File:  [gforth] / gforth / Attic / kernel.fs
Revision 1.3: download - view: text, annotated - select for diffs
Tue Sep 24 19:15:03 1996 UTC (22 years, 8 months ago) by pazsan
Branches: MAIN
CVS tags: HEAD
Some bug fixing:
\G in cross compilation works now
marker <-> local conflict resolved
hack around problems with non-relocating images.

\ kernel.fs    GForth kernel                        17dec92py

\ Copyright (C) 1995 Free Software Foundation, Inc.

\ This file is part of Gforth.

\ Gforth is free software; you can redistribute it and/or
\ modify it under the terms of the GNU General Public License
\ as published by the Free Software Foundation; either version 2
\ of the License, or (at your option) any later version.

\ This program is distributed in the hope that it will be useful,
\ but WITHOUT ANY WARRANTY; without even the implied warranty of
\ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
\ GNU General Public License for more details.

\ You should have received a copy of the GNU General Public License
\ along with this program; if not, write to the Free Software
\ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

\ Idea and implementation: Bernd Paysan (py)

\ Log:  ', '- usw. durch [char] ... ersetzt
\       man sollte die unterschiedlichen zahlensysteme
\       mit $ und & zumindest im interpreter weglassen
\       schon erledigt!
\       11may93jaw
\ name>         0= nicht vorhanden              17may93jaw
\               nfa can be lfa or nfa!
\ find          splited into find and (find)
\               (find) for later use            17may93jaw
\ search        replaced by lookup because
\               it is a word of the string wordset
\                                               20may93jaw
\ postpone      added immediate                 21may93jaw
\ to            added immediate                 07jun93jaw
\ cfa, header   put "here lastcfa !" in
\               cfa, this is more logical
\               and noname: works wothout
\               extra "here lastcfa !"          08jun93jaw
\ (parse-white) thrown out
\ refill        added outer trick
\               to show there is something
\               going on                        09jun93jaw
\ leave ?leave  somebody forgot UNLOOP!!!       09jun93jaw
\ leave ?leave  unloop thrown out
\               unloop after loop is used       10jun93jaw

HEX

\ labels for some code addresses

: docon: ( -- addr )	\ gforth
    \G the code address of a @code{CONSTANT}
    ['] bl >code-address ;

: docol: ( -- addr )	\ gforth
    \G the code address of a colon definition
    ['] docon: >code-address ;

: dovar: ( -- addr )	\ gforth
    \G the code address of a @code{CREATE}d word
    ['] udp >code-address ;

: douser: ( -- addr )	\ gforth
    \G the code address of a @code{USER} variable
    ['] s0 >code-address ;

: dodefer: ( -- addr )	\ gforth
    \G the code address of a @code{defer}ed word
    ['] source >code-address ;

: dofield: ( -- addr )	\ gforth
    \G the code address of a @code{field}
    ['] reveal-method >code-address ;

NIL AConstant NIL \ gforth

\ Bit string manipulation                              06oct92py

\ Create bits  80 c, 40 c, 20 c, 10 c, 8 c, 4 c, 2 c, 1 c,
\ DOES> ( n -- )  + c@ ;

\ : >bit  ( addr n -- c-addr mask )  8 /mod rot + swap bits ;
\ : +bit  ( addr n -- )  >bit over c@ or swap c! ;

\ : relinfo ( -- addr )  forthstart dup @ + !!bug!! ;
\ : >rel  ( addr -- n )  forthstart - ;
\ : relon ( addr -- )  relinfo swap >rel cell / +bit ;

\ here allot , c, A,                                   17dec92py

: dp	( -- addr ) \ gforth
    dpp @ ;
: here  ( -- here ) \ core
    dp @ ;
: allot ( n -- ) \ core
    dp +! ;
: c,    ( c -- ) \ core
    here 1 chars allot c! ;
: ,     ( x -- ) \ core
    here cell allot  ! ;
: 2,	( w1 w2 -- ) \ gforth
    here 2 cells allot 2! ;

\ : aligned ( addr -- addr' ) \ core
\     [ cell 1- ] Literal + [ -1 cells ] Literal and ;
: align ( -- ) \ core
    here dup aligned swap ?DO  bl c,  LOOP ;

\ : faligned ( addr -- f-addr ) \ float
\     [ 1 floats 1- ] Literal + [ -1 floats ] Literal and ;

: falign ( -- ) \ float
    here dup faligned swap
    ?DO
	bl c,
    LOOP ;

\ !! this is machine-dependent, but works on all but the strangest machines
' faligned Alias maxaligned ( addr1 -- addr2 ) \ gforth
' falign Alias maxalign ( -- ) \ gforth

\ !! machine-dependent and won't work if "0 >body" <> "0 >body maxaligned"
' maxaligned Alias cfaligned ( addr1 -- addr2 ) \ gforth
\ the code field is aligned if its body is maxaligned
' maxalign Alias cfalign ( -- ) \ gforth

: chars ( n1 -- n2 ) \ core
; immediate


\ : A!    ( addr1 addr2 -- ) \ gforth
\    dup relon ! ;
\ : A,    ( addr -- ) \ gforth
\    here cell allot A! ;
' ! alias A! ( addr1 addr2 -- ) \ gforth
' , alias A, ( addr -- ) \ gforth 


\ on off                                               23feb93py

: on  ( addr -- ) \ gforth
    true  swap ! ;
: off ( addr -- ) \ gforth
    false swap ! ;

\ dabs roll                                           17may93jaw

: dabs ( d1 -- d2 ) \ double
    dup 0< IF dnegate THEN ;

: roll  ( x0 x1 .. xn n -- x1 .. xn x0 ) \ core-ext
  dup 1+ pick >r
  cells sp@ cell+ dup cell+ rot move drop r> ;

\ name> found                                          17dec92py

$80 constant alias-mask \ set when the word is not an alias!
$40 constant immediate-mask
$20 constant restrict-mask

: ((name>))  ( nfa -- cfa )
    name>string +  cfaligned ;

: (name>x) ( nfa -- cfa b )
    \ cfa is an intermediate cfa and b is the flags byte of nfa
    dup ((name>))
    swap cell+ c@ dup alias-mask and 0=
    IF
	swap @ swap
    THEN ;

\ place bounds                                         13feb93py

: place  ( addr len to -- ) \ gforth
    over >r  rot over 1+  r> move c! ;
: bounds ( beg count -- end beg ) \ gforth
    over + swap ;

: save-mem	( addr1 u -- addr2 u ) \ gforth
    \ copy a memory block into a newly allocated region in the heap
    swap >r
    dup allocate throw
    swap 2dup r> -rot move ;

: extend-mem	( addr1 u1 u -- addr addr2 u2 )
    \ extend memory block allocated from the heap by u aus
    \ the (possibly reallocated piece is addr2 u2, the extension is at addr
    over >r + dup >r resize throw
    r> over r> + -rot ;

\ input stream primitives                              23feb93py

: tib ( -- c-addr ) \ core-ext
    \ obsolescent
    >tib @ ;
Defer source ( -- addr count ) \ core
\ used by dodefer:, must be defer
: (source) ( -- addr count )
    tib #tib @ ;
' (source) IS source

\ (word)                                               22feb93py

: scan   ( addr1 n1 char -- addr2 n2 ) \ gforth
    \ skip all characters not equal to char
    >r
    BEGIN
	dup
    WHILE
	over c@ r@ <>
    WHILE
	1 /string
    REPEAT  THEN
    rdrop ;
: skip   ( addr1 n1 char -- addr2 n2 ) \ gforth
    \ skip all characters equal to char
    >r
    BEGIN
	dup
    WHILE
	over c@ r@  =
    WHILE
	1 /string
    REPEAT  THEN
    rdrop ;

: (word) ( addr1 n1 char -- addr2 n2 )
  dup >r skip 2dup r> scan  nip - ;

\ (word) should fold white spaces
\ this is what (parse-white) does

\ word parse                                           23feb93py

: parse-word  ( char -- addr len ) \ gforth
  source 2dup >r >r >in @ over min /string
  rot dup bl = IF  drop (parse-white)  ELSE  (word)  THEN
  2dup + r> - 1+ r> min >in ! ;
: word   ( char -- addr ) \ core
  parse-word here place  bl here count + c!  here ;

: parse    ( char -- addr len ) \ core-ext
  >r  source  >in @ over min /string  over  swap r>  scan >r
  over - dup r> IF 1+ THEN  >in +! ;

\ name                                                 13feb93py

: capitalize ( addr len -- addr len ) \ gforth
  2dup chars chars bounds
  ?DO  I c@ toupper I c! 1 chars +LOOP ;
: (name) ( -- c-addr count )
    source 2dup >r >r >in @ /string (parse-white)
    2dup + r> - 1+ r> min >in ! ;
\    name count ;

: name-too-short? ( c-addr u -- c-addr u )
    dup 0= -&16 and throw ;

: name-too-long? ( c-addr u -- c-addr u )
    dup $1F u> -&19 and throw ;

\ Literal                                              17dec92py

: Literal  ( compilation n -- ; run-time -- n ) \ core
    postpone lit  , ; immediate restrict
: ALiteral ( compilation addr -- ; run-time -- addr ) \ gforth
    postpone lit A, ; immediate restrict

: char   ( 'char' -- n ) \ core
    bl word char+ c@ ;
: [char] ( compilation 'char' -- ; run-time -- n )
    char postpone Literal ; immediate restrict

: (compile) ( -- ) \ gforth
    r> dup cell+ >r @ compile, ;

\ not the most efficient implementation of POSTPONE, but simple
: POSTPONE ( -- ) \ core
    COMP' swap POSTPONE aliteral compile, ; immediate restrict

: interpret/compile: ( interp-xt comp-xt "name" -- ) \ gforth
    Create immediate swap A, A,
DOES>
    abort" executed primary cfa of an interpret/compile: word" ;
\    state @ IF  cell+  THEN  perform ;

\ Use (compile) for the old behavior of compile!

\ digit?                                               17dec92py

: digit?   ( char -- digit true/ false ) \ gforth
  base @ $100 =
  IF
    true EXIT
  THEN
  toupper [char] 0 - dup 9 u> IF
    [ 'A '9 1 + -  ] literal -
    dup 9 u<= IF
      drop false EXIT
    THEN
  THEN
  dup base @ u>= IF
    drop false EXIT
  THEN
  true ;

: accumulate ( +d0 addr digit - +d1 addr )
  swap >r swap  base @  um* drop rot  base @  um* d+ r> ;

: >number ( d addr count -- d addr count ) \ core
    0
    ?DO
	count digit?
    WHILE
	accumulate
    LOOP
        0
    ELSE
	1- I' I -
	UNLOOP
    THEN ;

\ number? number                                       23feb93py

Create bases   10 ,   2 ,   A , 100 ,
\              16     2    10   character
\ !! this saving and restoring base is an abomination! - anton
: getbase ( addr u -- addr' u' )
    over c@ [char] $ - dup 4 u<
    IF
	cells bases + @ base ! 1 /string
    ELSE
	drop
    THEN ;
: s>number ( addr len -- d )
    base @ >r  dpl on
    over c@ '- =  dup >r
    IF
	1 /string
    THEN
    getbase  dpl on  0 0 2swap
    BEGIN
	dup >r >number dup
    WHILE
	dup r> -
    WHILE
	dup dpl ! over c@ [char] . =
    WHILE
	1 /string
    REPEAT  THEN
        2drop rdrop dpl off
    ELSE
	2drop rdrop r>
	IF
	    dnegate
	THEN
    THEN
    r> base ! ;

: snumber? ( c-addr u -- 0 / n -1 / d 0> )
    s>number dpl @ 0=
    IF
	2drop false  EXIT
    THEN
    dpl @ dup 0> 0= IF
	nip
    THEN ;
: number? ( string -- string 0 / n -1 / d 0> )
    dup >r count snumber? dup if
	rdrop
    else
	r> swap
    then ;
: s>d ( n -- d ) \ core		s-to-d
    dup 0< ;
: number ( string -- d )
    number? ?dup 0= abort" ?"  0<
    IF
	s>d
    THEN ;

\ space spaces ud/mod                                  21mar93py
decimal
Create spaces ( u -- ) \ core
bl 80 times \ times from target compiler! 11may93jaw
DOES>   ( u -- )
    swap
    0 max 0 ?DO  I' I - &80 min 2dup type  +LOOP  drop ;
Create backspaces
08 80 times \ times from target compiler! 11may93jaw
DOES>   ( u -- )
    swap
    0 max 0 ?DO  I' I - &80 min 2dup type  +LOOP  drop ;
hex
: space ( -- ) \ core
    1 spaces ;

: ud/mod ( ud1 u2 -- urem udquot ) \ gforth
    >r 0 r@ um/mod r> swap >r
    um/mod r> ;

: pad    ( -- addr ) \ core-ext
  here [ $20 8 2* cells + 2 + cell+ ] Literal + aligned ;

\ hold <# #> sign # #s                                 25jan92py

: hold    ( char -- ) \ core
    pad cell - -1 chars over +! @ c! ;

: <# ( -- ) \ core	less-number-sign
    pad cell - dup ! ;

: #>      ( xd -- addr u ) \ core	number-sign-greater
    2drop pad cell - dup @ tuck - ;

: sign    ( n -- ) \ core
    0< IF  [char] - hold  THEN ;

: #       ( ud1 -- ud2 ) \ core		number-sign
    base @ 2 max ud/mod rot 9 over <
    IF
	[ char A char 9 - 1- ] Literal +
    THEN
    [char] 0 + hold ;

: #s      ( +d -- 0 0 ) \ core	number-sign-s
    BEGIN
	# 2dup d0=
    UNTIL ;

\ print numbers                                        07jun92py

: d.r ( d n -- ) \ double	d-dot-r
    >r tuck  dabs  <# #s  rot sign #>
    r> over - spaces  type ;

: ud.r ( ud n -- ) \ gforth	u-d-dot-r
    >r <# #s #> r> over - spaces type ;

: .r ( n1 n2 -- ) \ core-ext	dot-r
    >r s>d r> d.r ;
: u.r ( u n -- )  \ core-ext	u-dot-r
    0 swap ud.r ;

: d. ( d -- ) \ double	d-dot
    0 d.r space ;
: ud. ( ud -- ) \ gforth	u-d-dot
    0 ud.r space ;

: . ( n -- ) \ core	dot
    s>d d. ;
: u. ( u -- ) \ core	u-dot
    0 ud. ;

\ catch throw                                          23feb93py
\ bounce                                                08jun93jaw

\ !! allow the user to add rollback actions    anton
\ !! use a separate exception stack?           anton

: lp@ ( -- addr ) \ gforth	l-p-fetch
 laddr# [ 0 , ] ;

: catch ( x1 .. xn xt -- y1 .. ym 0 / z1 .. zn error ) \ exception
    sp@ >r
    fp@ >r
    lp@ >r
    handler @ >r
    rp@ handler !
    execute
    r> handler ! rdrop rdrop rdrop 0 ;

: throw ( y1 .. ym error/0 -- y1 .. ym / z1 .. zn error ) \ exception
    ?DUP IF
	[ here 9 cells ! ] \ entry point for signal handler
	handler @ dup 0= IF
	    2 (bye)
	THEN
	rp!
	r> handler !
	r> lp!
	r> fp!
	r> swap >r sp! drop r>
    THEN ;

\ Bouncing is very fine,
\ programming without wasting time...   jaw
: bounce ( y1 .. ym error/0 -- y1 .. ym error / y1 .. ym ) \ gforth
\ a throw without data or fp stack restauration
  ?DUP IF
      handler @ rp!
      r> handler !
      r> lp!
      rdrop
      rdrop
  THEN ;

\ ?stack                                               23feb93py

: ?stack ( ?? -- ?? ) \ gforth
    sp@ s0 @ > IF    -4 throw  THEN
    fp@ f0 @ > IF  -&45 throw  THEN  ;
\ ?stack should be code -- it touches an empty stack!

\ interpret                                            10mar92py

Defer parser
Defer name ( -- c-addr count ) \ gforth
\ get the next word from the input buffer
' (name) IS name
Defer compiler-notfound ( c-addr count -- )
Defer interpreter-notfound ( c-addr count -- )

: no.extensions  ( addr u -- )
    2drop -&13 bounce ;
' no.extensions IS compiler-notfound
' no.extensions IS interpreter-notfound

: compile-only-error ( ... -- )
    -&14 throw ;

: interpret ( ?? -- ?? ) \ gforth
    \ interpret/compile the (rest of the) input buffer
    BEGIN
	?stack name dup
    WHILE
	parser
    REPEAT
    2drop ;

\ interpreter compiler                                 30apr92py

\ not the most efficient implementations of interpreter and compiler
: interpreter ( c-addr u -- ) 
    2dup find-name dup
    if
	nip nip name>int execute
    else
	drop
	2dup 2>r snumber?
	IF
	    2rdrop
	ELSE
	    2r> interpreter-notfound
	THEN
    then ;

: compiler ( c-addr u -- )
    2dup find-name dup
    if ( c-addr u nfa )
	nip nip name>comp execute
    else
	drop
	2dup snumber? dup
	IF
	    0>
	    IF
		swap postpone Literal
	    THEN
	    postpone Literal
	    2drop
	ELSE
	    drop compiler-notfound
	THEN
    then ;

' interpreter  IS  parser

: [ ( -- ) \ core	left-bracket
    ['] interpreter  IS parser state off ; immediate
: ] ( -- ) \ core	right-bracket
    ['] compiler     IS parser state on  ;

here 0 , \ just a dummy, the real value of locals-list is patched into it in glocals.fs
AConstant locals-list \ acts like a variable that contains
		      \ a linear list of locals names


variable dead-code \ true if normal code at "here" would be dead
variable backedge-locals
    \ contains the locals list that BEGIN will assume to be live on
    \ the back edge if the BEGIN is unreachable from above. Set by
    \ ASSUME-LIVE, reset by UNREACHABLE.

: UNREACHABLE ( -- ) \ gforth
    \ declares the current point of execution as unreachable
    dead-code on
    0 backedge-locals ! ; immediate

: ASSUME-LIVE ( orig -- orig ) \ gforth
    \ used immediatly before a BEGIN that is not reachable from
    \ above.  causes the BEGIN to assume that the same locals are live
    \ as at the orig point
    dup orig?
    2 pick backedge-locals ! ; immediate
    
\ Control Flow Stack
\ orig, etc. have the following structure:
\ type ( defstart, live-orig, dead-orig, dest, do-dest, scopestart) ( TOS )
\ address (of the branch or the instruction to be branched to) (second)
\ locals-list (valid at address) (third)

\ types
0 constant defstart
1 constant live-orig
2 constant dead-orig
3 constant dest \ the loopback branch is always assumed live
4 constant do-dest
5 constant scopestart

: def? ( n -- )
    defstart <> abort" unstructured " ;

: orig? ( n -- )
 dup live-orig <> swap dead-orig <> and abort" expected orig " ;

: dest? ( n -- )
 dest <> abort" expected dest " ;

: do-dest? ( n -- )
 do-dest <> abort" expected do-dest " ;

: scope? ( n -- )
 scopestart <> abort" expected scope " ;

: non-orig? ( n -- )
 dest scopestart 1+ within 0= abort" expected dest, do-dest or scope" ;

: cs-item? ( n -- )
 live-orig scopestart 1+ within 0= abort" expected control flow stack item" ;

3 constant cs-item-size

: CS-PICK ( ... u -- ... destu ) \ tools-ext
 1+ cs-item-size * 1- >r
 r@ pick  r@ pick  r@ pick
 rdrop
 dup non-orig? ;

: CS-ROLL ( destu/origu .. dest0/orig0 u -- .. dest0/orig0 destu/origu ) \ tools-ext
 1+ cs-item-size * 1- >r
 r@ roll r@ roll r@ roll
 rdrop
 dup cs-item? ; 

: cs-push-part ( -- list addr )
 locals-list @ here ;

: cs-push-orig ( -- orig )
 cs-push-part dead-code @
 if
   dead-orig
 else
   live-orig
 then ;   

\ Structural Conditionals                              12dec92py

: ?struc      ( flag -- )       abort" unstructured " ;
: sys?        ( sys -- )        dup 0= ?struc ;
: >mark ( -- orig )
 cs-push-orig 0 , ;
: >resolve    ( addr -- )        here over - swap ! ;
: <resolve    ( addr -- )        here - , ;

: BUT
    1 cs-roll ;                      immediate restrict
: YET
    0 cs-pick ;                       immediate restrict

\ Structural Conditionals                              12dec92py

: AHEAD ( compilation -- orig ; run-time -- ) \ tools-ext
    POSTPONE branch  >mark  POSTPONE unreachable ; immediate restrict

: IF ( compilation -- orig ; run-time f -- ) \ core
 POSTPONE ?branch >mark ; immediate restrict

: ?DUP-IF ( compilation -- orig ; run-time n -- n| ) \ gforth	question-dupe-if
\G This is the preferred alternative to the idiom "?DUP IF", since it can be
\G better handled by tools like stack checkers. Besides, it's faster.
    POSTPONE ?dup-?branch >mark ;       immediate restrict

: ?DUP-0=-IF ( compilation -- orig ; run-time n -- n| ) \ gforth	question-dupe-zero-equals-if
    POSTPONE ?dup-0=-?branch >mark ;       immediate restrict

Defer then-like ( orig -- addr )
: cs>addr ( orig/dest -- addr )  drop nip ;
' cs>addr IS then-like

: THEN ( compilation orig -- ; run-time -- ) \ core
    dup orig?  then-like  >resolve ; immediate restrict

' THEN alias ENDIF ( compilation orig -- ; run-time -- ) \ gforth
immediate restrict
\ Same as "THEN". This is what you use if your program will be seen by
\ people who have not been brought up with Forth (or who have been
\ brought up with fig-Forth).

: ELSE ( compilation orig1 -- orig2 ; run-time f -- ) \ core
    POSTPONE ahead
    1 cs-roll
    POSTPONE then ; immediate restrict

Defer begin-like ( -- )
' noop IS begin-like

: BEGIN ( compilation -- dest ; run-time -- ) \ core
    begin-like cs-push-part dest ; immediate restrict

Defer again-like ( dest -- addr )
' nip IS again-like

: AGAIN ( compilation dest -- ; run-time -- ) \ core-ext
    dest? again-like  POSTPONE branch  <resolve ; immediate restrict

Defer until-like
: until, ( list addr xt1 xt2 -- )  drop compile, <resolve drop ;
' until, IS until-like

: UNTIL ( compilation dest -- ; run-time f -- ) \ core
    dest? ['] ?branch ['] ?branch-lp+!# until-like ; immediate restrict

: WHILE ( compilation dest -- orig dest ; run-time f -- ) \ core
    POSTPONE if
    1 cs-roll ; immediate restrict

: REPEAT ( compilation orig dest -- ; run-time -- ) \ core
    POSTPONE again
    POSTPONE then ; immediate restrict

\ counted loops

\ leave poses a little problem here
\ we have to store more than just the address of the branch, so the
\ traditional linked list approach is no longer viable.
\ This is solved by storing the information about the leavings in a
\ special stack.

\ !! remove the fixed size limit. 'Tis not hard.
20 constant leave-stack-size
create leave-stack  60 cells allot
Avariable leave-sp  leave-stack 3 cells + leave-sp !

: clear-leave-stack ( -- )
    leave-stack leave-sp ! ;

\ : leave-empty? ( -- f )
\  leave-sp @ leave-stack = ;

: >leave ( orig -- )
    \ push on leave-stack
    leave-sp @
    dup [ leave-stack 60 cells + ] Aliteral
    >= abort" leave-stack full"
    tuck ! cell+
    tuck ! cell+
    tuck ! cell+
    leave-sp ! ;

: leave> ( -- orig )
    \ pop from leave-stack
    leave-sp @
    dup leave-stack <= IF
       drop 0 0 0  EXIT  THEN
    cell - dup @ swap
    cell - dup @ swap
    cell - dup @ swap
    leave-sp ! ;

: DONE ( compilation orig -- ; run-time -- ) \ gforth
    \ !! the original done had ( addr -- )
    drop >r drop
    begin
	leave>
	over r@ u>=
    while
	POSTPONE then
    repeat
    >leave rdrop ; immediate restrict

: LEAVE ( compilation -- ; run-time loop-sys -- ) \ core
    POSTPONE ahead
    >leave ; immediate restrict

: ?LEAVE ( compilation -- ; run-time f | f loop-sys -- ) \ gforth	question-leave
    POSTPONE 0= POSTPONE if
    >leave ; immediate restrict

: DO ( compilation -- do-sys ; run-time w1 w2 -- loop-sys ) \ core
    POSTPONE (do)
    POSTPONE begin drop do-dest
    ( 0 0 0 >leave ) ; immediate restrict

: ?do-like ( -- do-sys )
    ( 0 0 0 >leave )
    >mark >leave
    POSTPONE begin drop do-dest ;

: ?DO ( compilation -- do-sys ; run-time w1 w2 -- | loop-sys )	\ core-ext	question-do
    POSTPONE (?do) ?do-like ; immediate restrict

: +DO ( compilation -- do-sys ; run-time n1 n2 -- | loop-sys )	\ gforth	plus-do
    POSTPONE (+do) ?do-like ; immediate restrict

: U+DO ( compilation -- do-sys ; run-time u1 u2 -- | loop-sys )	\ gforth	u-plus-do
    POSTPONE (u+do) ?do-like ; immediate restrict

: -DO ( compilation -- do-sys ; run-time n1 n2 -- | loop-sys )	\ gforth	minus-do
    POSTPONE (-do) ?do-like ; immediate restrict

: U-DO ( compilation -- do-sys ; run-time u1 u2 -- | loop-sys )	\ gforth	u-minus-do
    POSTPONE (u-do) ?do-like ; immediate restrict

: FOR ( compilation -- do-sys ; run-time u -- loop-sys )	\ gforth
    POSTPONE (for)
    POSTPONE begin drop do-dest
    ( 0 0 0 >leave ) ; immediate restrict

\ LOOP etc. are just like UNTIL

: loop-like ( do-sys xt1 xt2 -- )
    >r >r 0 cs-pick swap cell - swap 1 cs-roll r> r> rot do-dest?
    until-like  POSTPONE done  POSTPONE unloop ;

: LOOP ( compilation do-sys -- ; run-time loop-sys1 -- | loop-sys2 )	\ core
 ['] (loop) ['] (loop)-lp+!# loop-like ; immediate restrict

: +LOOP ( compilation do-sys -- ; run-time loop-sys1 n -- | loop-sys2 )	\ core	plus-loop
 ['] (+loop) ['] (+loop)-lp+!# loop-like ; immediate restrict

\ !! should the compiler warn about +DO..-LOOP?
: -LOOP ( compilation do-sys -- ; run-time loop-sys1 u -- | loop-sys2 )	\ gforth	minus-loop
 ['] (-loop) ['] (-loop)-lp+!# loop-like ; immediate restrict

\ A symmetric version of "+LOOP". I.e., "-high -low ?DO -inc S+LOOP"
\ will iterate as often as "high low ?DO inc S+LOOP". For positive
\ increments it behaves like "+LOOP". Use S+LOOP instead of +LOOP for
\ negative increments.
: S+LOOP ( compilation do-sys -- ; run-time loop-sys1 n -- | loop-sys2 )	\ gforth	s-plus-loop
 ['] (s+loop) ['] (s+loop)-lp+!# loop-like ; immediate restrict

: NEXT ( compilation do-sys -- ; run-time loop-sys1 -- | loop-sys2 ) \ gforth
 ['] (next) ['] (next)-lp+!# loop-like ; immediate restrict

\ Structural Conditionals                              12dec92py

Defer exit-like ( -- )
' noop IS exit-like

: EXIT ( compilation -- ; run-time nest-sys -- ) \ core
    exit-like
    POSTPONE ;s
    POSTPONE unreachable ; immediate restrict

: ?EXIT ( -- ) ( compilation -- ; run-time nest-sys f -- | nest-sys ) \ gforth
     POSTPONE if POSTPONE exit POSTPONE then ; immediate restrict

\ Strings                                              22feb93py

: ," ( "string"<"> -- ) [char] " parse
  here over char+ allot  place align ;
: "lit ( -- addr )
  r> r> dup count + aligned >r swap >r ;
: (.")     "lit count type ;
: (S")     "lit count ;
: SLiteral ( Compilation c-addr1 u ; run-time -- c-addr2 u ) \ string
    postpone (S") here over char+ allot  place align ;
                                             immediate restrict
: ( ( compilation 'ccc<close-paren>' -- ; run-time -- ) \ core,file	paren
    BEGIN
	>in @ [char] ) parse nip >in @ rot - =
    WHILE
	loadfile @ IF
	    refill 0= abort" missing ')' in paren comment"
	THEN
    REPEAT ;                       immediate
: \ ( -- ) \ core-ext backslash
    blk @
    IF
	>in @ c/l / 1+ c/l * >in !
	EXIT
    THEN
    source >in ! drop ; immediate

: \G ( -- ) \ gforth backslash
    POSTPONE \ ; immediate

\ error handling                                       22feb93py
\ 'abort thrown out!                                   11may93jaw

: (abort")
    "lit >r
    IF
	r> "error ! -2 throw
    THEN
    rdrop ;
: abort" ( compilation 'ccc"' -- ; run-time f -- ) \ core,exception-ext	abort-quote
    postpone (abort") ," ;        immediate restrict

\ Header states                                        23feb93py

: cset ( bmask c-addr -- )
    tuck c@ or swap c! ; 
: creset ( bmask c-addr -- )
    tuck c@ swap invert and swap c! ; 
: ctoggle ( bmask c-addr -- )
    tuck c@ xor swap c! ; 

: lastflags ( -- c-addr )
    \ the address of the flags byte in the last header
    \ aborts if the last defined word was headerless
    last @ dup 0= abort" last word was headerless" cell+ ;

: immediate ( -- ) \ core
    immediate-mask lastflags cset ;
: restrict ( -- ) \ gforth
    restrict-mask lastflags cset ;
' restrict alias compile-only ( -- ) \ gforth

\ Header                                               23feb93py

\ input-stream, nextname and noname are quite ugly (passing
\ information through global variables), but they are useful for dealing
\ with existing/independent defining words

defer (header)
defer header ( -- ) \ gforth
' (header) IS header

: string, ( c-addr u -- ) \ gforth
    \G puts down string as cstring
    dup c, here swap chars dup allot move ;

: header, ( c-addr u -- ) \ gforth
    name-too-long?
    align here last !
    current @ 1 or A,	\ link field; before revealing, it contains the
			\ tagged reveal-into wordlist
    string, cfalign
    alias-mask lastflags cset ;

: input-stream-header ( "name" -- )
    name name-too-short? header, ;
: input-stream ( -- )  \ general
    \G switches back to getting the name from the input stream ;
    ['] input-stream-header IS (header) ;

' input-stream-header IS (header)

\ !! make that a 2variable
create nextname-buffer 32 chars allot

: nextname-header ( -- )
    nextname-buffer count header,
    input-stream ;

\ the next name is given in the string
: nextname ( c-addr u -- ) \ gforth
    name-too-long?
    nextname-buffer c! ( c-addr )
    nextname-buffer count move
    ['] nextname-header IS (header) ;

: noname-header ( -- )
    0 last ! cfalign
    input-stream ;

: noname ( -- ) \ gforth
\ the next defined word remains anonymous. The xt of that word is given by lastxt
    ['] noname-header IS (header) ;

: lastxt ( -- xt ) \ gforth
\ xt is the execution token of the last word defined. The main purpose of this word is to get the xt of words defined using noname
    lastcfa @ ;

: Alias    ( cfa "name" -- ) \ gforth
    Header reveal
    alias-mask lastflags creset
    dup A, lastcfa ! ;

: name>string ( nfa -- addr count ) \ gforth	name-to-string
 cell+ count $1F and ;

Create ???  0 , 3 c, char ? c, char ? c, char ? c,
: >name ( cfa -- nfa ) \ gforth	to-name
 $21 cell do
   dup i - count $9F and + cfaligned over alias-mask + = if
     i - cell - unloop exit
   then
 cell +loop
 drop ??? ( wouldn't 0 be better? ) ;

\ threading                                   17mar93py

: cfa,     ( code-address -- )  \ gforth	cfa-comma
    here
    dup lastcfa !
    0 A, 0 ,  code-address! ;
: compile, ( xt -- )	\ core-ext	compile-comma
    A, ;
: !does    ( addr -- ) \ gforth	store-does
    lastxt does-code! ;
: (does>)  ( R: addr -- )
    r> /does-handler + !does ;
: dodoes,  ( -- )
  here /does-handler allot does-handler! ;

: Create ( "name" -- ) \ core
    Header reveal dovar: cfa, ;

\ Create Variable User Constant                        17mar93py

: Variable ( "name" -- ) \ core
    Create 0 , ;
: AVariable ( "name" -- ) \ gforth
    Create 0 A, ;
: 2VARIABLE ( "name" -- ) \ double
    create 0 , 0 , ;
    
: User ( "name" -- ) \ gforth
    Variable ;
: AUser ( "name" -- ) \ gforth
    AVariable ;

: (Constant)  Header reveal docon: cfa, ;
: Constant ( w "name" -- ) \ core
    \G Defines constant @var{name}
    \G  
    \G @var{name} execution: @var{-- w}
    (Constant) , ;
: AConstant ( addr "name" -- ) \ gforth
    (Constant) A, ;

: 2Constant ( w1 w2 "name" -- ) \ double
    Create ( w1 w2 "name" -- )
        2,
    DOES> ( -- w1 w2 )
        2@ ;
    
\ IS Defer What's Defers TO                            24feb93py

: Defer ( "name" -- ) \ gforth
    \ !! shouldn't it be initialized with abort or something similar?
    Header Reveal dodefer: cfa,
    ['] noop A, ;
\     Create ( -- ) 
\ 	['] noop A,
\     DOES> ( ??? )
\ 	perform ;

: Defers ( "name" -- ) \ gforth
    ' >body @ compile, ; immediate

\ : ;                                                  24feb93py

defer :-hook ( sys1 -- sys2 )
defer ;-hook ( sys2 -- sys1 )

: : ( "name" -- colon-sys ) \ core	colon
    Header docol: cfa, defstart ] :-hook ;
: ; ( compilation colon-sys -- ; run-time nest-sys ) \ core	semicolon
    ;-hook ?struc postpone exit reveal postpone [ ; immediate restrict

: :noname ( -- xt colon-sys ) \ core-ext	colon-no-name
    0 last !
    cfalign here docol: cfa, 0 ] :-hook ;

\ Search list handling                                 23feb93py

AVariable current ( -- addr ) \ gforth

: last?   ( -- false / nfa nfa )
    last @ ?dup ;
: (reveal) ( nfa wid -- )
    ( wid>wordlist-id ) dup >r
    @ over ( name>link ) ! 
    r> ! ;

\ object oriented search list                          17mar93py

\ word list structure:

struct
  1 cells: field find-method   \ xt: ( c_addr u wid -- name-id )
  1 cells: field reveal-method \ xt: ( nfa wid -- ) \ used by dofield:, must be field
  1 cells: field rehash-method \ xt: ( wid -- )
\   \ !! what else
end-struct wordlist-map-struct

struct
  1 cells: field wordlist-id \ not the same as wid; representation depends on implementation
  1 cells: field wordlist-map \ pointer to a wordlist-map-struct
  1 cells: field wordlist-link \ link field to other wordlists
  1 cells: field wordlist-extend \ points to wordlist extensions (eg hash)
end-struct wordlist-struct

: f83find      ( addr len wordlist -- nfa / false )
    ( wid>wordlist-id ) @ (f83find) ;

\ Search list table: find reveal
Create f83search ( -- wordlist-map )
    ' f83find A,  ' (reveal) A,  ' drop A,

Create forth-wordlist  NIL A, G f83search T A, NIL A, NIL A,
AVariable lookup       G forth-wordlist lookup T !
G forth-wordlist current T !

\ higher level parts of find

( struct )
0 >body cell
  1 cells: field interpret/compile-int
  1 cells: field interpret/compile-comp
end-struct interpret/compile-struct

: interpret/compile? ( xt -- flag )
    >does-code ['] S" >does-code = ;

: (cfa>int) ( cfa -- xt )
    dup interpret/compile?
    if
	interpret/compile-int @
    then ;

: (x>int) ( cfa b -- xt )
    \ get interpretation semantics of name
    restrict-mask and
    if
	drop ['] compile-only-error
    else
	(cfa>int)
    then ;

: name>int ( nfa -- xt ) \ gforth
    (name>x) (x>int) ;

: name?int ( nfa -- xt ) \ gforth
    \G like name>int, but throws an error if compile-only
    (name>x) restrict-mask and
    if
	compile-only-error \ does not return
    then
    (cfa>int) ;

: name>comp ( nfa -- w xt ) \ gforth
    \G get compilation semantics of name
    (name>x) >r dup interpret/compile?
    if
	interpret/compile-comp @
    then
    r> immediate-mask and if
	['] execute
    else
	['] compile,
    then ;

: (search-wordlist)  ( addr count wid -- nfa / false )
    dup wordlist-map @ find-method perform ;

: flag-sign ( f -- 1|-1 )
    \ true becomes 1, false -1
    0= 2* 1+ ;

: (name>intn) ( nfa -- xt +-1 )
    (name>x) tuck (x>int) ( b xt )
    swap immediate-mask and flag-sign ;

: search-wordlist ( addr count wid -- 0 / xt +-1 ) \ search
    \ xt is the interpretation semantics
    (search-wordlist) dup if
	(name>intn)
    then ;

: find-name ( c-addr u -- nfa/0 )
    lookup @ (search-wordlist) ;

: sfind ( c-addr u -- 0 / xt +-1  ) \ gforth-obsolete
    find-name dup
    if ( nfa )
	state @
	if
	    name>comp ['] execute = flag-sign
	else
	    (name>intn)
	then
    then ;

: find ( c-addr -- xt +-1 / c-addr 0 ) \ core
    dup count sfind dup
    if
	rot drop
    then ;

: (') ( "name" -- nfa ) \ gforth
    name find-name dup 0=
    IF
	drop -&13 bounce
    THEN  ;

: [(')]  ( compilation "name" -- ; run-time -- nfa ) \ gforth	bracket-paren-tick
    (') postpone ALiteral ; immediate restrict

: '    ( "name" -- xt ) \ core	tick
    (') name?int ;
: [']  ( compilation "name" -- ; run-time -- xt ) \ core	bracket-tick
    ' postpone ALiteral ; immediate restrict

: COMP'    ( "name" -- w xt ) \ gforth	c-tick
    (') name>comp ;
: [COMP']  ( compilation "name" -- ; run-time -- w xt ) \ gforth	bracket-comp-tick
    COMP' swap POSTPONE Aliteral POSTPONE ALiteral ; immediate restrict

\ reveal words

Variable warnings ( -- addr ) \ gforth
G -1 warnings T !

: check-shadow  ( addr count wid -- )
\G prints a warning if the string is already present in the wordlist
 >r 2dup 2dup r> (search-wordlist) warnings @ and ?dup if
   ." redefined " name>string 2dup type
   compare 0<> if
     ."  with " type
   else
     2drop
   then
   space space EXIT
 then
 2drop 2drop ;

: reveal ( -- ) \ gforth
    last?
    if \ the last word has a header
	dup ( name>link ) @ 1 and
	if \ it is still hidden
	    dup ( name>link ) @ 1 xor		( nfa wid )
	    2dup >r name>string r> check-shadow ( nfa wid )
	    dup wordlist-map @ reveal-method perform
	then
    then ;

: rehash  ( wid -- )
    dup wordlist-map @ rehash-method perform ;

\ Input                                                13feb93py

07 constant #bell ( -- c ) \ gforth
08 constant #bs ( -- c ) \ gforth
09 constant #tab ( -- c ) \ gforth
7F constant #del ( -- c ) \ gforth
0D constant #cr   ( -- c ) \ gforth
\ the newline key code
0C constant #ff ( -- c ) \ gforth
0A constant #lf ( -- c ) \ gforth

: bell  #bell emit ;
: cr ( -- ) \ core
    \ emit a newline
    #lf ( sic! ) emit ;

\ : backspaces  0 ?DO  #bs emit  LOOP ;

: (ins) ( max span addr pos1 key -- max span addr pos2 )
    >r 2dup + r@ swap c! r> emit 1+ rot 1+ -rot ;
: (bs) ( max span addr pos1 -- max span addr pos2 flag )
    dup IF
	#bs emit bl emit #bs emit 1- rot 1- -rot
    THEN false ;
: (ret)  true space ;

Create ctrlkeys
  ] false false false false  false false false false
    (bs)  false (ret) false  false (ret) false false
    false false false false  false false false false
    false false false false  false false false false [

defer insert-char
' (ins) IS insert-char
defer everychar
' noop IS everychar

: decode ( max span addr pos1 key -- max span addr pos2 flag )
  everychar
  dup #del = IF  drop #bs  THEN  \ del is rubout
  dup bl <   IF  cells ctrlkeys + perform  EXIT  THEN
  >r 2over = IF  rdrop bell 0 EXIT  THEN
  r> insert-char 0 ;

: accept   ( addr len -- len ) \ core
  dup 0< IF    abs over dup 1 chars - c@ tuck type 
\ this allows to edit given strings
         ELSE  0  THEN rot over
  BEGIN  key decode  UNTIL
  2drop nip ;

\ Output                                               13feb93py

: (type) ( c-addr u -- ) \ gforth
    outfile-id write-file drop \ !! use ?DUP-IF THROW ENDIF instead of DROP ?
;

Defer type ( c-addr u -- ) \ core
\ defer type for a output buffer or fast
\ screen write

' (type) IS Type

: (emit) ( c -- ) \ gforth
    outfile-id emit-file drop \ !! use ?DUP-IF THROW ENDIF instead of DROP ?
;

Defer emit ( c -- ) \ core
' (Emit) IS Emit

Defer key ( -- c ) \ core
' (key) IS key

\ Query                                                07apr93py

: refill ( -- flag ) \ core-ext,block-ext,file-ext
  blk @  IF  1 blk +!  true  0 >in !  EXIT  THEN
  tib /line
  loadfile @ ?dup
  IF    read-line throw
  ELSE  sourceline# 0< IF 2drop false EXIT THEN
        accept true
  THEN
  1 loadline +!
  swap #tib ! 0 >in ! ;

: Query  ( -- ) \ core-ext
    \G obsolescent
    loadfile off  blk off  refill drop ;

\ File specifiers                                       11jun93jaw


\ 1 c, here char r c, 0 c,                0 c, 0 c, char b c, 0 c,
\ 2 c, here char r c, char + c, 0 c,
\ 2 c, here char w c, char + c, 0 c, align
4 Constant w/o ( -- fam ) \ file	w-o
2 Constant r/w ( -- fam ) \ file	r-w
0 Constant r/o ( -- fam ) \ file	r-o

\ BIN WRITE-LINE                                        11jun93jaw

\ : bin           dup 1 chars - c@
\                 r/o 4 chars + over - dup >r swap move r> ;

: bin ( fam1 -- fam2 ) \ file
    1 or ;

create nl$ 1 c, A c, 0 c, \ gnu includes usually a cr in dos
                           \ or not unix environments if
                           \ bin is not selected

: write-line ( c-addr u fileid -- ior ) \ file
    dup >r write-file
    ?dup IF
	r> drop EXIT
    THEN
    nl$ count r> write-file ;

\ include-file                                         07apr93py

: push-file  ( -- )  r>
  sourceline# >r  loadfile @ >r
  blk @ >r  tibstack @ >r  >tib @ >r  #tib @ >r
  >tib @ tibstack @ = IF  r@ tibstack +!  THEN
  tibstack @ >tib ! >in @ >r  >r ;

: pop-file   ( throw-code -- throw-code )
  dup IF
         source >in @ sourceline# sourcefilename
	 error-stack dup @ dup 1+
	 max-errors 1- min error-stack !
	 6 * cells + cell+
	 5 cells bounds swap DO
	                    I !
	 -1 cells +LOOP
  THEN
  r>
  r> >in !  r> #tib !  r> >tib !  r> tibstack !  r> blk !
  r> loadfile ! r> loadline !  >r ;

: read-loop ( i*x -- j*x )
  BEGIN  refill  WHILE  interpret  REPEAT ;

: include-file ( i*x fid -- j*x ) \ file
  push-file  loadfile !
  0 loadline ! blk off  ['] read-loop catch
  loadfile @ close-file swap 2dup or
  pop-file  drop throw throw ;

create pathfilenamebuf 256 chars allot \ !! make this grow on demand

\ : check-file-prefix  ( addr len -- addr' len' flag )
\   dup 0=                    IF  true EXIT  THEN 
\   over c@ '/ =              IF  true EXIT  THEN 
\   over 2 S" ./" compare 0=  IF  true EXIT  THEN 
\   over 3 S" ../" compare 0= IF  true EXIT  THEN
\   over 2 S" ~/" compare 0=
\   IF     1 /string
\          S" HOME" getenv tuck pathfilenamebuf swap move
\          2dup + >r pathfilenamebuf + swap move
\          pathfilenamebuf r> true
\   ELSE   false
\   THEN ;

: absolut-path? ( addr u -- flag ) \ gforth
    \G a path is absolute, if it starts with a / or a ~ (~ expansion),
    \G or if it is in the form ./* or ../*, extended regexp: ^[/~]|./|../
    \G Pathes simply containing a / are not absolute!
    over c@ '/ = >r
    over c@ '~ = >r
    2dup 2 min S" ./" compare 0= >r
         3 min S" ../" compare 0=
    r> r> r> or or or ;
\   [char] / scan nip 0<> ;    

: open-path-file ( c-addr1 u1 -- file-id c-addr2 u2 ) \ gforth
    \G opens a file for reading, searching in the path for it (unless
    \G the filename contains a slash); c-addr2 u2 is the full filename
    \G (valid until the next call); if the file is not found (or in
    \G case of other errors for each try), -38 (non-existant file) is
    \G thrown. Opening for other access modes makes little sense, as
    \G the path will usually contain dirs that are only readable for
    \G the user
    \ !! use file-status to determine access mode?
    2dup absolut-path?
    if \ the filename contains a slash
	2dup r/o open-file throw ( c-addr1 u1 file-id )
	-rot >r pathfilenamebuf r@ cmove ( file-id R: u1 )
	pathfilenamebuf r> EXIT
    then
    pathdirs 2@ 0
\    check-file-prefix 0= 
\    IF  pathdirs 2@ 0
    ?DO ( c-addr1 u1 dirnamep )
	dup >r 2@ dup >r pathfilenamebuf swap cmove ( addr u )
	2dup pathfilenamebuf r@ chars + swap cmove ( addr u )
	pathfilenamebuf over r> + dup >r r/o open-file 0=
	IF ( addr u file-id )
	    nip nip r> rdrop 0 LEAVE
	THEN
	rdrop drop r> cell+ cell+
    LOOP
\    ELSE   2dup open-file throw -rot  THEN 
    0<> -&38 and throw ( file-id u2 )
    pathfilenamebuf swap ;

create included-files 0 , 0 , ( pointer to and count of included files )
here ," the terminal" dup c@ swap 1 + swap , A, here 2 cells -
create image-included-files  1 , A, ( pointer to and count of included files )
\ included-files points to ALLOCATEd space, while image-included-files
\ points to ALLOTed objects, so it survives a save-system

: loadfilename ( -- a-addr )
    \G a-addr 2@ produces the current file name ( c-addr u )
    included-files 2@ drop loadfilename# @ 2* cells + ;

: sourcefilename ( -- c-addr u ) \ gforth
    \G the name of the source file which is currently the input
    \G source.  The result is valid only while the file is being
    \G loaded.  If the current input source is no (stream) file, the
    \G result is undefined.
    loadfilename 2@ ;

: sourceline# ( -- u ) \ gforth		sourceline-number
    \G the line number of the line that is currently being interpreted
    \G from a (stream) file. The first line has the number 1. If the
    \G current input source is no (stream) file, the result is
    \G undefined.
    loadline @ ;

: init-included-files ( -- )
    image-included-files 2@ 2* cells save-mem drop ( addr )
    image-included-files 2@ nip included-files 2! ;

: included? ( c-addr u -- f ) \ gforth
    \G true, iff filename c-addr u is in included-files
    included-files 2@ 0
    ?do ( c-addr u addr )
	dup >r 2@ 2over compare 0=
	if
	    2drop rdrop unloop
	    true EXIT
	then
	r> cell+ cell+
    loop
    2drop drop false ;

: add-included-file ( c-addr u -- ) \ gforth
    \G add name c-addr u to included-files
    included-files 2@ 2* cells 2 cells extend-mem
    2/ cell / included-files 2!
    2! ;
\    included-files 2@ tuck 1+ 2* cells resize throw
\    swap 2dup 1+ included-files 2!
\    2* cells + 2! ;

: included1 ( i*x file-id c-addr u -- j*x ) \ gforth
    \G include the file file-id with the name given by c-addr u
    loadfilename# @ >r
    save-mem add-included-file ( file-id )
    included-files 2@ nip 1- loadfilename# !
    ['] include-file catch
    r> loadfilename# !
    throw ;
    
: included ( i*x addr u -- j*x ) \ file
    open-path-file included1 ;

: required ( i*x addr u -- j*x ) \ gforth
    \G include the file with the name given by addr u, if it is not
    \G included already. Currently this works by comparing the name of
    \G the file (with path) against the names of earlier included
    \G files; however, it would probably be better to fstat the file,
    \G and compare the device and inode. The advantages would be: no
    \G problems with several paths to the same file (e.g., due to
    \G links) and we would catch files included with include-file and
    \G write a require-file.
    open-path-file 2dup included?
    if
	2drop close-file throw
    else
	included1
    then ;

\ HEX DECIMAL                                           2may93jaw

: decimal ( -- ) \ core
    a base ! ;
: hex ( -- ) \ core-ext
    10 base ! ;

\ DEPTH                                                 9may93jaw

: depth ( -- +n ) \ core
    sp@ s0 @ swap - cell / ;
: clearstack ( ... -- )
    s0 @ sp! ;

\ INCLUDE                                               9may93jaw

: include  ( "file" -- ) \ gforth
  name included ;

: require  ( "file" -- ) \ gforth
  name required ;

\ RECURSE                                               17may93jaw

: recurse ( compilation -- ; run-time ?? -- ?? ) \ core
    lastxt compile, ; immediate restrict
' reveal alias recursive ( -- ) \ gforth
	immediate

\ */MOD */                                              17may93jaw

\ !! I think */mod should have the same rounding behaviour as / - anton
: */mod ( n1 n2 n3 -- n4 n5 ) \ core	star-slash-mod
    >r m* r> sm/rem ;

: */ ( n1 n2 n3 -- n4 ) \ core	star-slash
    */mod nip ;

\ EVALUATE                                              17may93jaw

: evaluate ( c-addr len -- ) \ core,block
  push-file  #tib ! >tib !
  >in off blk off loadfile off -1 loadline !
  ['] interpret catch
  pop-file throw ;

: abort ( ?? -- ?? ) \ core,exception-ext
    -1 throw ;

\+ environment? true ENV" CORE"
\ core wordset is now complete!

\ Quit                                                 13feb93py

Defer 'quit
Defer .status
: prompt        state @ IF ."  compiled" EXIT THEN ."  ok" ;
: (quit)        BEGIN .status cr query interpret prompt AGAIN ;
' (quit) IS 'quit

\ DOERROR (DOERROR)                                     13jun93jaw

8 Constant max-errors
Variable error-stack  0 error-stack !
max-errors 6 * cells allot
\ format of one cell:
\ source ( addr u )
\ >in
\ line-number
\ Loadfilename ( addr u )

: dec. ( n -- ) \ gforth
    \ print value in decimal representation
    base @ decimal swap . base ! ;

: hex. ( u -- ) \ gforth
    \ print value as unsigned hex number
    '$ emit base @ swap hex u. base ! ;

: typewhite ( addr u -- ) \ gforth
    \ like type, but white space is printed instead of the characters
    bounds ?do
	i c@ 9 = if \ check for tab
	    9
	else
	    bl
	then
	emit
    loop ;

DEFER DOERROR

: .error-frame ( addr1 u1 n1 n2 addr2 u2 -- )
  cr error-stack @
  IF
     ." in file included from "
     type ." :" dec.  drop 2drop
  ELSE
     type ." :" dec.
     cr dup 2over type cr drop
     nip -trailing 1- ( line-start index2 )
     0 >r  BEGIN
                  2dup + c@ bl >  WHILE
		  r> 1+ >r  1- dup 0<  UNTIL  THEN  1+
     ( line-start index1 )
     typewhite
     r> 1 max 0 ?do \ we want at least one "^", even if the length is 0
                  [char] ^ emit
     loop
  THEN
;

: (DoError) ( throw-code -- )
  sourceline# IF
               source >in @ sourceline# 0 0 .error-frame
  THEN
  error-stack @ 0 ?DO
    -1 error-stack +!
    error-stack dup @ 6 * cells + cell+
    6 cells bounds DO
      I @
    cell +LOOP
    .error-frame
  LOOP
  dup -2 =
  IF 
     "error @ ?dup
     IF
        cr count type 
     THEN
     drop
  ELSE
     .error
  THEN
  normal-dp dpp ! ;

' (DoError) IS DoError

: quit ( ?? -- ?? ) \ core
    r0 @ rp! handler off >tib @ >r
    BEGIN
	postpone [
	['] 'quit CATCH dup
    WHILE
	DoError r@ >tib ! r@ tibstack !
    REPEAT
    drop r> >tib ! ;

\ Cold                                                 13feb93py

\ : .name ( name -- ) name>string type space ;
\ : words  listwords @
\          BEGIN  @ dup  WHILE  dup .name  REPEAT drop ;

: cstring>sstring  ( cstring -- addr n ) \ gforth	cstring-to-sstring
    -1 0 scan 0 swap 1+ /string ;
: arg ( n -- addr count ) \ gforth
    cells argv @ + @ cstring>sstring ;
: #!       postpone \ ;  immediate

Create pathstring 2 cells allot \ string
Create pathdirs   2 cells allot \ dir string array, pointer and count
Variable argv
Variable argc

0 Value script? ( -- flag )

: process-path ( addr1 u1 -- addr2 u2 )
    \ addr1 u1 is a path string, addr2 u2 is an array of dir strings
    align here >r
    BEGIN
	over >r [char] : scan
	over r> tuck - ( rest-str this-str )
	dup
	IF
	    2dup 1- chars + c@ [char] / <>
	    IF
		2dup chars + [char] / swap c!
		1+
	    THEN
	    2,
	ELSE
	    2drop
	THEN
	dup
    WHILE
	1 /string
    REPEAT
    2drop
    here r> tuck - 2 cells / ;

: do-option ( addr1 len1 addr2 len2 -- n )
    2swap
    2dup s" -e"         compare  0= >r
    2dup s" --evaluate" compare  0= r> or
    IF  2drop dup >r ['] evaluate catch
	?dup IF  dup >r DoError r> negate (bye)  THEN
	r> >tib +!  2 EXIT  THEN
    ." Unknown option: " type cr 2drop 1 ;

: process-args ( -- )
    >tib @ >r
    argc @ 1
    ?DO
	I arg over c@ [char] - <>
	IF
	    required 1
	ELSE
	    I 1+ argc @ =  IF  s" "  ELSE  I 1+ arg  THEN
	    do-option
	THEN
    +LOOP
    r> >tib ! ;

Defer 'cold ' noop IS 'cold

: cold ( -- ) \ gforth
    stdout TO outfile-id
    pathstring 2@ process-path pathdirs 2!
    init-included-files
    'cold
    argc @ 1 >
    IF
	true to script?
	['] process-args catch ?dup
	IF
	    dup >r DoError cr r> negate (bye)
	THEN
	cr
    THEN
    false to script?
    ." GForth " version-string type ." , Copyright (C) 1994-1996 Free Software Foundation, Inc." cr
    ." GForth comes with ABSOLUTELY NO WARRANTY; for details type `license'" cr
    ." Type `bye' to exit"
    loadline off quit ;

: license ( -- ) \ gforth
 cr
 ." This program is free software; you can redistribute it and/or modify" cr
 ." it under the terms of the GNU General Public License as published by" cr
 ." the Free Software Foundation; either version 2 of the License, or" cr
 ." (at your option) any later version." cr cr

 ." This program is distributed in the hope that it will be useful," cr
 ." but WITHOUT ANY WARRANTY; without even the implied warranty of" cr
 ." MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the" cr
 ." GNU General Public License for more details." cr cr

 ." You should have received a copy of the GNU General Public License" cr
 ." along with this program; if not, write to the Free Software" cr
 ." Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA." cr ;

: boot ( path **argv argc -- )
  argc ! argv ! cstring>sstring pathstring 2!  main-task up!
  sp@ dup s0 ! $10 + dup >tib ! tibstack ! #tib off >in off
  rp@ r0 !  fp@ f0 !  ['] cold catch DoError bye ;

: bye ( -- ) \ tools-ext
    script? 0= IF  cr  THEN  0 (bye) ;

\ **argv may be scanned by the C starter to get some important
\ information, as -display and -geometry for an X client FORTH
\ or space and stackspace overrides

\ 0 arg contains, however, the name of the program.



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