;
;   >>>>>>--  COMMAND LINE HISTORY PROCESSING FOR CP/M PLUS --<<<<<<
;
;	(C) Copyright 1986 by Michael D. Kersenbrock, 18625 S.W. Hennig
;	Court, Aloha, Oregon 97006  All rights Reserved.
;
;       Personal non-commercial use and distribution of this software
;	is permitted so long as the above Copyright notice is maintained
;	with this and subsequent copies.
;
;	History (no pun intended, but noted):
;
;		Version 1.0 - September 1986  Original release
;
;
;  This was written first in psuedo HLL code, then hand coded into assembly
;  language.  That psuedo-HLL code is included below as comment lines.
;
;Note: No matter how efficiently written, this isn't really practical without
;      a ramdisk or a fast hard disk.  No strong effort is done to minimize
;      the file size (and thus disk speed) because it isn't likely to 
;      acceptably fast with a floppy (regardless). I use a FAST 720K ramdisk.
;      Actually, I have tried it with my floppy, and it isn't too bad at all
;      but then, the floppy IS cache'd.  I did my own cacheing over and above
;      CP/M 3.0's (didn't like theirs), so I don't know how it works with
;      DRI's version of cache. I have 178K of floppy-file cacheing.
;
;      This history implements "!!", "!pattern", "!number" for command
;      substitution, and implements the command 'h' to give a list of 
;      previous commands and their numbers.
;
;      These examples use '!' as the history command character, this is
;      the same as Berkeley-UNIX's (tm of AT&T) CSH shell.  This CP/M
;      implementation uses '|' interchangeably.  The functions implemented
;      are:
;
;		!!    		Repeat last command, similar to ^W
;
;		!<pattern>	Repeat last command that starts with
;				the given pattern.
;
;		!<number>	Repeat command numbered <number>
;
;				EACH OF THE ABOVE THREE: append the rest of
;				"this line" to the substituted line. Example:
;
;				   If command #40 were: "COMPILE -O -C", then
;				   "!40 ROUTINE.C" would result in:
;				   "COMPILE -O -C ROUTINE.C"
;
;		h		Command that gives numbered command history 
;				list to be used with the above command.
;
;	When a history-substitution is made for a command, the new
;	command line is presented to the console for editing in a
;	similar fashion to the banked-^W command (unlike csh).
;
;	With the substitutions, the rest of the calling command line
;	(if any) is added onto the substitution-replacement line.
;
;	If you don't want submit files to store their internal-commands
;	into the history record, put a space in front of those commands.
;
;	If the file "<tempdisk>: CCP.EXT" exists, then that program is
;	loaded into memory at address 6000H, then executed with HBUFFER 
;	and CMDLINE address-pointers passed on the stack "above" the
;       return address. CMDLINE's pointer is "just" above the return address.
;
;
;	Data structure "buffer" has 42 CMDSIZE-byte records numbered 0-41.
;
;		defns: when file is read in, 
;				record 1: contains the last command number
;				record 2: contains the last command
;			then...
;				record 0: is where last command nr is moved to
;				record 1: is where "translated" current command
;					  is built.
;	
;		
;History file format:
;
;		One command line per RECSIZE byte logical record.
;
;		First sector contains the current command number (1-byte)
;
;		Second sector contains the last command 
;		Third sector contains the command before last 
;				(etc.)
;
;		If the first byte of a sector is a null, we have
;		"reached the end" of the history (null-commands are
;		not stored).
;
;		The file saves the last 40 command lines.
;
;		A "command-line" has the first byte being the byte count,
;		and a null-terminator just after the last "real" byte.
;
;	        If a substituted command line is modified by the line
;	  	editor (when given the opportunity), then this new changed
;		version will be put into the history along with the one
;		"fetched" from history.
;
; Pattern: String of non-space and non-control characters
;
;
;
; This history routine is called with a newly gotten command in the
; CMDLINE buffer.  This routine will play games with the buffer (possibly
; modifying its contents), then return.
;
;	if (Command length == 0 || cmd starts w/' ' or ':') {
;		return();
;	}
;	buffer is cleared to nulls
;	Check to see if "temp:Historyx.dat" exists
;
;	if (exists) {
;		readfile into data buffer starting at record-1 point
;	}
;
;	read command number from record-1, and write it to record-0 
;	reset substitution and error flags;
;	if (first-char == '!') {
;		if (2nd char == '!') {
;			copy line at record-2 to record-1;
;			copy rest of cmdline onto end of the record-1 line;
;			set substitution flag;
;		}
;		else if (rest up to a terminator is numeric) {
;			translate number to binary;
;			if ( command number wanted is NOT in our list ) {
;				clear cmd line
;				print "not found"
;				set errorflag;
;				break out from first level 'if'
;			}
;			else {
;				copy record[(cmdnr-number+1)] to record-1;
;			copy rest of cmdline onto end of the record-1 line;
;				set substitution flag;
;			}
;		}
;		else {
;			search (bottom-up) for a string match (no white space)
;			if (found) {
;				copy that line to record-1;
;				copy rest of cmd line onto end of record-1 line
;				set substitution flag;
;			}
;			else {	
;				clear cmd line
;				print "not found"
;				set errorflag;
;				break out from first level 'if'
;			}
;		}
;		copy record-1 to cmdline;
;
;	}
;	else if (1st char == 'h' && 2rd char == terminator) {
;		reset substitution flag, and set err flag
;		print cmd lines w/numbers to screen
;	}
;	else {
;		copy cmdline to record-1
;	}
;	if (not ERRORFLAG) {
;		increment command number at 0 ;
;		if (first-char-of-cmd is printable, and not ' ' or ':') {
;			write buffer starting at record0 (bumps last one out)
;		}
;	}
;	else {
;		reset command line;
;	}
;
;	if (substitution flag set) {
;		calculate checksum of cmdline;
;		set DMA address to cmdline;
;		set DE to zero and call function 10 (edit substitution line);
;		if (new checksum != old checksum) {
;			go through self again;
;		}
;	}
;
;	command line now contains command line, ready for "normal" processing.
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