TECO V39 Release Notes
	Mark Bramhall
	13-Jan-1984

	Changes to TECO since TECO V36

This is a (fairly cryptic) list of the changes that have been made between
TECO V36 (the last time the TECO manual was fully up to date) and TECO V39.

User visible differences TECO V36 to TECO V39:

1) DEC Multi-national character set handling
    TECO now fully supports the DEC Multi-national character set.  This
    means that all character codes handled by TECO are 8-bit character
    codes.  This change affects the following:
    a) Many commands use to trim data to 7 bits
	All commands now handle data as 8-bit data.
    b) Output conversions
	If your terminal is a 7-bit terminal (see ET bit 4096) then:
	    i) Unprintable and/or illegal codes in the 128 to 255 range
	       are output as [xy], where the xy is the hexidecimal for
	       the code.
	    ii) Valid DEC Multi-national codes are output as <xy>, where
	       the xy is the LK201 keyboard compose sequence for the code.
	If your terminal is an 8-bit terminal (see ET bit 4096) then:
	    i) Unprintable and/or illegal codes in the 128 to 255 range
	       are output as [xy], where the xy is the hexidecimal for
	       the code.
	    ii) Valid DEC Multi-national codes are output as themselves.
	The scope watch feature (W commands) always uses the [xy] and <xy>
	notation due to internal coding limitations within that feature.
    c) Search string matching
	If generic search matching is enabled (^X = 0) then TECO will match
	characters without regard to case and/or diacritical marks.

2) ET bits
    a) 4096 (8-bit terminal)
	This new ET bit reflects and can change the state of the terminal
	characteristic EIGHTBIT/NOEIGHTBIT.  This bit is initially clear
	if the terminal is set to NOEIGHTBIT; it is initially set if the
	terminal is set to EIGHTBIT.  Changing the bit will cause the terminal
	to change its EIGHTBIT/NOEIGHTBIT characteristic.  TECO will restore
	the terminal to its original state upon exit.
    b) 8192 (accept accent grave, "`", as ESCape during command input)
	This new ET bit is initially clear.  If set, typing an accent grave
	(`) during command input (only!) will have the same effect as
	typing an ESCape.  This random hack was dictated by the new LK201
	keyboard which doesn't have an ESCape key, but does have accent
	grave in the position ESCape used to be in...

3) 0:W (scope type)
    The valid scope types for 0:W are now:
	0	VT52
	2	VT100 in VT52 mode
	4	VT100 in ANSI mode
	6	VT05
	8	VT102 in ANSI mode
	10	VK100 (GIGI)

4) ED bits
    a) 1 - ^ (up-arrow) in search arguments is a literal ^
	If 0, ^ in search arguments means that the next
	character should be interpreted as a control character.
    b) 2 - Disables Yank protection
	If 0, the Y, N, and _ commands are aborted if they
	would result in data being lost.
    c) 4 - Disallow memory expansion when reading in a text page
	If 0, memory is expanded, if needed, so that the whole
	text page fits in the text buffer.
    d) 8 - Reserved by PDP-8 TECO...
    e) 16 - Leaves buffer pointer unchanged on search failures
	If 0, search failures move the buffer pointer to the
	beginning of the text buffer.
    f) 32 - Enable immediate mode commands
	See "Immediate mode commands" below.
    g) 64 - Only move the buffer pointer by one on iterative search failures
	If 0, the buffer pointer moves by the length of
	the search string on iterative search failures.
    h) 128 - Disable scrolling's automatic text buffer display update
	If scroll mode is enabled (7:W <> 0), TECO normally updates the text
	buffer display just before printing its * prompt.  Setting 128 in ED
	inhibits this automatic update (see the immediate ^W command).

5) Immediate ^W command
    If scroll mode is enabled (7:W <> 0) then typing a ^W immediately after
    TECO prompts with its * will cause the text buffer display to be updated.
    This is useful to recover from broadcast messages and/or in conjunction
    with ED bit 128.

6) Local Q-registers
    The set of 36 Q-regs (0-9, A-Z) has been expanded to include a set of
    36 local Q-regs that are unique to each macro invocation level.  The
    standard 36 Q-regs are now called the global Q-regs and remain named
    0-9 and A-Z.  The 36 local Q-regs are named .0-.9 and .A-.Z (i.e., the
    global name preceeded by a dot).  There's a set of 36 local Q-regs for
    each and every macro (Mq) invocation level, including the top (command
    input) level.  When a macro is invoked (via Mq), the current local Q-regs
    are saved and a new set of local Q-regs are created.  When the macro
    exits, its local Q-regs are destroyed and the previous levels local
    Q-regs are restored.  If a fatal error occurs and TECO goes back to
    command level, all local Q-regs from macro invocations are destroyed
    and command level's local Q-regs are restored.  This eliminates the
    need for a macro to save ([ commands) and then restore (] commands)
    Q-regs.  A local Q-reg name can be used in any command that takes a
    Q-reg name.

7) M command extensions
    a) A normal M command (Mq) creates a new set of 36 local Q-regs and
       executes the command string in global Q-reg q.
    b) A colon modified M command (:Mq) does not create a new set of 36
       local Q-regs, but rather keeps the current of local Q-regs active,
       and executes the command string in Q-reg q.
    c) Any M command that references a local Q-reg (M.q and/or :M.q) behaves
       like a colon modified M commmand; the current local Q-regs are used.
    In summary:
	 Mq	New set of local Q-regs
	:Mq	Current set of local Q-regs
	 M.q	Current set of local Q-regs
	:M.q	Current set of local Q-regs

8) FR command extensions
    The FR command now comes in the following forms:
    a) FRtext$
	Same as ^SDItext$, i.e., delete the preceeding last found search
	string, inserted text, etc. and replace it with "text".
    b) nFRtext$
	Same as nDItext$, i.e., delete the preceeding (n < 0) or following
	(n > 0) n characters and replace them with "text".
    c) m,nFRtext$
	Same as m,nKItext$, i.e., delete the characters spanned by m,n and
	replace them with "text".
    In all cases, the text buffer pointer is positioned immediately after
    "text" after the operation.

9) ^E flag handling
    Everytime text is read into the text buffer, the ^E (form feed) flag
    is set to -1, if the text read terminated due to a form feed, or 0,
    if the text read terminated elsewise.  The ^E flag can now also be
    set, e.g., 0^E and/or -1^E.  While any value can be set into the ^E
    flag, only the values 0 and -1 have any approved meaning.

10) Backing up during editing
    TECO can now move backwards as well as forwards in the file being
    edited.  This affects most file movement commands; the affect is
    that negative arguments now position backwards in the file in the
    obvious fashion.  Commands affected include:
    a) N and FN searches
	N and FN searches with negative arguments now proceed backwards
	through each text buffer and through the file being edited.  They
	terminate upon the correct search string match and/or beginning-of-
	file.  A colon modified N or FN command returns 0 at BOF.
    b) _ and E_ searches
	_ and E_ searches with negative arguments now proceed backwards
	through each text buffer and through the file being edited.  They
	terminate upon the correct search string match and/or BOF.  A colon
	modified _ or E_ command returns 0 at BOF.  _ searches are still
	subject to "Yank protection".  Remember that text file pages are
	DESTROYED by _ and E_ searches; there's no way to get them back!
    c) Y commands
	A -Y command will, subject to "Yank protection", DESTROY the current
	text buffer and bring in the previous page.  nY and -nY commands
	are still illegal; multiple yanks are done with n<Y> and n<-Y>.
	A colon modified -Y command return 0 at BOF.
    d) P commands
	A -P command will back up one page in the file begin edited.  A -nP
	command will back up n pages.  A colon modified -P or -nP command
	return 0 at BOF.  The command strings <:P;> and <-:P;> will take
	you to EOF or BOF, respectively.
    e) A commands
	The A command has many formats:
	 A	Append next page of text to current buffer
	 -A	Illegal (yields ?IAA, Illegal A arg)
	 :A	Append next page of text to current buffer; return -1 if
		something was appended, 0 otherwise
	 -:A	Illegal (yields ?IAA, Illegal A arg)
	 n:A	Append next n lines of text to current buffer; return -1
		if something was appended, 0 otherwise
	 -n:A	Illegal (yields ?IAA, Illegal A arg)
	 nA	Return value of character at (.+n); return -1 if (.+n) is
		outside of the text buffer [n can be + or -]

11) Null tags in O commands
    The indexed goto command (e.g., nOtag1,tag2,tag3$) will now allow
    null tags, e.g., nOtag1,tag2,,tag4,tag5$.  If the index selects the
    null tag then execution flows to the next sequential command.

12) Immediate mode commands
    Bit 32 in the ED flag enables immediate mode commands.  When immediate
    mode commands are enabled and the first character typed in response
    to TECO's * prompt is ESCape, TECO will read further characters decoding
    them as shown in the following table.  This gives TECO a simple method of
    decoding keyboard keys that generate ESCape sequences as immediate mode
    commands.  Each decoded keyboard key yields two values: the key's type
    code (in the range 0 through 3) and the key's value code (in the range
    0 through 127).  These values are passed to the TECO macro in Q-reg A
    by executing an effective <type>,<value>MA$$.  The macro in Q-reg A can
    be coded similiar to:
	UA				! Save the <value> code in A	!
	@O!TYPE0,TYPE1,TYPE2,TYPE3!	! Dispatch on <type> code	!
	!TYPE0!				! Type 0 codes come here	!
	QA@O!VAL0,VAL1,...
    a) Type 0 - ESCape followed by a control character
	The value code is the control character's code (0 through 31).
    b) Type 1 - ESCape followed by a letter (e.g., ESC, A)
		ESCape followed by [ then a letter (e.g., ESC, [, A)
		CSI    followed by a letter (e.g., CSI, A)
		ESCape followed by O then an uppercase letter (e.g., ESC, O, A)
		SS3    followed by an uppercase letter (e.g., SS3, A)
	The value code is the letter's character code trimmed to 5 bits
	(0 through 31).  Common keys of type 1 are:
	    Up arrow	Value = 1
	    Down arrow	Value = 2
	    Left arrow	Value = 4
	    Right arrow	Value = 3
	    PF1		Value = 16
	    PF2		Value = 17
	    PF3		Value = 18
	    PF4		Value = 19
	    ENTER	Value = 13
    c) Type 2 - ESCape followed by ? then a letter (e.g., ESC, ?, p)
		ESCape followed by O then a lowercase letter (e.g., ESC, O, p)
		SS3    followed by a lowercase letter (e.g., SS3, p)
	The value code is the letter's character code trimmed to 5 bits
	(0 through 31).  Common keys of type 2 are:
	    Keypad ,	Value = 12
	    Keypad -	Value = 13
	    Keypad .	Value = 14
	    Keypad 0	Value = 16
	    Keypad 1	Value = 17
	     ...	 ...
	    Keypad 8	Value = 24
	    Keypad 9	Value = 25
    d) Type 3 - ESCape followed by [ then a digit string then ~
		CSI    followed by a digit string then ~
	The value code is the digit string value (0 through 127).
	All of the LK201 keyboard's editing and function keys generate
	sequences of this format.

13) ^T command extensions
    The ^T command now comes in the following forms:
    a) ^T
	Read the next input character and return its value.
    b) n^T
	Print the character whose value is n.  n is used mod 256.
    c) :^T
	Read and decode the next input character; return its type code
	and value as follows (similiar to Immediate Commands above):
	    Type = 0	Normal character, value is character's value.
	    Type = 1	Control character (except ESCape, CSI, and SS3),
			value is control character's value.  A typed RETURN
			yields Type = 1, Value = 13 and a subsequent
			^T or :^T command does not return a LINE FEED.
	    Type = 2	Same as Immediate Commands type 0.
	    Type = 3	Same as Immediate Commands type 1.
	    Type = 4	Same as Immediate Commands type 2.
	    Type = 5	Same as Immediate Commands type 3.
    d) n:^T
	Print the character whose value is n in (one shot) binary output
	mode.  n is used mod 256.

14) n,1:W command
    The n,1:W command (change scope width) automatically informs the
    executive of your terminal's new width setting and automatically
    issues the appropriate sequence to physically change the terminal's
    screen mode (80 vs. 132 column mode) if needed.

VAX/VMS specific user visible differences TECO V36 to TECO V39:

1) ET bits
    a) 256 (truncate long lines)
	Truncate long lines now reflects and can change the state of the
	terminal characteristic WRAP/NOWRAP.  This bit is initially clear
	if the terminal is set to WRAP; it is initially set if the terminal
	is set to NOWRAP.  Changing the bit will cause the terminal to change
	its WRAP/NOWRAP characteristic.  TECO will restore the terminal to
	its original state upon exit.

2) ^T handling
    VMS's handling of ^T (one line status report) is automatically turned
    off by TECO if it ever asks the user for input.  The original state of
    ^T handling is restored upon exit.  MUNGed TECO macros that never ask
    the user for input do not affect VMS's ^T handling.

3) File record format/attribute handling
    Below is a complete list of valid TECO input file record format/attribute
    combinations and the resulting file record format/attribute combination
    for EB commands:
	     Input			    Output
	Format	Attribute		Format	Attribute
	 Fix	 none			 Var	 Implied
	 Fix	 Implied		 Var	 Implied
	 Fix	 FORTRAN		 Var	 FORTRAN
	 Var	 none			 Var	 Implied
	 Var	 Implied		 Var	 Implied
	 Var	 FORTRAN		 Var	 FORTRAN
	 VFC	 Print			 Var	 Implied
	 Stm	 none			 Stm	 Implied
	 Stm	 Implied		 Stm	 Implied

4) File specification qualifiers
    Below is a complete list of TECO's file specification qualifiers:
    a) Input processing
	/-CR	Force "none" file record attributes
	/CR	Force "Implied" file record attributes
	/FT	Force "FORTRAN" file record attributes
	/FTN	Same as /FT
	/B2	BASIC-PLUS-2 input processing (removes trailing &'s)
    b) Output processing
	/VAR	Create file record format "Var"
	/STM	Create file record format "Stm"
	/-CR	Create file record attribute "none"
	/CR	Create file record attribute "Implied"
	/FT	Create file record attribute "FORTRAN"
	/FTN	Same as /FT
	/NV	Ensure new version of file (always done for EBs)
	/B2	BASIC-PLUS-2 output processing (adds trailing &'s as needed)
    c) Open/create/access options
	/RW	Rewind before open/create
	/SH	Enable file sharing
	/SHR	Same as /SH

5) Help facility
    TECO has a builtin help facility.  This can be used in any of three ways:
    a) Issuing a HELP command from TECO's * prompt.  This HELP command obeys
       the standard VAX/VMS HELP command syntax rules.  The HELP commmand may
       be terminated by either RETURN or $$.
    b) Typing the / command immediately after an error.  TECO will respond
       with a one paragraph description of the error.
    c) Setting EH to 3.  This causes TECO to automatically respond with a
       one paragraph description of errors when they occur.

6) EDIT/TECO
    TECO has an official DCL interface; the command is EDIT/TECO.

Hacker visible differences TECO V36 to TECO V39:

1) CRTRUB handles multiple scope types
    CRTRUB (the scope type definition module) has been extended to handle
    up to 63 different scope types (the limit used to be 4).  Also, the
    format of this modules has changed.  Hackers with private CRTRUBs will
    need to re-code them...

2) n:W command values
    The n:W command values have been grouped to allow the addition of user
    controlled values.  0 <= n <= 255 is reserved for standard TECO usage.
    Of these, 0 through 7 are currently implemented; 8 through 255 are
    reserved and always return a zero.  256 <= n <= 32767 is for user
    usage.  There are two routines in CRTRUB that handle commands in this
    range: USRPRM for returning a value and USRSET for setting a new value.

	EDIT/TECO DCL command syntax summary

I've officially registered a DCL interface to TECO.

Please note that TECO on VAX/VMS will still continue to respond to the old
foreign command interface, viz:

	$ TECO :== $SYS$SYSTEM:TECO TECO
	$ MAKE :== $SYS$SYSTEM:TECO MAKE
	$ MUNG :== $SYS$SYSTEM:TECO MUNG """

as well as still responding to being simply run, viz:

	$ RUN SYS$SYSTEM:TECO

The new DCL syntax for TECO is as follows:

1) To invoke TECO to edit/create a file use

    EDIT/TECO [ qualifier(s) ] [ edit_file_spec ]

    (D)	/COMMAND		Set up from logical TEC$INIT, if any
	/COMMAND=ini_file_spec	Set up from file "ini_file_spec"
	/NOCOMMAND		No set up

    (D)	/CREATE			Create "edit_file_spec" if it doesn't exist
	/NOCREATE		Abort if "edit_file_spec" doesn't exist

    (D)	/MEMORY			Use TECO's memory logical TEC$MEMORY
	/NOMEMORY		Ignore TECO's memory logical TEC$MEMORY

	/OUTPUT=out_file_spec	Edit from "edit_file_spec" into "out_file_spec"
    (D)	/NOOUTPUT		Edit "edit_file_spec" to next higher version

	/READ_ONLY		Only read "edit_file_spec"
    (D)	/NOREAD_ONLY		Edit "edit_file_spec"

    If "edit_file_spec" is omitted then TECO will re-edit the file in its
    memory logical TEC$MEMORY or, if TEC$MEMORY doesn't exist or /NOMEMORY
    is specified, TECO will simply start up in command mode editing no file.

2) To invoke TECO to execute a TECO macro use

    EDIT/TECO/EXECUTE=cmd_file_spec [ qualifier(s) ] [ argument ]

    (D)	/COMMAND		Set up from logical TEC$INIT, if any
	/COMMAND=ini_file_spec	Set up from file "ini_file_spec"
	/NOCOMMAND		No set up

    (D)	/CREATE			Legal, but ignored...
	/NOCREATE		Legal, but ignored...

    (D)	/MEMORY			Legal, but ignored...
	/NOMEMORY		Legal, but ignored...

    "Cmd_file_spec" is executed as a TECO macro with "argument" placed
    in the text buffer.  "Cmd_file_spec" defaults to a file type of .TEC.
    "Argument" must be enclosed in double quotes if it contains any blanks
    and/or special characters.

    /[NO]CREATE and /[NO]MEMORY are legal, but ignored, so that DCL symbols
    like the following can be used with the /EXECUTE=cmd_file_spec qualifier:

	$ TECO :== EDIT/TECO/NOCREATE
	$ TECO :== EDIT/TECO/NOMEMORY
	$ TECO :== EDIT/TECO/NOCREATE/NOMEMORY
	VAX/VMS specific goodies in TECO

TECO has a built-in help facility.  There are three kinds of help:

	1) A built-in HELP command with the same syntax as the DCL HELP
	   command.

	2) A long form error message printer triggered by typing a slash
	   character (/) immediately after an error (just as an immediate
	   question mark character (?) re-prints the erring command line).

	3) Setting EH to 3 automatically prints the long form error
	   message upon errors.

The built-in HELP command can be used to get information about TECO or to
access any standard VAX/VMS HELP library.  It's format is

	HELP [[/LIBRARY]=[=]name] [key-1 [key-2 [...]]]

Using the =name parameter selects a HELP library other than the TECO
library.  The ==name format both selects the library for this HELP
command and makes it the default library for subsequent HELP commands.

For example

  HELP ==HELP SYSTEM $ASSIGN

would select the system HELP library, establish it as the default, and
tell you about the Assign I/O Channel system service.

The Key-n parameters obey the standard VAX/VMS HELP syntax rules.

The built-in HELP command is only available interactively from TECO's
main asterisk (*) prompt.  It is special cased and cannot be combined
with normal TECO commands.  The built-in HELP command can be terminated
by either RETURN or $$.

The following special features of VAX/VMS TECO were designed to allow it
to be a very flexible and powerful tool in building automated procedures.

Exit status code

	TECO's exit status code, as reflected by the DCL symbols $STATUS
	and $SEVERITY, can be examined to determine how TECO exited:

	 $STATUS    $SEVERITY	Exit reason

	%X00000001	1	Normal exit (EX, 3 CTRL/Z's, etc.)
	%X00000009	1	EG exit
	%X1000002C	4	Error exit (error with 128 set in ET)
	%X0???????     LBC	Fatal internal error exit

:EG command support

	The general form of a :EG command is

		:EGcmd args$

	:EG commands always return a value

		-1	for success
		 0	for 'cmd' not supported
	       other	for error code unique to the 'cmd'

	TECO supports all four of the standard :EG commands.  These
	commands are used by various operating system independent TECO
	macros.  All four commands operate in a similiar manner

	:EGxxx$		Reads the logical name into Q-register *.  If the
			logical name is undefined, Q-register * is set to
			the null string.

	:EGxxx $	Deletes (deassigns) the logical name.  This is a
			nooperation if the logical name is already undefined.

	:EGxxx text$	Creates (assigns) the logical name with an equivalence
			string of 'text'.  Any previous definition of the
			logical name is superseded.

	The four standard :EG commands and their corresponding logicals are

	INI	TEC$INIT	Used to find your private initializer
	LIB	TEC$LIBRARY	Used to find your TECO macro library
	MEM	TEC$MEMORY	Used to hold the last file you edited
	VTE	TEC$VTEDIT	Used to find your scope editing macro

	In addition to the above, TECO has a :EG command that lets
	you create DCL local symbols.  The format is this command is

	:EGSYM symbol_name symbol_value_string$

Combining the DCL symbol creation capability with the special EG exit status
code lets you do things like

	$ <Invoke TECO with a macro like the following>
		...
		:@EG/SYM FILE_NAME foobar/ EG$$
	$ IF $STATUS .NE. 9 THEN GOTO <Somewhere else>
	$ BLISS 'FILE_NAME'
	$ LINK 'FILE_NAME'