in the screen mode)
and use the second form of the command (W with no filename).

The W command is intended to be used in conjuntion with the R command when
working with files which are too large to fit into memory. The R command is
used to read in some text, which can be edited. Then the W command is used to
write out some text making room for more. For smaller files, you are advised
to use the C and E commands for text file creation and replacement.

_E - _E_x_i_t

Format: *E

The E command writes out the text buffer to a disk file and terminates the
editing session. The file written to is determined as follows:

If a write file is currently open (due to a previous W command), then the
entire text buffer is written out to that file. Then, if a read file is still
open (due to a previous R command), the rest of the read file is copied to the
write file. In other words, the E command is the normal method for terminating
an edit of a large file.

If no write file is open, then the first file that was read, whether given in
the initial Edit command line or given in an R command, is rewritten with the
current contents of the text buffer. Thus, the E command is the normal method
for terminating an edit of a file be it large or small.

If no file was ever read, then the E command is equivalent to a Q (abort)
command. Edit will ask you to verify this because it results in the loss of
any text that you have generated.

_Q - _Q_u_i_t

Format: *Q

The Q command causes Edit to abort the editing session. Any open files are
closed, but the contents of the text buffer is not saved. Edit will ask you to
verify this command.










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IV. Screen mode

To switch to the screen mode, type in the S command while in the command mode
(in response to the * prompt).

To leave the screen mode, type CTRL-Z (by pressing CTRL key and then pressing
Z key). Edit will return to command mode and issue a prompt (*).

When in the screen mode, the top 24 lines of the screen display the contents
of 24 lines of text from the text buffer. The bottom (25th) line is used to
display information and to input search strings. If a line has more than 80
characters, then the characters beyond the 80th character do not appear on the
screen. The number on the far right of the bottom line tells you how many
bytes of text buffer you have left before it is filled up. This number is
constantly updated.

Should you accidently try to overfill the text buffer, Edit will immediately
transfer to command mode and inform you that you need to make room in the text
buffer to continue. No text will be lost.

While in the screen mode, you type in text and it is inserted into the text
buffer to the left of the cursor position. When you hit return a new line is
created and the text that was to the right of the cursor is moved down to the
new line. Return functions exactly like any other character except that you
don't see a return character, instead, return causes text to begin on the next
line. Return can be imagined to be an invisible character at the end of each
line.































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The labeled editing keys of the IBM keyboard can be used while in the screen
mode and have the following functions:

Four cursor keys - These keys, located on the numeric
keypad, move the cursor in the direction of the arrow.

Home - moves the cursor to either the beginning of the
text buffer or the end, depending on the current
direction (which is controlled using keys described on
the next page).

End - moves the cursor to the end of the next or
previous line, depending on the current direction.

Pg Up - moves the cursor up 18 lines in the text,
which provides some overlap on the screen between
adjacent pages.

Pg Dn - moves the cursor down 18 lines in the text.

Del - deletes the character at the cursor position.

Backspace - This key, located on the top row between
the = and Num Lock keys deletes the character to the
left of the cursor.

Tab - Located to the left of the Q key. If special
tabs have been enabled (see T command in last section)
then spaces are inserted into the text until the
cursor reaches the next tab stop. Otherwise, pressing
the tab character inserts an actual tab character into
the text.

Ins - not used.
























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The 10 special function keys on the left side of the keyboard have special
meanings while in screen mode. The layout of the keys is:

F1 - Set direction up F2 - Place select marker
F3 - Find string F4 - Cut selected text
F5 - Find next F6 - Paste in paste buffer
F7 - Move left one word F8 - Move right one word
F9 - Set direction down F10- Reset select


F1 - Set direction up

The functions associated with several of the other keys, namely F3, F5, Home,
and End, require a direction (either forward or backward in the text).
Pressing F1 causes the direction flag to be set in the up direction (backwards
in the text). The direction flag is internal to Edit, and only changes when
keys F1 or F9 (see below) are pressed.

F3 - Find string

When F3 is pressed, Edit prompts you on the bottom row to enter a search
string. You can then type in a character string of up to 50 characters in
length. When typing in the string, you can use the backspace key to correct
mistakes. Terminate the input of the string by pressing one of four keys.
Pressing either the return or F5 key results in the search proceeding from the
cursor position in the direction defined by the current value of the direction
flag. Pressing F1 causes the search to proceed backwards through the text
buffer. Pressing F9 causes the search to proceed forwards through the text
buffer. The direction flag remains in the direction set by F1 or F9 after the
search is completed. The matching function ignores differences in case,
matching lowercase letters with their uppercase counterparts and vice versa.
When the search string is found, the cursor is moved to the beginning of the
matching string in the text buffer. If Edit reaches the end of the text buffer
without finding the string then a message appears at the bottom and the cursor
remains wherever it was before the search began.

F5 - Find next

When F5 is pressed, Edit searchs forward or backward (depending on the current
direction) for the search string defined with the last find command. Same as
F3, except you don't type in a new string.

F7 - Move left one word

Pressing the F7 key moves the cursor to the beginning of the next word to the
left of the cursor.

F9 - Set direction down

Pressing the F9 key sets the direction flag to down (forward through the
text). See key F1 above.








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F2 - Place select marker

Keys F2, F4, F6, and F10 are all associated with the cut and paste function.
Pressing F2 enables the select operation, placing a marker to the left of the
cursor position. After placing the select marker, movement of the cursor
causes the selected text (the text between the select marker and the current
cursor position) to appear in reverse video. The selected text can be cut by
pressing F4 (see below). To reset the select mode, press F10.

F4 - Cut

Pressing the F4 key tells Edit to remove the selected text (which is
highlighted in reverse video) from the text buffer and place it in the paste
buffer. The previous contents of the paste buffer is deleted. Note that the
cut operation is a very useful way to delete large amounts of text, which
provides an extra degree of safety because the deleted text can be recovered.

F6 - Paste

Pressing the F5 key tells Edit to copy the content of the paste buffer into
the text buffer to the left of the cursor position. The content of the paste
buffer is not modified by this command.

F8 - Move right one word

Pressing the F8 key moves the cursor to the beginning of the next word to the
right of the cursor.

F10 - Reset select

By pressing the F10 key you turn off the select mode if for some reason you do
not want to continue a cut operation after pressing the select key.


























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V. Helpful Hints

For normal editing operations, only a subset of the commands discussed above
is needed. To create a new file, you run Edit, go to screen mode with the S
command, and enter your text. Then you leave the screen mode with a CTRL-Z and
create the file using the C command. Leave Edit in this case using the Q
command. To edit an existing file, you run Edit, this time specifying the file
name in the DOS command line or by using the R command. Go to screen mode and
edit the text. Leave the screen mode and then, to save your changes, use the E
command or, to abort the editing session without saving your changes, use the
Q command. These two procedures are all that you really need to remember for
most editing.

Whenever possible, work with files which fit in memory, because Edit is much
more convenient to use in this case. Note that Edit uses all of the memory
that you have installed in your system (up to 640k).

Use the cut function when deleting anything more than a small amount of text.
Not only is it faster and therefore more convenient to use, but because the
removed text is put in the paste buffer, the deletion can be recovered, at
least until another cut operation is performed.

Be careful when doing cut and paste operations on a file which fills up most
of your available memory. If you do a cut operation on a large chunk of text
it may not be possible to paste it all back into the main buffer, because
after a paste operation, two copies of the contents of the paste buffer exist
in memory: one is in the main buffer and one is the paste buffer itself. If
you should happen to get stuck it is always possible to recover without loss
of text by writing the main buffer out with a C or W command.