TEACH TEACH                       Last revised, A.Sloman   22 Jan 1997
(WARNING: Modified  22 Jan 1997)

This is a modified version of the standard Poplog introductory "TEACH"
file. This version is designed to go with the Poplog Menu mechanism.

If you do not have a "toplevel" Poplog menu visible when you start up
(a vertical panel of mouse-selectable buttons, with "Toplevel" in the
title bar) then do the following

1. Press the ENTER key (usually on the extreme right)
   The text cursor should jump up to the `status' line.
   Alternatively, you can use CTRL G for ENTER.
2. Type: menu
3. Press the RETURN key (usually to the right of the alphabetic keys)
   If you have no RETURN key, or it does not work you can use CTRL M

This should bring up the Pop-11 control panel. It's location may not be
ideal, so you can move it if necessary, using the middle mouse key
with the mouse pointer on the horizontal "title" bar at the top of the
panel.

Now read on.

-- HOW TO READ POPLOG TEACH FILES -------------------------------------

Before reading on, experiment with the PageUP and PageDown buttons on
the Toplevel menu to get a feel for how to look at different parts of
this document. Also try the arrow keys at the right of the keyboard.
Then come back and read on. Also use the "mouse" pointer to point at
different bits of text, click with the left mouse pointer, and see how
the "VED cursor" moves to the new location. Notice how the line number
changes when you do that.

-- WARNING: LABELS ON KEYS MAY BE MISLEADING IN VED -------------------

In this editor, the PageUP and PageDown keys on the right hand keypad
(also labelled 9 and 3) are used for small diagonal moves (UP Right and
Down Left) in this editor.

If you have two "function key" panels to the right of the main keyboard,
the smaller one including INSERT HOME PAGEUP at the top, then you can
use the PAGEUP and PAGEDOWN keys on that panel to move up and down the
file you are reading.

If you are using a Sun SLC workstation (marked Sparc station SLC on the
base, under the monitor), you will not have that extra panel. Instead
you can use the keys on the top marked R2 and R5 (also marked PrSc and
/) for the SCREENUP and SCREENDOWN functions. They are slightly
different from PAGEUP and PAGEDOWN, but you can ignore the difference.

The arrow keys on the right are used for small moves Up Down Left Right,
and the keys on the bottom right marked 0 and DEL are used to move a
word at a time, left or right. Experiment with all of those.

Later you will also learn to use the function keys on the top, marked
F1 to F10 (or F12) for things like marking a range of text, deleting
part or all of a line, moving or copying a marked range, and so on.

-- THE STRUCTURE OF THIS FILE -----------------------------------------
Most Poplog documentation files include an index, or table of contents.
The index is built from the section headers in the file. There are
various slightly different formats for section headers and file indexes.
The header at the top of this section, using rows of hyphens, is an
example.

Sometimes the index is at the top of the file. Sometimes it is
elsewhere. You can go to the index from the text in the file, or from
the index to the text using the "GoSection" button on the toplevel menu.
Try clicking on the GoSection button with the left mouse button. That
will take you to the index for this file. Then choose a selection by
clicking on it, then click on GoSection again to go to that section.
Then come back to the first section to read on from here.

An alternative to clicking on the GoSection button is to give the
"ENTER g" command. Press the "ENTER" key on the right, to make the VED
cursor (not the mouse cursor) move to the "status line" (or "command
line"). Then type "g" then press the "RETURN" key. We summarise that by
referring to the "ENTER g" command. If that command is still visible on
the status line, you can just press the REDO key (usually the "-" key on
the right hand numeric key pad). That key always repeats the last
ENTER command.

-- LEAVING POPLOG -----------------------------------------------------

If you are using the VED menu system, the "ExitAll" option, on the
Toplevel menu will terminate your session with VED and Poplog. You can
also exit by pressing the ENTER key (on the right usually) then typing
"bye" then pressing RETURN (i.e. give the "ENTER bye" command).

Warning on: HP Xterminals, and on some PCs the key marked ENTER to the
left of the numeric keypad (is not treated as ENTER by VED: that's the
RETURN key). The real ENTER key is normally on the extreme right, except
on a Sun3, which treats L10 (on the left) as ENTER.

When you leave VED, it may report that you have some "changed" files and
ask if you want to "write" them to the disk. Type "y" to ensure that
your work is saved "n" to quit without saving the file, and "c" to
continue editing the file. If you are using XVED you will be given a
control panel with three buttons, instead.


-- RESTARTING VED AFTER LEAVING IT ------------------------------------

After you leave VED and Poplog by using the "ENTER bye" command, you can
restart VED later on, by typing, in a Unix xterm window,

    xved

to get the multi-window X window version of VED, or

    ved

to get the "plain" single window version.

Then when VED has started up give the

    ENTER teach teach

command to re-select this file, or click on the TUTORIAL button on the
Toplevel control panel.

To get back to the last section you were reading, you can use the
GoSection button on the Toplevel control panel to go to the section you
wish to start from. Or use the "ENTER g" command.

Alternatively you can get back to the required place by clicking on the
PageDown option, or using the ScreenDown key or PageDown key (if your
keyboard has one). (Later you will learn other ways of traversing
files.)

Try leaving VED with the "ENTER bye" command, then restart using the
"ved" or "xved" command. Then get back to this point using the PageDown
key on the keyboard or the PageDown mouse option on the control panel.

If you wish to start off VED with one of your own files rather than a
teach file, use the "ved" or "xved" command with your file's name. I.e.
you can type this to unix:

    ved myfile

or
    xved myfile

The second one starts up multi-window Xved. You won't need to start one
of your own files until you have learnt more from reading the teach
files.


-- WHAT IS THE POPLOG TEACH SYSTEM? -----------------------------------

The "TEACH" program uses an editor (word processor) called VED, which
displays text in 'teach files', and can be used to read, create, or
modify text files, like the one you are now reading. There are two
versions: standard VED, which works on a wide range of terminals, and
XVED which works only with the X window system, on workstations and X
terminals.

XVED allows each file to occur in a different window on the screen.
Standard VED uses only one window (often the whole screen) which can
then show one or two files at a time. From now on "VED" is used to refer
to both systems. VED can be driven either by keyboard commands and
function keys, or by menus. You should by now have a VED menu, called
"Toplevel" on your screen. If not, press the ENTER key (usually at the
extreme right of the keyboard), type "menu" and press the RETURN key
(usually to the right of the main typing keys). I.e. give the
    ENTER menu
command.

VED files can be of varying length. Most are too long to be completely
visible at once. So there is always only a subset shown, called the
"viewing window".

You can control which portion of the file is visible in the viewing
window by using the PageUP and PageDown menu buttons, or by using the
corresponding keys on your keyboard, usually marked with an arrow
pointing up or down, except on SPARCStations, where the keys may be
labelled R2 and R5 (on the right).

[[[ NB. You will need to use the keyboard map for your terminal ]]]
[[[             Ask for help if necessary                       ]]]
[[[ NCD Xterminals and HP Xterminals are different from Sun keyboards ]]]
[[[ Alphastation keyboards are similar to NCD Xterminals ]]]
[[[     PC keyboards are different again    ]]]

Often instead of using a mouse it is convenient to use a function key
on the keyboard to traverse a VED file. If you have a keyboard with a
PageDown and PageUp keys you can use them to move up and down a
screenful at a time. Try them. (Remember: never hold a function key
down: press it and release it immediately. Repeat if necessary.)

If you are using a Sun3 or Sun SLC keyboard there will NOT be a middle
keypad with Page Down and Page Up. Instead you can use the keys marked
R5 or / (Screendown) and R2 or PrSc (Screenup) to move down and up.
Watch what happens to the VED cursor when you use these keys.

Alternatively you can simply use the ordinary keyboard and the ESC key
and CTRL key (usually both are on the left).
    ESC v   = ScreenUP
              (press ESC then release it, then press "v").

    CTRL-v  - ScreenDOWN
              (hold the CTRL key, and while it's down press "v")

You can decide whether you prefer to use the keyboard keys or the mouse
menu to move the viewing window up or down the file. Different people
have different preferences.

Press PageUp or SCREENUP then PageDown or SCREENDOWN keys or key
combinations, alternately, several times, until you feel sure you know
how to control movement from one screenful of text to another. Then read
on.

-- SMALLER MOVES AND 'KEYPAD' KEYS ------------------------------------

Sometimes, it is inconvenient for the cursor to move a whole screenful
if all you want to see is just one or two more lines. On the right hand
side of  many keyboards is a 'Keypad'. VED allows you to use the keys on
the keypad for small moves up down, left, right, or diagonally. On your
keyboard map look for keys marked CHARUP, CHARDOWN, CHARLEFT, CHARRIGHT,
and perhaps CHARUPLEFT, CHARDOWNRIGHT, etc.

On some keyboards these are the keys with "arrows" on them. On some they
are the numbered keys on the keypad, often 8(charup), 2(chardown),
4(charleft) and 6(charright). Sometimes they are R8(Up), R14(Down),
R10(Left), R12(right).

These keys can be used to move the cursor in small steps. Find those
CHARUP, CHARDOW, CHARLEFT and CHARRIGHT keys, and others that look as if
they might be concerned with cursor movement, and try them out. If there
is an "LF" key on your terminal you can try that too - it may have the
effect of NEXTLINE, i.e. take the cursor to the beginning of the next
line. (If not CTRL-j will have the same effect.)

Warning: some inferior terminals have a numeric keypad but don't permit
it to be switched to send the special characters: they just send
numbers.

If your keyboard's numeric keypad works with VED, it may function
something like this (press CHARDOWN repeatedly till all 9 boxes are
visible).
                                    ____________________________
Experiment by pressing the keys     |7   UP  |8   UP  |9   UP  |
and see how the cursor can be made  |   LEFT |        |  RIGHT | Can you put
to move in any of eight directions. |________|________|________| the cursor in
                                    |4       |5       |6       | box 5?
                                    |  LEFT  |        |  RIGHT |
If you move far off to the right,   |________|________|________|
text 'scrolls' or jumps left.       |1  DOWN |2  DOWN |3  DOWN |
Move the cursor left again, to      |   LEFT |        |   RIGHT|
bring it back.                      |________|________|________|

On some SUN workstations, the 1 and 3 keys move a "word" at a time left
or right, instead of a character at a time. On some Sun3 terminals you
may have to use R4 and R6 for wordleft and wordright.

If you press (and release) the ESC key immediately before pressing the
CHARUP, CHARDOWN, CHARLEFT, CHARRIGHT keys, that will cause the
VED cursor to make a bigger move, up, down, left or right.

This should be shown on your keyboard map, if you have one, as
"charuplots", "chardownlots", etc.

Instead of using the ESC key, the 5 key on the numeric keypad can be
pressed just before an arrow key to make the move bigger. E.g.
try 5 and 2 twice, then 5 and 8 a few times. If you press the 5 key
twice in a row it will make the current line the middle of the window.


-- USING KEYPAD "MOVE" KEYS TO MOVE THE VISIBLE WINDOW ----------------

If you try to move the cursor up or down past the boundary of the
current visible 'window', the file 'scrolls' down or up, as if you were
pushing the window in the same direction as the cursor. Try pushing the
visible window up by using the CHARUP key to get to the top of the
window, then go on pressing it repeatedly. Then try with CHARDOWN.

You'll find that if the cursor is at the left of the screen and you try
to move it further left, (using THE CHARLEFT key) then it will jump back
to the end of the previous line.

Note that you can also move the VED cursor by using the mouse. Point at
the desired location with the mouse pointer, then click on the left
mouse button. Whether you prefer the mouse or the keypad is up to you.


-- HOW TO PRESS KEYBOARD KEYS -----------------------------------------

Be careful when pressing keys NOT to HOLD them down: let go quickly.
I.e. just tap the keys. If held down for more than about half a second
many keys will behave as if they are being pressed repeatedly.

Exceptions are the keys, marked "Control" (or "CTRL") and "Shift" which
you have to HOLD down whil you tap on another key. These are called
"modifier" keys, as they change the signals sent by other keys. Most
keys are not modifier keys: they send their own signals.

Read on, and make notes as you go, to help you remember what you read.
Otherwise you are likely to forget.


-- DELETING CHARACTERS --------------------------------------------------

Put the VED cursor in the space below this paragraph. Type in a few
words. You can correct errors one character at a time by pressing the
CHARDELETE key (often marked as "DEL", or "Delete"). Try it.

On some keyboards the key marked as "BS" or "Backspace" will also
delete. However, it may delete the character UNDER the cursor
(sometimes referred to as "DOTDELETE", i.e. delete on the dot),
whereas the DEL key deletes the character to the LEFT of the cursor.
On some VED setups, the BACKSPACE key merely moves the VED cursor left,
without deleting anything.

Try typing in some text below this line.

Here ->

Then press the CHARDELETE and BACKSPACE key to see what happens. Try on
the right of the text and in the middle of text.

Try removing all your words then pressing the CHARDELETE key a few more
times - some of the TEACH text will disappear. Dont't worry! It's only
your own temporary copy of the TEACH file that's being deleted.

The text you see on the screen is a copy of a file held on a magnetic
disc attached to the computer. VED (the editor used by TEACH) treats all
TEACH files as 'write protected' so you won't mess up the file by typing
words (or deleting words) on the screen. Practice typing and deleting
text with the CHARDELETE key. Then read on.

-- DELETIONS USING MENU BUTTONS ---------------------------------------

Make sure the "Toplevel" control panel is visible. If not, give the
"ENTER menu" command to make it visible. Then use the left mouse button
to click on the panel marked "Delete..."

This will bring up a new control panel, or menu, which has several
buttons relevant to deleting portions of text, including:

    DelLine     DelLineLeft     DelLineRight    DelWordLeft

etc.

You can use these to delete larger chunks of text than one
character at a time. E.g. you can delete a whole line or a whole word
(to left or to right of the current VED cursor). Try using them on a
portion of this file, higher up, which you have already read. (I.e. move
the VED window up to experiment with them).

Experiment with several buttons whose names start "Del", e.g. "DelLine",
which deletes the whole line the VED cursor is on. "DelLineLeft" deletes
text to the left of the VED cursor, "DelWordRight" deletes the word or
part word, or space, to the right of the current VED cursor. (Ignore
DelMarkedRange: you won't yet know how to create a "Marked Range". When
you do, that button can be used to delete it.)

There are also "function" keys on the top row of your keyboard (e.g. F3,
to F7) that perform similar delete operations. Check using your VED
keymap. On most terminals you will find the following:

    Key   function      alternative name

    F3 = DelLineLeft    CLEARHEAD
    F4 = DelLine        LINEDELETE
    F5 = DelLineRight   CLEARTAIL
    F6 = DelWordLeft    WORDLEFTDELETE
    F7 = DelWordRight   WORDRIGHTDELETE

Try those keys, on bits of text above.

When you have deleted a line or portion of line you can "yank" it back,
possibly in a different place if you have moved the VED cursor, by
repeating the function key preceded by pressing the ESC key.

Use F4 to:

DELETE THIS LINE

Then use ESC F4 to yank it back.

The keys F6 and F7 normally delete individual words to the left and
right of the current VED cursor location. Try them on a bit of this file
that you have already read. (Don't worry: your deletions will not change
the "master" version of this file stored on the disk as this is not
"your" file: it is a "teach file".)

-- UNDOING DELETIONS --------------------------------------------------

Note that some of the buttons on the "Delete..." menu have names that
start with "Yank". They can be used to re-insert the last piece of text
deleted. YankLine will re-insert the last complete line deleted using
DelLine. YankPartLine will re-insert the last portion of a line deleted
with one of:

    DelLineLeft         (Or key F3)     (CLEARHEAD)
    DelLineRight        (Or key F5)     (CLEARTAIL)
    DelWordLeft         (Or key F6)
    DelWordRight        (Or key F7)

For now you can ignore the other menu buttons on the delete menu.

You can also delete individual characters using the Menu Buttons on the
Delete... menu. Try them on some text you have already read. Try out
only the buttons labelled

    DelCharLeft
    DelCharHere
    JoinLine

If you click on ClearBuffer it will empty the file you are currently
reading, so don't!

The DelThisFile menu button tries to remove the file from the disk also.
It is useful for your own old files, but can't be used on a "teach"
file, like this one. (You can also use "ENTER deletefile", which
will delete the file without asking whether you really meant it.)

-- THE COMMAND LINE -----------------------------------------------------

Above the text is a strange line containing, among other things, a
number. The strange line is called the 'command line', as you can give
commands using it. It is also sometimes referred to as the 'status line'
because it displays information about the current status of VED.

You have already met some ENTER commands above.

You can now learn to give more commands on the command line/status line
using the ENTER key. (Remember the real ENTER key is not the one marked
"ENTER" to the right of centre of the HP Xterm keyboard. It is the one
on the right of the keypad, or on a Sun3 it is key L10 on the Left.

If you don't have a clearly identifiable ENTER key, you can instead type
CTRL G, i.e. press down the "Control" key and whilst holding it down tap
on the G key. The "Control" key is sometimes marked "CTRL".)

The number shown on the status line is the line of the file on which the
cursor currently is. If the cursor is on, say, the 71st line of the
teach file, then the number will be 71. Try moving the VED cursor up and
down using the keypad keys, or by pointing and clicking, and watch the
number change.

The command line also reminds you of the name of the file you are
'examining'.

A few commands you can give with the command line will now be
illustrated.

-- JUMPING TO A LINE IN THE EDITOR ------------------------------------

Make a note of the line number the cursor is now at (i.e. the number on
the command line), so that you can come back to it. You can use an ENTER
command to tell VED to go to another line, as follows. E.g. line 1 is
the beginning of the file. So you can go to the beginning of the file by
jumping to line 1 as follows. Find where the ENTER key is on your
keyboard, using the keyboard map if necessary.

    Press: ENTER       (Cursor goes to command line)
    Type:  1           (using the 1 key at the top of the keyboard above
                        the letters, not the 1 on the keypad on right.)
    Press: RETURN

When you have done that, repeat with different numbers, ending with the
number of the line you are on now, so that you can come back here, e.g.
ENTER 430 RETURN

Many commands that you give on the command line are referred to as
"ENTER" commands. Sometimes the word is enclosed in angle brackets
thus "<ENTER>" as a reminder that there is a special key with that name.
Similarly with "<RETURN>". Sometimes the angle brackets are left out.
Sometimes the "<RETURN>" is left out, as all the <ENTER> commands must
end with <RETURN> as otherwise the computer will not know when you have
finished typing the command.

So the command to go to line 23 might be referred to in short form as
"ENTER 23". That's an abbreviation for
    <ENTER> 23 <RETURN>

Many more ENTER commands exist, and you will now learn about a few more
of them. If you can't find the ENTER key, try Control-G, i.e. hold down
the Control key, and tap on the G key. That should work as equivalent
to ENTER, but that will depend on how your keyboard has been set up for
VED.

Another useful ENTER command, mentioned previously, is the ENTER g
command, which gets you to the index (if the file has one). You can use
it now, and then use it again to get back to the section that follows
(GETTING THE TOPLEVEL MENU BACK).


-- GETTING THE TOPLEVEL MENU BACK -------------------------------------

The toplevel menu should have a button marked "Dismiss". If you click
on it, that menu will go away.

You can bring back the top level menu by giving the "ENTER menu"
command. Try the following.

    1. Dismiss the top level menu
    2. Press the ENTER key to get the VED cursor on the command line
    3. Type: menu
    4. Press the RETURN key to make VED obey the command.

The Toplevel menu should reappear.

You can also bring back the Toplevel menu if another Poplog menu is
visible with the "MENUS..." button showing.

Get the Toplevel menu visible, as above. Then click on the 'Mark...'
button to bring up the Mark menu.

Then dismiss the Toplevel menu, by clicking on its Dismiss button.
You can then bring it back by clicking on the Mark menu: look for
the 'Menus...' button. All menus should have a button that brings back
the top level menu.


-- LEAVING TEACH (AND POPLOG) -----------------------------------------

One of the important commands using the <ENTER> key is telling the
system that you wish to leave the editor, and Poplog. If the Toplevel
menu is available you can click on "ExitAll". But you can also leave
Poplog by means of an ENTER command, as follows.

Read on a bit first (up to the asterisks you'll find below). To leave
the editor, and Poplog, you

    Press: ENTER            (puts the cursor on the command line)
    Type:  bye              (the command you want to give)
    Press: RETURN           (that says go ahead and do it)

This will terminate the session using TEACH, and tell the operating
system that you have (for now) finished with Poplog. If your Poplog
process was running in a dedicated window, you will then lose the
window. When you next log in the window will be recreated as normal.

If you want to start up Poplog again without logging out and logging in
again, it is easy if you have a unix "xterm" window available. Simply
type the following command in it:
    ved startup
or
    xved startup

and that will start VED going with the file called 'startup' in your
directory.

If you do not have a unix window available your window manager menu may
have been set up to give you the option to start a new xterm window. You
can select that option as follows.

Move the mouse pointer to the grey background on the screen. Press the
left button and hold it down. A menu panel should appear. Slide the
pointer down to the xterm option and then release it. A new xterm window
will appear in which you can give xterm commands.

You will then be talking to the operating system, which will give you
its prompt, usually either '$' or '%', or possibly '>'.

You can then give commands that the operating system understands. E.g.
you can exit that window, by typing "exit" to it.

See below for logging out completely.

You may wish to practice leaving VED and starting up again. You can get
back to reading the same teach file as before by giving the same
commands (or menu options) as before. You can then jump to the required
line number using the ENTER command shown you above, if you remember the
line number first, e.g.
    ENTER 536

NB after logging out, on some machines you'll have to press the <RETURN>
key once or twice to 'wake up' the computer, before you can log in
again.

Before you try all that, read on till the asterisks, below. When you
restart VED after leaving Poplog, VED will not remember exactly what you
had been doing before. So you should make a note of the line number you
want to return to, so that when you log back in you can get back here.

When you restart VED, if your VED initialisation file has been set up to
start the menu system, you will automatically get the Toplevel menu when
you start. If not, you will have to give the "ENTER menu" command to get
the menus. You can then click on START to get this teach file back.

Now try leaving Poplog using "ENTER bye" (as described above). Then come
back to POP-11.

If necessary, start a new xterm window as described above. (First use
the PageUp key to go back and re-read the instructions so that you are
sure you know what to do to get back here. Make notes to help you
remember.)

        ********************************************************

-- LOGGING OUT COMPLETELY ---------------------------------------------

Before you log out make sure that any files that you have created have
been saved in the disk connected to the computer. You can easily do that
by leaving Poplog via the ExitAll button or the "ENTER bye" command.

After quitting all Poplog processes you may be able to log out by using
the mouse and clicking with the left button on a small window on your
screen labelled "Exit" or "Quit" or "Quit X". For example if you are
using an X terminal it will probably have been set up like that.

-- REFRESHING THE WINDOW ---------------------------------------------

VED's "refresh" facility can be used to re-display the text that is in
the VED buffer. Occasionally, the text will become jumbled on the
screen. This could happen if the computer operators sent out a broadcast
message. Your text in the VED buffer is then unchanged, but what is on
the screen doesn't correspond to it. So you need to "refresh" the
screen.

To refresh the screen you can either use the menu facility or a keyboard
key.

1. Using the menu:
    a. Select the Editor... button on the Toplevel menu, to get
       the editor menu.
    b. Select the "Refresh" key on the editor menu.

If you try it, you may see this text on the screen being re-written.
However, it may happen so fast that you don't see it!

2. Using a keyboard key.
Use your keyboard map to find which is the REFRESH key. For instance
on an NCD X terminal you should find that if you first press the F10
key in the top row of your keyboard it will refresh the screen. On the
Sun3 Xterminal it may be L1.

Another way to refresh, on most keyboards, is to use "Control-L". That
is
    a. Hold down the Control (or CTRL) button (usually on left), and
       keep it down.
    b. Press the "L" key, but DON'T keep it down. (Just TAP it once.)
    c. Release the Control button.


-- DIFFERENT SORTS OF KEYS --------------------------------------------

Several of the VED commands that you will learn require two or more keys
to be pressed. However, there are different kinds of multi-key commands.

Most keys send a signal to the computer when pressed. But some keys
don't do anything on their own. Rather they are held down to change the
effect of other keys: they are "modifier" keys.

The Control key, previously mentioned, is one example. SHIFT is another
example. If you hold it down (try it), nothing happens. But if you press
some letter keys while you hold it down, capital letter appear on the
screen instead of lower case letters. Sometimes you will accidentally
press a key labelled "Caps Lock". That changes the keyboard so that
all letters are typed as capitals. Press it again to undo the effect.
Usually the keyboard has a light (perhaps top right) that goes on if the
keyboard is in Caps mode.

Another key that does nothing on its own is the Control or CTRL key. You
use it to modify other keys. The effect varies according to how your
computer has been set up. For example, on most systems that run Poplog,
pressing the "C" key while CTRL is held down causes an "interrupt". You
can try that now. Since nothing else is happening to be interrupted, you
should not see any effect.

On some keyboards there is also a key marked "FUNCTION" or "META" or
"Convert Function", or a key with a diamond shape, usually next to the
space bar. These keys, like SHIFT are used to alter the function
performed by other keys. So pressing them alone will do nothing. They
may not have been set up to do anything useful for you. (They can be
useful with XVed.)

You will learn about the effect of these keys later on. The main point
for now is that these "modifier" keys (SHIFT, CTRL, FUNCTION) are the
only ones that are held down for any length of time. The ENTER key, the
ESC key (referred to later) the keys with arrows on, the 'key-pad' keys
etc. are not modifier keys, but send their own signals, so you don't
hold them down, but press them lightly once. A light "tap" will usually
suffice.


-- BIGGER JUMPS -------------------------------------------------------

On most keyboards set up for VED you can transform a small move up,
down, left or right to a bigger move by pressing <ESC> key and then the
keypad key in order to get bigger jumps. E.g. try ESC followed by the
CHARUP or CHARDOWN key a few times. (Usually keypad 8 or 2, on the
right). Or use the "5" keypad key instead of ESC.

The same effect can be achieved via menus. First select Move1... on the
Toplevel menu. Then try the UpLots and DownLots buttons. See how the
VED cursor moves. (The cursor may become hollow while the mouse pointer
is out of the VED window.)


--MOVING THE CURSOR A WORD AT A TIME ------------------------------------

Two of the keys are known as WORDLEFT and WORDRIGHT. Note how those two
keys make the cursor move about. See what happens if you press WORDLEFT when
the cursor is at the beginning of a line. Often these functions are
mapped onto they keys labelled "0" and "." at the bottom of the right
hand keypad, i.e. next to the ENTER key. On the Sun3 Xterminal they are
R4 and R6.

For now you can ignore the other keys on the Keypad, apart from ENTER,
which you'll use for putting the cursor on the 'command line' to give
special commands.

-- READING OTHER TEACH FILES ------------------------------------------

There are many TEACH files on many different topics. You can temporarily
transfer to another teach file and then come back to this one, as
follows. There is a teach file called WINDOW, which will show you how to
enlarge the visible 'window' so that you can see more of the file at
once. (You may have been wondering about that.) To read it, do the
following:

    Press: <ENTER>
    Type:  teach window           (If you make a mistake use the DEL key)
    Press: <RETURN>

This will get you the TEACH WINDOW file. Try it, and obey the
instructions. When you have finished you can "quit" the file by giving
the command
    <ENTER> q <RETURN>


-- RE-DOING THE LAST COMMAND ---------------------------------------------

(N.B. read down to the next main heading before trying the instructions
in this section.)

Try the following:

    ENTER teach window

that will get you a new window. Then Quit that window by putting
the mouse in it and typing ESC q.

When you get back to this window, the "teach window" command will
still be on the command line. You can re-do that command by pressing the
REDO button. Look at your keyboard map to see where it is. Usually the
"-" on the right hand numeric keypad will have that function. If it
doesn't work you can instead use the key sequence
    ESC RETURN
as equivalent to REDO.

Now try REDO, to re-do the "teach window" command. Then quit that
window and come back here.

The REDO button is also useful with the ENTER g command. Try ENTER g  to
go to the table  of contents of  this file. then  select a section,  and
press REDO, then press REDO to get  back to the table of contents,  then
come back to the next section, on "QUITTING SEVERAL FILES IN A ROW"


-- QUITTING SEVERAL FILES IN A ROW ------------------------------------

There are many hundreds of help and teach files in Poplog. Sometimes
after looking at three or four files you want to quit them all, and
come back to the previous file you were working on. You can quit a
file with the ENTER q, command, then press REDO until you get back
here. E.g. give these four commands, to bring up four new teach files:

    ENTER teach ved
    ENTER teach mark
    ENTER teach vedpop
    ENTER teach respond

This will get four new files. Quit the last one by means of the
    ENTER q
command.

Then press REDO three times to come back here.

If you press it, the command 'q' will be obeyed again and so you will
quit this file. You can come back here by typing 'teach' to POP-11 and
then jumping to this line. Try it. As you have found, ENTER q only quits
the current file.

If you press it too many times it will quit all the files and take
you out of VED or XVED.


-- SOME REVISION QUESTIONS --------------------------------------------

You should make notes of all the important points concerning the use of
TEACH and check with your course tutor about any confusions. Here's a
brief list:

    Which keys are held down to modify others, and which send
        their own signals to the computer?

    How do you move the cursor up, down, left, right in the teach file?

    How do you go up a page, down a page?

    What is the difference between the mouse cursor and the VED
        cursor?

    What does the ENTER key do?

    Which control key is equivalent to the ENTER key?

    Which key sequence is equivalent to REDO ?

    What does pressing the ESC key then W do?

    What does ENTER q do?

    What does ENTER q do if there is only one file left in VED?

    How do you get back from Unix to reading a TEACH file?

    Which sequence using ESC quits the current file?

    How do you get the cursor onto line 73 of a file?

    How can you get the cursor to the top of the file?

    How do you change the size of the TEACH window?

    How do you 'refresh' your VED window?

    How do you leave TEACH (and VED) and Poplog?

    How do you LOG OUT?

    Which keys move the cursor a word left or right?

    Which key deletes
        The whole of the current line?
        The left part of the line?
        The right part of the line?

    What does CTRL L do?

-- WHICH FILES TO LOOK AT NEXT ----------------------------------------

You should now go on to read TEACH VED to find out how to use the text
editor to make your own files. But if you need a rest first (you
probably will!) you can log out now, and come back later. Next time, log
in as before, and start up VED

When VED has started up, type

    ENTER teach ved

then press RETURN.

Other files you could now read are:

    TEACH * VED
            - more on VED - learning to create your own file
    TEACH * MARK
        - learning to mark a range in a file
    TEACH * RHYME
        - will give you a lot of practice, including reading and sending
        messages.
    TEACH * LMR
        - using "load marked range" in a program file
    TEACH * VEDPOP
        - using the editor to create POP-11 program files

For more advanced users only:

    TEACH * TEACHFILES
        - overview of TEACH documentation in the Poplog system
    TEACH * LOCALINDEX
        - List of teach files available in this department.
    HELP  * HELPFILES
        - overview of HELP documentation
    HELP * LOCALINDEX
        - List of help files available in this department.

-- USING THE TABLE OF CONTENTS ----------------------------------------

CONTENTS of this file are listed below.
You can go to any section by putting the cursor on one of the lines
below then doing:
    <ENTER> g <RETURN>

Alternatively, click on the GoSection menu button. Use the same action
to get back to this index later.

 -- HOW TO READ POPLOG TEACH FILES
 -- WARNING: LABELS ON KEYS MAY BE MISLEADING IN VED
 -- THE STRUCTURE OF THIS FILE
 -- LEAVING POPLOG
 -- RESTARTING VED AFTER LEAVING IT
 -- WHAT IS THE POPLOG TEACH SYSTEM?
 -- SMALLER MOVES AND 'KEYPAD' KEYS
 -- USING KEYPAD "MOVE" KEYS TO MOVE THE VISIBLE WINDOW
 -- HOW TO PRESS KEYBOARD KEYS
 -- DELETING CHARACTERS
 -- DELETIONS USING MENU BUTTONS
 -- UNDOING DELETIONS
 -- THE COMMAND LINE
 -- JUMPING TO A LINE IN THE EDITOR
 -- GETTING THE TOPLEVEL MENU BACK
 -- LEAVING TEACH (AND POPLOG)
 -- LOGGING OUT COMPLETELY
 -- REFRESHING THE WINDOW
 -- DIFFERENT SORTS OF KEYS
 -- BIGGER JUMPS
 -- READING OTHER TEACH FILES
 -- RE-DOING THE LAST COMMAND
 -- QUITTING SEVERAL FILES IN A ROW
 -- SOME REVISION QUESTIONS
 -- WHICH FILES TO LOOK AT NEXT
 -- USING THE TABLE OF CONTENTS

--- $poplocal/local/teach/teach
--- The University of Birmingham 1996.  --------------------------------
