Version II.0, February 1979
This text editor is intended for use on systems that do not
have powerful screen terminals. It is designed to be very similar to
the text-editor which accompanies DEC's RT-11 system.
Its name is pronounced: Yaw-loo-ee.
The editor assumes, but is not dependent on, the existence of the workfile text. Upon reading it YALOE will proclaim ‘workfile STUFF read in’. If it does not find such a file, it will proclaim ‘No work file read in’. This means that you entered YALOE with an empty workfile. From this point you may create a file in YALOE; and when you exit by typing ‘QU’, your workfile will no longer be empty.
The editor operates in one of two modes: Command Mode or Text Mode. In command mode all keyboard input is interpreted as commands instructing the editor to perform some operation. When you first enter the editor you will be in the Command Mode. The Text Mode is entered whenever the user types a command which must be followed by a text string. After the command F(ind, G(et, I(nsert, M(acro define, R(ead file, W(rite to file, or eX(change has been typed, all succeeding characters are considered part of the text string until an <esc> is typed. Note: when typed <esc> echoes a ‘$’. The <esc> terminates the text string and causes the editor to re-enter the Command Mode, at which point all characters are again considered commands.
Note: Follow command strings in YALOE with <esc><esc> to execute them. (This is unlike the rest of the systems ‘immediate’ commands.)
1.4.1. Special Key Commands
Various characters have special meanings, as described below. Some of these apply only in YALOE. Many have similar effects in the rest of the system; for these the ASCII code to which the system responds as indicated can be changed using the program SETUP, described in Section 4.3. (<esc> is the most particular anomaly to YALOE.)
RUBOUT <linedel>
*IDALE AND
KEITH<CTRL X>
*
A <linedel> would cause deletion of only
KEITh; CTRL X would erase the entire command.
All other control characters are ignored and discarded by YALOE.
Command Arguments
A command argument precedes a command letter and is used
either to indicate the number of times the command should be performed
or to specify the particular portion of text to be affected by the
command. With some commands this specification is implicit and no
argument is needed; other commands, however, require an argument.
Command arguments are as follows:
1.4.3 Command Strings
All EDIT command strings are terminated by two successive <esc>s. Spaces, carriage returns and tabs (CTRL I) within a command string are ignored unless they appear in a text string.
Several commands can be strung together and executed in sequence. For example:
*B GTHE INSERTED$ -3CING$ 51< GSTRING$$
As a rule, commands are separated from one another by a single
<esc>. This separating <esc> is not needed, however,
if the command
requires no text. Commands are terminated by a single <esc>; a second
<esc> signals the end of a command string, which will then be
executed. When the execution of the command string is complete, the
editor prompts for the next command with “*”.
If at any point in executing the command an error is encountered, the command will be terminated, leaving the command executed only up to that point.
1.4.4 The Text Buffer
The current version of your text is stored in the Text Buffer. This buffer's area is dynamically allocated; its size and the room left for expansion may be ascertained by using the ? command.
The editor can only work on files that fit entirely within the Text Buffer.
1.4.5 The Cursor
The “cursor” is the position in your text where the next command will be executed. In other words it is the current “pointer” into the Text Buffer. Most edit commands function with respect to the cursor:
1.4.6 Input/ Output Commands
The L(ist command prints the specified number of lines on the console terminal without moving the cursor.
*4L$$
The V(erify command prints the current text line on the terminal. The position of the cursor within the line has no effect and the cursor is not moved. Arguments are ignored. The V(erify command is equivalent to a 0LL (list) command.
The W(rite command is of the form
*W<file title>$File title is any legal file title as decried in section 1.2 less the file type. The editor will automatically append a ‘.TEXT’ suffix to the file title given unless the file title ends with ‘.’, ‘]’, or ‘.TEXT’. If the filename ends in a ‘.’, the dot will be stripped from the filename. Refer to Figure 2 in section 1.2.14 for details on filename specifications.
The W(rite command will write the entire Text Buffer to a file with the given file title. It will not move the cursor nor alter the contents of the Text Buffer. If there is no room for the Text Buffer on the volume specified in the file title given, the message:
OUTPUT ERROR. HELP!will be printed. It is still possible to write the Text Buffer out by writing it to another volume.
The R(ead command is of the form
*R<file title>$The editor will attempt to read the file title as given. In the event no file with that title is present, a ‘.TEXT’ is appended and a new search is made.
The R(ead command inserts the specified file into the Text Buffer at the cursor. The cursor remains in the Text Buffer before the text inserted. If the file read in does not fit into core buffer, the entire Text Buffer will be undefined in content, i.e. this is an unrecoverable error.
The Q(uit command has several forms
Executing the QU command is a special case of the write command, and the attempt to write out SYSTEM.WRK.TEXT may fail. In this case use the W command to write out your file and then QE to exit the editor.
The QR command is used on the occasions when a Q is accidentally typed, and you wish to return to the editor rather than leave it.
The E(rase command (intended for CRT terminals) erases the screen.
1.4.7 Cursor Relocation Commands
When using character and line oriented commands, a positive (n or +n) argument specifies the number of characters or lines in a forward direction, and a negative argument the number of characters or lines in a backward direction. The editor recognizes a line of text as a unit when it detects a <cr> in the text.
Carriage return characters are treated the same as any other character. For example assume the cursor is positioned as indicated in the following text (^ represents the current position of the cursor and does not appear in actual use. It is present here only for clarification):
THERE WAS A CROOKED MAN^<cr> AND HUMPTY DUMPTY FELL ON HIM<cr>
The J(ump command moves the cursor over the specified number of characters in the Text Buffer. The edit command -4J moves the cursor back 4 characters.
THERE WAS A CROOKED^ MAN<cr> AND HUMPTY DUMPTY FELL ON HIM<CR>
The command 10J moves the cursor forward 10 characters and
places it between the ‘H’ and the ‘U’.
THERE WAS A CROOKED MAN<cr> AND H^UMPTY DUMPTY FELL ON HIM<cr>
The A(dvance command moves the cursor a specified number of lines. The cursor is left positioned at the beginning of the line.
Hence the command 0A moves the cursor to the beginning of the current line.
The command -1A (or -A) moves the cursor back one line.THERE WAS A CROOKED MAN<cr> ^AND HUMPTY DUMPTY FELL ON HIM<cr>
^THERE WAS A CROOKED MAN<cr> AND HUMPTY DUMPTY FELL ON HIM<cr>
The B(eginning command moves the cursor to the beginning of the Text Buffer. Use /J to move to the end of the buffer. Search commands are used to locate specific characters or strings of characters within the Text Buffer.
The G(et and F(ind commands are synonymous. Starting at the position of the cursor, the current Text Buffer is searched for the nth occurrence of a specified text string. A successful search leaves the cursor immediately after the nth occurrence of the text string if n is positive and immediately before the text string if n is negative. An unsuccessful search generates an error message and leaves the cursor at the end of the Text Buffer for n positive and at the beginning for n negative.
1.4.8 Text Modification Commands
The I(nsert command causes the editor to enter the TEXT mode.
Characters are inserted immediately following the cursor until an
<esc> is typed. The cursor is positioned immediately after the last
character of the insert. Occasionally with large insertions the
temporary insert buffer becomes full. Before this happens a message
will be printed on the console terminal, ‘Please finish’.
In response
type two successive <esc>s. To continue, type ‘I’ to
return to the Text mode.
Note: Forgetting to type the ‘I’ command will cause the text entered to be executed as commands.
The D(elete command removes a specified number of characters from the Text Buffer, starting at the position of the cursor. Upon completion of the command, the cursor's position is at the first character following the deleted text.
The K(ill command deletes n lines from the Text Buffer, starting at the position of the cursor. Upon completion of the command, the cursor's position is the beginning of the line following the deleted text.
The C(hange command replaces n characters, starting at the cursor, with the specified text string. Upon completion of the command, the cursor immediately follows the changed text.
eX(change:
The eX(change command exchanges n lines, starting at the cursor, with the indicated text string. The cursor remains at the end of the changed text.
-5Xtext$$
1.4.9 Other Commands
The S(ave command copies the specified number of lines into the Save Buffer starting at the cursor. The cursor position does not change, and the contents of the Text Buffer are not altered. Each time a S(ave is executed, the previous contents of the Save Buffer, if any, are destroyed. If executing the S(ave command would have overflowed the Text Buffer, the editor will generate a message to this effect and not perform the save.
The U(nsave command inserts the entire contents of the Save Buffer into the Text Buffer at the cursor. The cursor remains before the inserted text. If there is not enough room in Text Buffer for the Save Buffer, the editor will generate a message to this effect and not execute the unsave.
The Save Buffer may be cleared with the command 0U.
The M(acro command is used to define macros. A maximum of ten macros, identified by the integer (0..9) preceding the ‘M’, are allowed. The default number is 1. The M(acro command is of the form:
mM%command string%This says to store the command string into Macro Buffer number m, where m is the optional integer 0..9. The delimiter, `%` in this example, is always the first character following the M command and may be any character which does not appear in the macro command string itself. The second occurrence of the delimiter terminates the macro.
All characters except the delimiter are legal Macro command
string characters, including single <esc>s. All commands are legal in
a macro command string. Example of a macro definition:
5M%GBEGIN$=CEND BEGIN$V$%$$This defines macro number 5. When macro number 5 is executed, it will look for the string ‘BEGIN’, change it to ‘END BEGIN’, and then display the change.
If an error occurs when defining a macro, the message
Error in macro definitionwill be printed, and the macro will have to be redefined.
The execute macro command, N, executes a specified macro command string. The form of the command is:
nNm$Here n is simply any command argument as previously defined; m is the macro number (an integer 0..9) to be executed. If m is omitted, 1 is assumed. Because the digit m is technically a command text string, the N command must be terminated by an <esc>.
Attempts to execute undefined macros cause the error message ‘Unhappy macro’. Errors encountered during macro execution cause the message ‘Error in macro’. Errors encountered in macro command syntax cause the message ‘Error in macro definition’.
Help:
The ? command prints a list of all the commands and the sizes of the Text Buffer, Save Buffer, and available memory left for expansion. It also lists the numbers of the currently defined macros.
1.4.1O Summary of All Commands
n - an argument, m - macro number
