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EZ: a text editor I wrote in 1987
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ez.c
/* ez.c
ez.c (c) KindelCo Software Systems, 1987
EZ - The tlw Screen Editor
Author: Charles E. Kindel, Jr. (tigger)
Started: July 17, 1987
Version: 2.03
NAME
EZ - A screen editor.
SYNOPSIS
ez filename
DESCRIPTION
EZ is a screen editor intended for generating and modifying text
files in an interative mode. A window portraying 23 lines of the
text shows the changes or additions to the text as they are made.
A command line at the bottom is reserved for advisory messages
during the edit session.
A cursor in the window shows where the text modification of the file
will occur. The window moves automatically as the cursor is moved
beyond the edge of the window. If the cursor moves below the bottom
margin of the screen, the window moves down to show a lower portion
of the text (assuming more text exists below the current window).
Similarly, if the cursor moves above the top of the screen, the
window moves up to reveal the text above the current window unless
the cursor is already at the top of the screen.
The commands, described below, include moving the cursor, inserting
text, and deleting the text.
On starting up, the text is transferred from the backing store to
the processor memory. A newline is added at the end if one is not
there. At the end of the edit session, the modified text is trans-
ferred from memory to the backing store. Every attempt is made to
avoid the loss of modifications.
The roots of this small editor are found in Cambridge, Massechusettes
where TECO and real-time TECO were developed at MIT.
EXAMPLES
ez filename Edit filename. File may or may not already exist.
(NOTE: This is the ONLY proper usage).
MESSAGES
Usage synopsis given when illegal command form is entered.
The following messages may appear on the command line:
"AT TOP"
"AT END"
"BUFFER MODIFIED. DO YOU WISH TO SAVE MODIFICATIONS? (y or n)."
"EZ version 1.0 - 29-Jul-87."
"New file."
"Read fails!"
"Writing ### bytes to filename."
"Write fails!"
"Move to what line:"
DIAGNOSTICS
Exit status is 0 if the file was found or if a new file is being
edited.
Exit status is 1 if the file exists but could not be accessed.
SEE ALSO
Information regarding TECO and real-time TECO developed at MIT
in Cambridge, Massechusettes.
LIMITATIONS
Text size is limited to 65,000 characters. No repeats, no macros,
no cut and paste, no search, no windows. Tabstops are set to every
4 spaces.
FACILITY
UNIX BSD 4.2 System - ez.c.
MS-DOS PC System - ez.c.
BUILD
On UNIX BSD 4.2 System: make
On MS-DOS PC System (using TurboC): make
(you need Terminal and Xsys routines for the PC.)
BUGS
The text size is limited to 65535 characters. No repeats, no macros, no
cut and paste, no search, no windows. Tabstops are set to every 4 spaces.
REVISIONS
DATE VER NAME CHANGE
July 18, 1987 1.00 Kindel Original
July 19, 1987 1.01 Kindel Attempted compile on some modules.
July 19, 1987 1.10 Kindel Read a file and display the screen.
July 20, 1987 1.20 Kindel Insert characters, Delete characters
(no scrolling)
July 21, 1987 1.30 Kindel Move right, left, up, down.
July 22, 1987 1.35 Kindel Paint screen if you move off of it.
July 23, 1987 1.40 Kindel Buffer delete routines.
July 25, 1987 1.45 Kindel Primitive display deleting.
July 26, 1987 1.50 Kindel Scrolling is attempted.
July 27, 1987 1.70 Kindel Scrolling, Most commands, Move by page,
Move to top, end, etc...
July 29, 1987 1.90 Kindel Beta version. Re-wrote DpDel and cleaned
up display routines.
July 30, 1987 2.00 Kindel Fixed most major bugs. Added go to line
number function. Added beeps.
July 31, 1987 2.02 Kindel More bug fixes. Changed buffer size to
65000 bytes to try to avoid segmentation
faults.
COMMANDS
Commands are implemented by binding each command to a control
character entered from the keyboard. Control characters are entered
by depressing the control key and then one other key simultaneously
(just as with the shift key). The binding of commands to control
keys is shown in the summary below.
Any key input that is not assigned to one of the commands listed
below becomes an insert-character command which causes that character
to be inserted into the text. Control characters inserted into the
text are shown in inverse video, except that the carriage return and
the tab character are displayed as newlines or spaces to the next
tabstop, respectively.
If at the top (bottom) of the text, a command that attempts to move
or delete beyond the top (bottom) of the text generates an appropriate
error message.
A word is interpretted as any sequence of non-whitespace characters.
The following abbreviations are used below:
bob - beginning of text buffer.
bol - beginning of line.
bow - beginning of word.
chars - characters.
eol - end of line.
eow - end of word (first non-whitespace char after word).
eob - end of text buffer.
ABRT Abort the edit session.
If the text has been modified since the beginning of the edit
session or the last write to a disk, a question appears on the
command line:
BUFFER MODIFIED. DO YOU WISH TO SAVE MODIFICATIONS? (y or n).
If the response is 'Y', 'y', or <CR>, the edit session is terminated
without saving the current text; otherwise, the session continues.
DBOL Delete to the beginning of the line.
The chars to the left of the cursor up to the bol are deleted. If
the cursor is at the bol, the previous line is deleted. An error
message is generated if the cursor is at the beginning of the text.
DBOW Delete to the beginning of the previous word.
The whitespace, if any, and then the word to the left of the cursor
is deleted. If the cursor is in the middle of a word, all of the
characters to the left of the cursor up to the beginning of the word
are deleted. An error message is generated if the cursor is at the
beginning of the text.
DCHR Delete char under the cursor.
The character under the cursor is deleted. If the cursor is at the
end of the line, the newline is deleted. An error message is
displayed if the cursor is at the end of the text.
DELP Delete previous character.
The character to the left of the cursor is deleted. If the cursor
is at the bol, the previous newline is deleted and the two lines are
joined. An error message is displayed if the cursor is at the
beginning of the text.
DEOL Delete to the end of the line.
The characters from the cursor to the eol are deleted, including the
newline. An error message is displayed if the cursor is at the end
of the text.
DEOW Delete to the end of the next word.
The whitespace, if any, and the word following the cursor are deleted,
including the character above the cursor. If the cursor is in the
middle of a word, the character above the cursor and the rest of the
word are deleted. An error message is displayed if the cursor is at
the end of the text.
MBOB Move to the beginning of the text buffer.
Moves the cursor to the first character in the text. An error message
is displayed if the cursor is already at the beginning of the text.
MBOL Move to the beginning of the line.
Moves the cursor to the first character of the line or to the first
characterof the previous line if it is already at the bol. An error
message is displayed if the cursor is at the beginning of the text.
MBOW Move to the beginning of the previous word.
Moves the cursor to the first character of the word to the left of
the cursor. If the cursor is at the first character of a word, the
cursor is moved to the first character of the previous word. An error
message is displayed if the cursor is at the beginning of the text.
MEOB Move to the end of the text buffer.
Moves the cursor to the last character in the text buffer. The last
character in the text buffer is always a newline character. An error
message is displayed if the cursor is already at the end of the text.
MEOL Move to the end of the line.
Moves the cursor to the newline character at the end of the line. If
the cursor is already at the end of the line, the cursor is moved to
the end of the next line. An error message is displayed if the cursor
is at the end of the text.
MEOW Move to the end of the word.
Moves the cursor to the position just past the last character of the
next word in the text. If the cursor is already at the end of a word,
the cursor is moved to the next position just past the end of the same
word. An error message is displayed if the cursor is at the end of
the text.
MVDN Move down one line.
Moves the cursor straight down to the same position on the next line.
If the next line does not extend out as far as the current cursor
position, the cursor moves to the end of the next line. If the same
positon on the next line is in the middle of a tab, the cursor is
moved to the next tab stop. If the cursor is on the last line of the
text, the cursor moves to the end of the text. If the cursor is on
the last line of the dislay, the next line is displayed on the bottom
of the screen (the top line on the display is erased). An error
message is displayed if the cursor is at the end of the text.
MVLF Move left one character.
Moves the cursor left one position. If the cursor is at the beginning
of a line, the cursor moves up to the end of the previous line. An
error message is displayed if the cursor is at the beginning of text.
MVNP Move to next page.
Moves the cursor down 22 lines in the same fashion as MVDN. Move to
the end of text if less than 22 lines are left. An error message is
displayed if the cursor is at the end of the text.
MVPP Move to previous page.
Moves the cursor up 22 lines in the same fashion as MVUP. Moves to
the beginning of the buffer if the cursor is less than 22 lines
from the top of the buffer. An error message is displayed if the
cursor is at the top of the text.
MVRT Move right one character.
Moves the cursor right one position. If the cursor is at the end of
the line, the cursor moves to the beginning of the next line. An
error message is displayed if the cursor is at the end of the text.
MVUP Move up one line.
Moves the cursor up to the same position on the line above the cursor.
If the destination line does not extend out to the current cursor
position, then the cursor is moved to the end of the destination line.
An error message is displayed if the cursor is at the beginning of
the text.
MTLN Move to a specific line number.
Prompts the user for a line number and moves to that line. If a line
number is specified that is greater than the end of the buffer then
go to the end of the buffer.
QUIT Write, then quit.
If the text has been modified, the text buffer is written to the
backing store and then the edit session is terminated.
VERS Print version number, refresh display.
The version number and date of last change is printed on the command
line and the display is completely refreshed in case of some
contamination.
WRIT Write text buffer to text.
Save the text buffer to the backing store. The entire text is
written regardless of the position of the cursor.
QUICK REFERENCE
CONTROL
KEY COMMAND DEFINITION
----------------------------------------------------------------
A MBOB Move to bob.
B MBOL Move to bol.
C QUIT Write, then quit.
D DCHR Delete char under cursor.
E DEOW Delete to eow.
F MEOL Move to eol.
G DEOL Delete to eol.
H MVLF Move left one space.
I tab Insert spaces up to next tab stop.
J MVDN Move down one line.
K MVUP Move up one line.
L MVRT Move right one position.
M Start text on a new line.
N MVNP Move cursor up one page.
O MBOW Move to bow.
P MEOW Move to eow.
Q reserved for command macros.
R reserved for repeat command.
S reserved for search.
T reserved for take a line.
U DBOL Delete to bol.
V VERS Print EZ version, refresh display.
W DBOW Delete to bow.
X reserved for recall repeat count.
Y MVPP Move to previous page.
Z MEOB Move to eob.
QUOT reserved for "take next char literally".
Del DELP Delete previous char.
ESC-C ABRT Abort the edit, no write.
ESC-W WRIT Write text buffer to backing store, no quit.
ESC-G MTLN Move to a line.
*/
/*==========================================================================*/
/* ez.c Charles E. Kindel (C) KindelCo Software Systems, 1987 */
/*==========================================================================*/
/* IMPORTS -----------------------------------------------------------------*/
#include <stdio.h>
#include "ez.h"
#include "xsys.h" /* Serial io routines */
#include "disp.h" /* Display routines */
#include "buf.h" /* Buffer routines */
#include "cmnd.h" /* Command loop routines */
/* LOCAL SYMBOLIC DEFINITIONS ----------------------------------------------*/
#define ERROR 2 /* If there isn't a file name no the command line */
/*==========================================================================*/
/* main program */
/* */
/*--------------------------------------------------------------------------*/
int main (argc, argv)
int argc;
char *argv[];
{
/* process command line */
if (argc == 2)
{ BfFileNamep = argv [1];
Xinit (); /* initialize serial io */
DpInit (); /* initialize display */
BfInit (BfFileNamep); /* initialize buffer, and attempt to read the input file */
Cmnd (); /* the command loop */
}
else
fprintf (stderr, "ez: must include file name.\n");
return (ERROR);
} /* end of main */
/*==========================================================================*/
/* END OF ez.c (C) KindelCo Software Systems, 1987 */
/*==========================================================================*/
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