teacl/doc/INTRO.txt

Introduction to using tecoc

Evocation
---------
As stated in BUILD.txt, tecoc can either be executed directly, or a
file link can be created, or a batch file or shell script can be
created.  For example, if you want to edit a file name MyFile.txt,
if you have a link setup like:

teco -> tecoc

then you could execute:

	teco MyFile.txt

However, if you want to run tecoc directly, you'd have to do:

	tecoc teco MyFile.txt

The extra, and first, argument, "teco", tells tecoc what mode to run
under.  The remainder of this document will assume you have the link
setup.

If you have video mode configured, tecoc nevertheless starts in non-video
mode by default.  To start tecoc in video mode you could do:

	teco -scroll:5 MyFile.txt

This would make the bottom 5 lines used for commands, and the remaining
lines above to be the video display area.

Additionally, video mode can be turned on or off while editing a file,
regardless of the startup parameters.  See "video.txt"

Importantly, the command to save the file and exit is:

	EX followed by two escape key presses

To exit the edit session without saving, do:

	-1EX followed by two escape key presses

Commands
--------

Teco is a character based editor.  This means that teco keeps track of
what character you are at, and not what line you are on.  One normally
edits a file by positioning the point and editing there.

The "$" character functions as the "escape key".  A single $ is used
to separate multiple commands.  Two consecutive escapes, $$, cause
teco to execute all of the commands up to that point.

Other characters, besides $, each have a meaning to teco.  Some
commands consist of more than one character.  Teco commands are
case-insensitive.  This means that "m" and "M" mean the same thing.
In this text I will show the commands in uppercase simply to avoid
confusion between such letters as ell and one.

For example, the "L" command causes teco to move its pointer to the
following line.  If you type "L", nothing happens until you tell teco
to execute is by following the "L" with "$$". So,

L$$

will cause teco to go to the next line.

You may have any number of commands specified before executing them,
for example:

LLL$$

will go down three lines.

Also, commands may take numeric arguments.  For example,

3L$$

will go down 3 lines.

Commands may also be negative, so the following:

-4L$$

will cause teco to go up 4 lines.  Also, since the default argument is one,

-L$$

is the same as -1L$$

In video mode, you will see the changes occur as soon as you execute $$.
In non-video mode, you see nothing unless you ask teco to display a
portion of the text.  For example, if you type:

V$$

you will see the line you are on.

The current character position is always available vie the "." command.
There is also the "=" command that causes teco to display a value, thus:

.=$$

causes teco to display the current character position.

Teco has many, many powerful commands.  It has loops, conditionals,
variables, etc..  Each letter has a different function.  See the
included documentation.


Macros
------

A series of commands, since they are only letters, may be entered into
a text file.  A user may tell teco to read and execute the commands in
one of those files.  The name associated to that set of commands is the name of
the file they are located in (minus the .tec extension).  The command
used to execute a macro file is "EI", thus, for example, if you have a
macro file named "ab.tec" located in the TEC_LIBRARY directory,
executing:

EIab$$

will cause teco to execute the commands located in that file.

In this example, the command is "EI".  It takes a trailing string argument
"ab", and the "$$" means execute it.


Moving On
---------

To learn more, I suggest you read the following, included, documents in
the order shown:

	Summary.pdf
	blake-notes.txt
	teco-manual.txt
	wchart.txt
	
Many of the other documentation files are either historical or provide
greater, tecoc specific, information.