.FIGURE 15
.CENTER
TECO IN C FOR FREE
.SKIP 3
.CENTER
Pete Siemsen
.CENTER
645 Ohio Ave, _# 302
.CENTER
Long Beach, Ca. 90814
.PAGE
.FIGURE 5
	TECO-C is an implementation of TECO as defined by the PDP-11
Teco User's Guide,  DEC order number DEC-11-UTECA-B-D.  It was written
using the Guide as a specification.
.SKIP 8
.CENTER
Undocumented features of TECO-11 and TECO-C
.skip 3
.LIST
.LIST ELEMENT
8192 bit in ET flag causes ' character to be ESCAPE
.LIST ELEMENT
Q-registers named ".x" are local to the current macro level.
.LIST ELEMENT
HELP
.END LIST
.PAGE
.figure 1
.CENTER
TECO-C vs. TECO-11
.SKIP
.CENTER
in rough order of importance
.SKIP 4
.LITERAL
		TECO-C				TECO-11


	free:  you get what you		exhaustively tested
	pay for (maybe bugs)

	runs on MicroVaxes and		only compatibility mode
	more soon			(until VMS v5.0)

	No W command (no video)		supports slow video and
	and no /SCROLL qualifier	supports /SCROLL

	virtual memory buffer and	100k total bytes
	q-registers

	faster				slower

	UNIX-style command line,	VMS-style command line,
	not parsed with macro		parsed with a TECO macro

	32-bit numeric values		16-bit numeric values

	VT200s in VT200 mode		VT200s in VT100 mode if you
					want LF and BS immediate commands

	direct I/O to/from		not implemented
	q-registers (E% and EQ)

	large (not complete)		small help file,  can't
	HELP file,  interactive		move around help tree

	only TEC$HELP or system		settable HELP library
	help libraries

	EO returns 100			EO returns 39, 40, etc.

	correct case sensitivity	thinks { is same as [,  etc.

	no -P, -N, -Y			has -P, -N, -Y

	no filename switches		has them,  like /CR and /FT


.END LITERAL
.CENTER
other very minor differences
.PAGE
.CENTER
TECO-C portability
.LIST
.LIST ELEMENT
283 files,  32 are system-dependent
.LIST ELEMENT
Runs under VAX/VMS,  almost runs under XENIX,  once ran under CPM-68k
.LIST ELEMENT
Include file controls conditionally compiled code in system-dependent
files.
.LIST ELEMENT
Almost no terminal dependencies.
.LIST ELEMENT
Uses RMS under VMS,  fopen/fclose/fgets etc. under XENIX.
.LIST ELEMENT
Uses a memory move function which maps to OTS$MOVC3 under VMS and to
C code under XENIX.
.LIST ELEMENT
Reports errors from system-dependent code with detail dependent upon the
system.  For instance,  RMS error messages are reported from VAX code.
.LIST ELEMENT
Uses a UNIX-style command line and C's standard way of accessing
command-line arguments.
.END LIST
.PAGE
.CENTER
Implementation of TECO-C
.SKIP
.LIST
.LIST ELEMENT
Edit buffer gap scheme instead of a contiguous edit buffer.
.LIST ELEMENT
Commands are parsed by indexing into a jump table using the command character.
.LIST ELEMENT
Memory is managed with calloc/realloc/free calls.
.LIST ELEMENT
One function per file.
.LIST ELEMENT
Function names are 6 characters or less.
.LIST ELEMENT
Every function has access to global variables:  there is very little
parameter passing.
.LIST ELEMENT
System-dependent function names start with a "Z".
.LIST ELEMENT
An in-line debugging system exists which displays function entry/exit
text as TECO-C runs.  Can be controlled with _^P command and is
conditionally compiled.
.LIST ELEMENT
There is a small suite of TECO test macros.
They were written to compare TECO-C's behavior to TECO-11's.
.END LIST
.PAGE
.CENTER
Helpful files in TECO-C save set
.SKIP
.LIST
.LIST ELEMENT
TECOC.HLB is better than TECO-11's help library,  and can be used from
TECO-11.
.LIST ELEMENT
CHANGE.TEC is like VMS SEARCH,  but changes the string.
.LIST ELEMENT
There is no manual,  but COMMANDS.TXT contains a "wall chart" of TECO-C
commands.
.LIST ELEMENT
PG.MEM contains a "programmer's" guide which describes algorithms and
data structures used in TECO-C.
.LIST ELEMENT
PROBLEMS.TXT contains desciptions of known bugs and some ideas.
.LIST ELEMENT
Several (20-30) TECO macros can be found in files named *.TEC.  They are
undocumented.
.END LIST
.PAGE
.CENTER
Future of TECO-C
.SKIP
.LIST
.LIST ELEMENT
Video: what form?  TECO-11's VTEDIT.TEC is clunky.
Making it like EDT or TPU means depending on a DEC-style keyboard.
Making it like EMACS is REALLY re-inventing the wheel.
.LIST ELEMENT
Video: how to handle terminals?  If I use SMG,  the it's VAX-dependent.
If I use curses,  then it's UNIX-dependent.  If I write my own,  then it
will support a small number of terminals.
.LIST ELEMENT
Avoid enhancements that cause several "flavors" to exist, if possible.
.LIST ELEMENT
When it runs well under two environments,  TECO-C will be submitted to
the DECUS Software Library.  Other TECO-related elements of the library
will be combined into a single Library entry.
.END LIST