;
; Program: ERROR2
; Author: Richard Conn
; Version: 1.0
; Date: 5 Mar 84
;
version	equ	10

;
;	This error handler displays the error line to the user and
; provides him with four options as to how to process this line:
;		1. Replace the command in error with a new command
;		2. Skip the command in error and resume execution
;			with the next command
;		3. Replace the command line as it now stands
;		4. Throw away the command line and resume user
;			control
;
;	Unlike ERROR1, ERROR2 is screen-oriented, using the Z3TCAP
; for support.
;
;	This program is transportable from one ZCPR3 system to another
; provided it is reassembled with the correct address for the ZCPR3
; Environment Descriptor (Z3ENV) or DDT is used to patch this address
; (which is the first two bytes after the opening JMP).  If an external
; ZCPR3 Environment Descriptor is not available, one will have to be
; provided by setting the Z3ENV equate to 0 and providing SYSENV.LIB in
; the current directory at assembly time.
;

;
; Equates for Key Values
;
z3env	SET	0f400h	;address of ZCPR3 environment
cmtch	equ	';'	;comment character
cr	equ	0dh
lf	equ	0ah

;
; External Z3LIB and SYSLIB Routines
;
	ext	z3vinit
	ext	print,pstr,codend,capine,bbline,crlf,moveb
	ext	erradr,puter1,puterc		;Error Handler Routines
	ext	qprint				;Quiet Mode Prints
	ext	getenv,getefcb,getcl1,qerror	;Z3 Messages et al
	ext	at,cls,stndout,stndend,gotoxy,vprint,gxymsg	;VLIB Routines

;
; Environment Definition
;
	if	z3env ne 0
;
; External ZCPR3 Environment Descriptor
;
	jmp	start
	db	'Z3ENV'	;This is a ZCPR3 Utility
	db	1	;External Environment Descriptor
z3eadr:
	dw	z3env
start:
	lhld	z3eadr	;pt to ZCPR3 environment
;
	else
;
; Internal ZCPR3 Environment Descriptor
;
	MACLIB	Z3BASE.LIB
	MACLIB	SYSENV.LIB
z3eadr:
	jmp	start
	SYSENV
start:
	lxi	h,z3eadr	;pt to ZCPR3 environment
	endif

;
; Start of Program -- Initialize ZCPR3 Environment
;
	call	z3vinit	;initialize the ZCPR3 Environment
;
; Print Banner
;
	call	qprint
	db	'ERROR2, Version '
	db	(version/10)+'0','.',(version mod 10)+'0'
	db	cr,lf,0
;
; Determine if Program Invoked as an Error Handler or By the User
;
	call	qerror	;error?
	jz	handler	;handle error
;
; Invoked by the User, so Install as an Error Handler
;
	call	getenv		;must have a Z3TCAP entry
	lxi	d,80h		;pt to Z3TCAP
	dad	d
	mov	a,m		;must not be space or less
	cpi	' '+1
	jnc	start0
	call	print
	db	cr,lf,' No Z3TCAP - Aborting',0
	ret
;
; Determine Name of Routine
;
start0:
	call	getefcb		;pt to external FCB
	jz	start1		;proceed if external FCB not available
;
; Make Name Invoked by User the Name of the Error Handler
;
	inx	h		;pt to first char
	lxi	d,ername	;pt to name of error handler message
	mvi	b,8		;at most 8 bytes
	call	moveb		;copy into buffer
;
; Make Command Line in Buffer the Error Handler
;
start1:
	lxi	h,ername	;make name in buffer the error handler
	call	puterc		;set command
	mvi	a,0ffh		;set error code
	call	puter1		;set message
	call	print
	db	' Error Handler Installed',0
	ret
;
; Handle Error
;
handler:
	call	erradr		;get address of error line
	xchg			;HL pts to free area, DE pts to error line
	call	codend		;get ptr to free area
	shld	badcmd		;save ptr to bad command
;
; Extract Bad Command and Store It in Memory Starting at BADCMD
;	DE pts to bad command, HL pts to location to store it at
;
savebad:
	ldax	d		;get next char
	mov	m,a		;put it
	ora	a		;done?
	jz	sbad1
	cpi	cmtch		;check for comment
	jz	sbad1
	inx	h		;pt to next
	inx	d
	jmp	savebad
;
; Set ending 0 in bad command buffer and check for continuation
;
sbad1:
	mvi	m,0		;store ending zero
	inx	h		;pt to next
	cpi	cmtch		;more?
	jnz	sbad2
	inx	d		;pt to rest of command
sbad2:
	shld	restcmd		;save rest of command line
;
; Extract Rest of Command Line and Store It in Memory Starting at RESTCMD
;
saverest:
	ldax	d		;get next
	mov	m,a		;put it
	inx	h		;pt to next
	inx	d
	ora	a		;done?
	jnz	saverest
	shld	scratch		;save ptr to scratch area
;
; Prompt User for Action
;
prompt:
	call	cls	;clear screen
	call	gxymsg
	db	3,22
	db	'>>>> ',1,'VIDEO ERROR HANDLER',2,' <<<<',0
	call	gxymsg
	db	5,28
	db	'-- Error  Line --',0
	call	at
	db	6,10
	call	stndout	;reverse video
	call	erradr		;get address of error line
	call	pstr
	call	stndend	;normal video
	mvi	h,10	;position cursor
	mvi	l,15
	shld	infoxy
	call	gxymsg
	db	8,30
	db	'-- Options --',0
	call	atinfo
	call	vprint
	db	'1. Replace Command in Error with a New Command',0
	call	atinfo
	call	vprint
	db	'   Replace ',1,0
	lhld	badcmd
	call	pstr
	call	atinfo
	call	atinfo
	call	vprint
	db	2,'2. Advance to Next Command and Resume Processing',0
	call	atinfo
	call	vprint
	db	'   Advance to ',1,0
	lhld	restcmd
	call	pstr
	call	atinfo
	call	atinfo
	call	vprint
	db	2,'3. Replace Entire Line with a New Line',0
	call	atinfo
	call	vprint
	db	'   Replace ',1,0
	call	erradr		;pt to error line
	call	pstr
	call	atinfo
	call	atinfo
	call	vprint
	db	2,'4. Throw Away Entire Line and Continue',0
	call	atinfo
	call	vprint
	db	'   Throw Away ',1,0
	call	erradr		;pt to error line
	call	pstr
	call	stndend
userin:
	call	gxymsg
	db	22,20
	db	'Select Option - ',0
	call	capine
	cpi	'1'	;option 1
	jz	replace	;replace command in error
	cpi	'2'	;option 2
	jz	advance	;advance to next command
	cpi	'3'	;option 3
	jz	newline	;enter new line
	cpi	'4'	;option 4
	jz	flush	;throw away line
	call	print
	db	8,'  Invalid Option - Retry',0	;backspace over error
	jmp	userin
;
; Position at INFOXY and advance ptr to next line
;
atinfo:
	lhld	infoxy	;pt to next position
	call	gotoxy	;go there
	inr	h	;next line
	shld	infoxy
	ret
;
; Replace Command in Error
;
replace:
	call	print
	db	'   Replacement Command?',cr,lf,'  ',0
	lhld	restcmd	;pt to rest of command line in DE
	xchg
	mvi	a,0ffh	;capitalize
	call	bbline	;get line from user
	call	build	;build and run command
	jmp	prompt	;continue if error
;
; Advance to Rest of Command Line
;
advance:
	lhld	restcmd	;pt to it
	xchg
	lxi	h,empty	;HL pts to empty command, DE pts to tail
	call	build	;build and run command
	jmp	prompt	;continue if error
;
; Enter New Line
;
newline:
	call	print
	db	'   New Command?',cr,lf,'  ',0
	mvi	a,0ffh	;capitalize
	call	bbline	;get line from user
	lxi	d,empty	;HL pts to user command, DE pts to empty command
	call	build	;build and run command
	jmp	prompt	;continue if error
;
; Flush Commands
;
flush:
	ret		;simply exit if no more commands
;
; Build New Command Line in SCRATCH Area and Run it by returning to ZCPR3
;   On input, HL pts to header, DE pts to tail
;
build:
	lxi	b,1	;set char count (1 for ending zero)
	push	d	;save ptr to tail
	push	h	;save ptr to header
	lhld	scratch	;pt to scratch area
	pop	d	;get ptr to header
	ldax	d	;get first char
	ora	a	;any there?
	cnz	copy	;copy line into buffer
	pop	d	;get ptr to tail
	ldax	d	;anything there?
	ora	a
	jz	bldt	;terminate build if not
	mvi	m,cmtch	;begin with semicolon
	inx	h	;pt to next
	call	copy
bldt:
	mvi	m,0	;store ending zero
;
; Store Command Line into MCL Buffer
;
	call	getcl1	;pt to command line
	cmp	c	;check for char count within range
	rc
	mov	a,b	;check for line too long
	ora	a	;line too long?
	rnz		;error if so
	lxi	d,4	;pt to first char
	push	h	;save ptr to current
	dad	d
	pop	d	;get ptr to current
	xchg		;DE pts to first char position, HL pts to CL buffer
	mov	m,e	;set address to resume processing
	inx	h
	mov	m,d
	lhld	scratch		;pt to new line
	xchg			;in DE, while HL pts to first char position
	call	copy		;copy it
	mov	m,a		;store ending zero
	pop	d		;clear stack
	ret			;resume processing
;
; Copy string pted to by DE into buffer pted to by HL
;
copy:
	ldax	d	;get next char
	ora	a	;done?
	rz
	mov	m,a	;store it
	inx	b	;increment count
	inx	h	;pt to next
	inx	d
	jmp	copy
;
; Buffers
;
ername:
	db	'ERROR2  ',0	;name of error handler
empty:
	db	0	;empty command line
infoxy:
	ds	2	;xy-coordinate for display
badcmd:
	ds	2	;ptr to bad command extracted
restcmd:
	ds	2	;ptr to tail of bad command line
scratch:
	ds	2	;ptr to scratch area used to build new lines

	end