File:  [gforth] / gforth / Attic / kernel.fs
Revision 1.10: download - view: text, annotated - select for diffs
Sat Jan 4 16:32:30 1997 UTC (24 years ago) by anton
Branches: MAIN
CVS tags: HEAD
reformatted errore.fs to single-column format
updated definition of UNUSED
fixed some documentation typos
removed FUZZ

    1: \ kernel.fs    GForth kernel                        17dec92py
    2: 
    3: \ Copyright (C) 1995 Free Software Foundation, Inc.
    4: 
    5: \ This file is part of Gforth.
    6: 
    7: \ Gforth is free software; you can redistribute it and/or
    8: \ modify it under the terms of the GNU General Public License
    9: \ as published by the Free Software Foundation; either version 2
   10: \ of the License, or (at your option) any later version.
   11: 
   12: \ This program is distributed in the hope that it will be useful,
   13: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
   14: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   15: \ GNU General Public License for more details.
   16: 
   17: \ You should have received a copy of the GNU General Public License
   18: \ along with this program; if not, write to the Free Software
   19: \ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   20: 
   21: \ Idea and implementation: Bernd Paysan (py)
   22: 
   23: HEX
   24: 
   25: \ labels for some code addresses
   26: 
   27: : docon: ( -- addr )	\ gforth
   28:     \G the code address of a @code{CONSTANT}
   29:     ['] bl >code-address ;
   30: 
   31: : docol: ( -- addr )	\ gforth
   32:     \G the code address of a colon definition
   33:     ['] docon: >code-address ;
   34: 
   35: : dovar: ( -- addr )	\ gforth
   36:     \G the code address of a @code{CREATE}d word
   37:     ['] udp >code-address ;
   38: 
   39: : douser: ( -- addr )	\ gforth
   40:     \G the code address of a @code{USER} variable
   41:     ['] s0 >code-address ;
   42: 
   43: : dodefer: ( -- addr )	\ gforth
   44:     \G the code address of a @code{defer}ed word
   45:     ['] source >code-address ;
   46: 
   47: : dofield: ( -- addr )	\ gforth
   48:     \G the code address of a @code{field}
   49:     ['] reveal-method >code-address ;
   50: 
   51: NIL AConstant NIL \ gforth
   52: 
   53: \ Bit string manipulation                              06oct92py
   54: 
   55: \ Create bits  80 c, 40 c, 20 c, 10 c, 8 c, 4 c, 2 c, 1 c,
   56: \ DOES> ( n -- )  + c@ ;
   57: 
   58: \ : >bit  ( addr n -- c-addr mask )  8 /mod rot + swap bits ;
   59: \ : +bit  ( addr n -- )  >bit over c@ or swap c! ;
   60: 
   61: \ : relinfo ( -- addr )  forthstart dup @ + !!bug!! ;
   62: \ : >rel  ( addr -- n )  forthstart - ;
   63: \ : relon ( addr -- )  relinfo swap >rel cell / +bit ;
   64: 
   65: \ here allot , c, A,                                   17dec92py
   66: 
   67: : dp	( -- addr ) \ gforth
   68:     dpp @ ;
   69: : here  ( -- here ) \ core
   70:     dp @ ;
   71: : allot ( n -- ) \ core
   72:     dp +! ;
   73: : c,    ( c -- ) \ core
   74:     here 1 chars allot c! ;
   75: : ,     ( x -- ) \ core
   76:     here cell allot  ! ;
   77: : 2,	( w1 w2 -- ) \ gforth
   78:     here 2 cells allot 2! ;
   79: 
   80: \ : aligned ( addr -- addr' ) \ core
   81: \     [ cell 1- ] Literal + [ -1 cells ] Literal and ;
   82: : align ( -- ) \ core
   83:     here dup aligned swap ?DO  bl c,  LOOP ;
   84: 
   85: \ : faligned ( addr -- f-addr ) \ float
   86: \     [ 1 floats 1- ] Literal + [ -1 floats ] Literal and ;
   87: 
   88: : falign ( -- ) \ float
   89:     here dup faligned swap
   90:     ?DO
   91: 	bl c,
   92:     LOOP ;
   93: 
   94: \ !! this is machine-dependent, but works on all but the strangest machines
   95: ' faligned Alias maxaligned ( addr1 -- addr2 ) \ gforth
   96: ' falign Alias maxalign ( -- ) \ gforth
   97: 
   98: \ !! machine-dependent and won't work if "0 >body" <> "0 >body maxaligned"
   99: ' maxaligned Alias cfaligned ( addr1 -- addr2 ) \ gforth
  100: \ the code field is aligned if its body is maxaligned
  101: ' maxalign Alias cfalign ( -- ) \ gforth
  102: 
  103: : chars ( n1 -- n2 ) \ core
  104: ; immediate
  105: 
  106: 
  107: \ : A!    ( addr1 addr2 -- ) \ gforth
  108: \    dup relon ! ;
  109: \ : A,    ( addr -- ) \ gforth
  110: \    here cell allot A! ;
  111: ' ! alias A! ( addr1 addr2 -- ) \ gforth
  112: ' , alias A, ( addr -- ) \ gforth 
  113: 
  114: 
  115: \ on off                                               23feb93py
  116: 
  117: : on  ( addr -- ) \ gforth
  118:     true  swap ! ;
  119: : off ( addr -- ) \ gforth
  120:     false swap ! ;
  121: 
  122: \ dabs roll                                           17may93jaw
  123: 
  124: : dabs ( d1 -- d2 ) \ double
  125:     dup 0< IF dnegate THEN ;
  126: 
  127: : roll  ( x0 x1 .. xn n -- x1 .. xn x0 ) \ core-ext
  128:   dup 1+ pick >r
  129:   cells sp@ cell+ dup cell+ rot move drop r> ;
  130: 
  131: \ name> found                                          17dec92py
  132: 
  133: $80 constant alias-mask \ set when the word is not an alias!
  134: $40 constant immediate-mask
  135: $20 constant restrict-mask
  136: 
  137: : ((name>))  ( nfa -- cfa )
  138:     name>string +  cfaligned ;
  139: 
  140: : (name>x) ( nfa -- cfa b )
  141:     \ cfa is an intermediate cfa and b is the flags byte of nfa
  142:     dup ((name>))
  143:     swap cell+ c@ dup alias-mask and 0=
  144:     IF
  145: 	swap @ swap
  146:     THEN ;
  147: 
  148: \ place bounds                                         13feb93py
  149: 
  150: : place  ( addr len to -- ) \ gforth
  151:     over >r  rot over 1+  r> move c! ;
  152: : bounds ( beg count -- end beg ) \ gforth
  153:     over + swap ;
  154: 
  155: : save-mem	( addr1 u -- addr2 u ) \ gforth
  156:     \g copy a memory block into a newly allocated region in the heap
  157:     swap >r
  158:     dup allocate throw
  159:     swap 2dup r> -rot move ;
  160: 
  161: : extend-mem	( addr1 u1 u -- addr addr2 u2 )
  162:     \ extend memory block allocated from the heap by u aus
  163:     \ the (possibly reallocated piece is addr2 u2, the extension is at addr
  164:     over >r + dup >r resize throw
  165:     r> over r> + -rot ;
  166: 
  167: \ input stream primitives                              23feb93py
  168: 
  169: : tib ( -- c-addr ) \ core-ext
  170:     \ obsolescent
  171:     >tib @ ;
  172: Defer source ( -- addr count ) \ core
  173: \ used by dodefer:, must be defer
  174: : (source) ( -- addr count )
  175:     tib #tib @ ;
  176: ' (source) IS source
  177: 
  178: \ (word)                                               22feb93py
  179: 
  180: : scan   ( addr1 n1 char -- addr2 n2 ) \ gforth
  181:     \ skip all characters not equal to char
  182:     >r
  183:     BEGIN
  184: 	dup
  185:     WHILE
  186: 	over c@ r@ <>
  187:     WHILE
  188: 	1 /string
  189:     REPEAT  THEN
  190:     rdrop ;
  191: : skip   ( addr1 n1 char -- addr2 n2 ) \ gforth
  192:     \ skip all characters equal to char
  193:     >r
  194:     BEGIN
  195: 	dup
  196:     WHILE
  197: 	over c@ r@  =
  198:     WHILE
  199: 	1 /string
  200:     REPEAT  THEN
  201:     rdrop ;
  202: 
  203: : (word) ( addr1 n1 char -- addr2 n2 )
  204:   dup >r skip 2dup r> scan  nip - ;
  205: 
  206: \ (word) should fold white spaces
  207: \ this is what (parse-white) does
  208: 
  209: \ word parse                                           23feb93py
  210: 
  211: : parse-word  ( char -- addr len ) \ gforth
  212:   source 2dup >r >r >in @ over min /string
  213:   rot dup bl = IF  drop (parse-white)  ELSE  (word)  THEN
  214:   2dup + r> - 1+ r> min >in ! ;
  215: : word   ( char -- addr ) \ core
  216:   parse-word here place  bl here count + c!  here ;
  217: 
  218: : parse    ( char -- addr len ) \ core-ext
  219:   >r  source  >in @ over min /string  over  swap r>  scan >r
  220:   over - dup r> IF 1+ THEN  >in +! ;
  221: 
  222: \ name                                                 13feb93py
  223: 
  224: : capitalize ( addr len -- addr len ) \ gforth
  225:   2dup chars chars bounds
  226:   ?DO  I c@ toupper I c! 1 chars +LOOP ;
  227: : (name) ( -- c-addr count )
  228:     source 2dup >r >r >in @ /string (parse-white)
  229:     2dup + r> - 1+ r> min >in ! ;
  230: \    name count ;
  231: 
  232: : name-too-short? ( c-addr u -- c-addr u )
  233:     dup 0= -&16 and throw ;
  234: 
  235: : name-too-long? ( c-addr u -- c-addr u )
  236:     dup $1F u> -&19 and throw ;
  237: 
  238: \ Literal                                              17dec92py
  239: 
  240: : Literal  ( compilation n -- ; run-time -- n ) \ core
  241:     postpone lit  , ; immediate restrict
  242: : ALiteral ( compilation addr -- ; run-time -- addr ) \ gforth
  243:     postpone lit A, ; immediate restrict
  244: 
  245: : char   ( 'char' -- n ) \ core
  246:     bl word char+ c@ ;
  247: : [char] ( compilation 'char' -- ; run-time -- n )
  248:     char postpone Literal ; immediate restrict
  249: 
  250: : (compile) ( -- ) \ gforth
  251:     r> dup cell+ >r @ compile, ;
  252: 
  253: : postpone, ( w xt -- )
  254:     \g Compiles the compilation semantics represented by @var{w xt}.
  255:     dup ['] execute =
  256:     if
  257: 	drop compile,
  258:     else
  259: 	dup ['] compile, =
  260: 	if
  261: 	    drop POSTPONE (compile) compile,
  262: 	else
  263: 	    swap POSTPONE aliteral compile,
  264: 	then
  265:     then ;
  266: 
  267: : POSTPONE ( "name" -- ) \ core
  268:     \g Compiles the compilation semantics of @var{name}.
  269:     COMP' postpone, ; immediate restrict
  270: 
  271: : interpret/compile: ( interp-xt comp-xt "name" -- ) \ gforth
  272:     Create immediate swap A, A,
  273: DOES>
  274:     abort" executed primary cfa of an interpret/compile: word" ;
  275: \    state @ IF  cell+  THEN  perform ;
  276: 
  277: \ Use (compile) for the old behavior of compile!
  278: 
  279: \ digit?                                               17dec92py
  280: 
  281: : digit?   ( char -- digit true/ false ) \ gforth
  282:   base @ $100 =
  283:   IF
  284:     true EXIT
  285:   THEN
  286:   toupper [char] 0 - dup 9 u> IF
  287:     [ 'A '9 1 + -  ] literal -
  288:     dup 9 u<= IF
  289:       drop false EXIT
  290:     THEN
  291:   THEN
  292:   dup base @ u>= IF
  293:     drop false EXIT
  294:   THEN
  295:   true ;
  296: 
  297: : accumulate ( +d0 addr digit - +d1 addr )
  298:   swap >r swap  base @  um* drop rot  base @  um* d+ r> ;
  299: 
  300: : >number ( d addr count -- d addr count ) \ core
  301:     0
  302:     ?DO
  303: 	count digit?
  304:     WHILE
  305: 	accumulate
  306:     LOOP
  307:         0
  308:     ELSE
  309: 	1- I' I -
  310: 	UNLOOP
  311:     THEN ;
  312: 
  313: \ number? number                                       23feb93py
  314: 
  315: Create bases   10 ,   2 ,   A , 100 ,
  316: \              16     2    10   character
  317: \ !! this saving and restoring base is an abomination! - anton
  318: : getbase ( addr u -- addr' u' )
  319:     over c@ [char] $ - dup 4 u<
  320:     IF
  321: 	cells bases + @ base ! 1 /string
  322:     ELSE
  323: 	drop
  324:     THEN ;
  325: : s>number ( addr len -- d )
  326:     base @ >r  dpl on
  327:     over c@ '- =  dup >r
  328:     IF
  329: 	1 /string
  330:     THEN
  331:     getbase  dpl on  0 0 2swap
  332:     BEGIN
  333: 	dup >r >number dup
  334:     WHILE
  335: 	dup r> -
  336:     WHILE
  337: 	dup dpl ! over c@ [char] . =
  338:     WHILE
  339: 	1 /string
  340:     REPEAT  THEN
  341:         2drop rdrop dpl off
  342:     ELSE
  343: 	2drop rdrop r>
  344: 	IF
  345: 	    dnegate
  346: 	THEN
  347:     THEN
  348:     r> base ! ;
  349: 
  350: : snumber? ( c-addr u -- 0 / n -1 / d 0> )
  351:     s>number dpl @ 0=
  352:     IF
  353: 	2drop false  EXIT
  354:     THEN
  355:     dpl @ dup 0> 0= IF
  356: 	nip
  357:     THEN ;
  358: : number? ( string -- string 0 / n -1 / d 0> )
  359:     dup >r count snumber? dup if
  360: 	rdrop
  361:     else
  362: 	r> swap
  363:     then ;
  364: : s>d ( n -- d ) \ core		s-to-d
  365:     dup 0< ;
  366: : number ( string -- d )
  367:     number? ?dup 0= abort" ?"  0<
  368:     IF
  369: 	s>d
  370:     THEN ;
  371: 
  372: \ space spaces ud/mod                                  21mar93py
  373: decimal
  374: Create spaces ( u -- ) \ core
  375: bl 80 times \ times from target compiler! 11may93jaw
  376: DOES>   ( u -- )
  377:     swap
  378:     0 max 0 ?DO  I' I - &80 min 2dup type  +LOOP  drop ;
  379: Create backspaces
  380: 08 80 times \ times from target compiler! 11may93jaw
  381: DOES>   ( u -- )
  382:     swap
  383:     0 max 0 ?DO  I' I - &80 min 2dup type  +LOOP  drop ;
  384: hex
  385: : space ( -- ) \ core
  386:     1 spaces ;
  387: 
  388: : ud/mod ( ud1 u2 -- urem udquot ) \ gforth
  389:     >r 0 r@ um/mod r> swap >r
  390:     um/mod r> ;
  391: 
  392: : pad    ( -- addr ) \ core-ext
  393:   here [ $20 8 2* cells + 2 + cell+ ] Literal + aligned ;
  394: 
  395: \ hold <# #> sign # #s                                 25jan92py
  396: 
  397: : hold    ( char -- ) \ core
  398:     pad cell - -1 chars over +! @ c! ;
  399: 
  400: : <# ( -- ) \ core	less-number-sign
  401:     pad cell - dup ! ;
  402: 
  403: : #>      ( xd -- addr u ) \ core	number-sign-greater
  404:     2drop pad cell - dup @ tuck - ;
  405: 
  406: : sign    ( n -- ) \ core
  407:     0< IF  [char] - hold  THEN ;
  408: 
  409: : #       ( ud1 -- ud2 ) \ core		number-sign
  410:     base @ 2 max ud/mod rot 9 over <
  411:     IF
  412: 	[ char A char 9 - 1- ] Literal +
  413:     THEN
  414:     [char] 0 + hold ;
  415: 
  416: : #s      ( +d -- 0 0 ) \ core	number-sign-s
  417:     BEGIN
  418: 	# 2dup d0=
  419:     UNTIL ;
  420: 
  421: \ print numbers                                        07jun92py
  422: 
  423: : d.r ( d n -- ) \ double	d-dot-r
  424:     >r tuck  dabs  <# #s  rot sign #>
  425:     r> over - spaces  type ;
  426: 
  427: : ud.r ( ud n -- ) \ gforth	u-d-dot-r
  428:     >r <# #s #> r> over - spaces type ;
  429: 
  430: : .r ( n1 n2 -- ) \ core-ext	dot-r
  431:     >r s>d r> d.r ;
  432: : u.r ( u n -- )  \ core-ext	u-dot-r
  433:     0 swap ud.r ;
  434: 
  435: : d. ( d -- ) \ double	d-dot
  436:     0 d.r space ;
  437: : ud. ( ud -- ) \ gforth	u-d-dot
  438:     0 ud.r space ;
  439: 
  440: : . ( n -- ) \ core	dot
  441:     s>d d. ;
  442: : u. ( u -- ) \ core	u-dot
  443:     0 ud. ;
  444: 
  445: \ catch throw                                          23feb93py
  446: \ bounce                                                08jun93jaw
  447: 
  448: \ !! allow the user to add rollback actions    anton
  449: \ !! use a separate exception stack?           anton
  450: 
  451: : lp@ ( -- addr ) \ gforth	l-p-fetch
  452:  laddr# [ 0 , ] ;
  453: 
  454: : catch ( x1 .. xn xt -- y1 .. ym 0 / z1 .. zn error ) \ exception
  455:     sp@ >r
  456:     fp@ >r
  457:     lp@ >r
  458:     handler @ >r
  459:     rp@ handler !
  460:     execute
  461:     r> handler ! rdrop rdrop rdrop 0 ;
  462: 
  463: : throw ( y1 .. ym error/0 -- y1 .. ym / z1 .. zn error ) \ exception
  464:     ?DUP IF
  465: 	[ here 9 cells ! ] \ entry point for signal handler
  466: 	handler @ dup 0= IF
  467: 	    2 (bye)
  468: 	THEN
  469: 	rp!
  470: 	r> handler !
  471: 	r> lp!
  472: 	r> fp!
  473: 	r> swap >r sp! drop r>
  474:     THEN ;
  475: 
  476: \ Bouncing is very fine,
  477: \ programming without wasting time...   jaw
  478: : bounce ( y1 .. ym error/0 -- y1 .. ym error / y1 .. ym ) \ gforth
  479: \ a throw without data or fp stack restauration
  480:   ?DUP IF
  481:       handler @ rp!
  482:       r> handler !
  483:       r> lp!
  484:       rdrop
  485:       rdrop
  486:   THEN ;
  487: 
  488: \ ?stack                                               23feb93py
  489: 
  490: : ?stack ( ?? -- ?? ) \ gforth
  491:     sp@ s0 @ > IF    -4 throw  THEN
  492:     fp@ f0 @ > IF  -&45 throw  THEN  ;
  493: \ ?stack should be code -- it touches an empty stack!
  494: 
  495: \ interpret                                            10mar92py
  496: 
  497: Defer parser
  498: Defer name ( -- c-addr count ) \ gforth
  499: \ get the next word from the input buffer
  500: ' (name) IS name
  501: Defer compiler-notfound ( c-addr count -- )
  502: Defer interpreter-notfound ( c-addr count -- )
  503: 
  504: : no.extensions  ( addr u -- )
  505:     2drop -&13 bounce ;
  506: ' no.extensions IS compiler-notfound
  507: ' no.extensions IS interpreter-notfound
  508: 
  509: : compile-only-error ( ... -- )
  510:     -&14 throw ;
  511: 
  512: : interpret ( ?? -- ?? ) \ gforth
  513:     \ interpret/compile the (rest of the) input buffer
  514:     BEGIN
  515: 	?stack name dup
  516:     WHILE
  517: 	parser
  518:     REPEAT
  519:     2drop ;
  520: 
  521: \ interpreter compiler                                 30apr92py
  522: 
  523: \ not the most efficient implementations of interpreter and compiler
  524: : interpreter ( c-addr u -- ) 
  525:     2dup find-name dup
  526:     if
  527: 	nip nip name>int execute
  528:     else
  529: 	drop
  530: 	2dup 2>r snumber?
  531: 	IF
  532: 	    2rdrop
  533: 	ELSE
  534: 	    2r> interpreter-notfound
  535: 	THEN
  536:     then ;
  537: 
  538: : compiler ( c-addr u -- )
  539:     2dup find-name dup
  540:     if ( c-addr u nt )
  541: 	nip nip name>comp execute
  542:     else
  543: 	drop
  544: 	2dup snumber? dup
  545: 	IF
  546: 	    0>
  547: 	    IF
  548: 		swap postpone Literal
  549: 	    THEN
  550: 	    postpone Literal
  551: 	    2drop
  552: 	ELSE
  553: 	    drop compiler-notfound
  554: 	THEN
  555:     then ;
  556: 
  557: ' interpreter  IS  parser
  558: 
  559: : [ ( -- ) \ core	left-bracket
  560:     ['] interpreter  IS parser state off ; immediate
  561: : ] ( -- ) \ core	right-bracket
  562:     ['] compiler     IS parser state on  ;
  563: 
  564: here 0 , \ just a dummy, the real value of locals-list is patched into it in glocals.fs
  565: AConstant locals-list \ acts like a variable that contains
  566: 		      \ a linear list of locals names
  567: 
  568: 
  569: variable dead-code \ true if normal code at "here" would be dead
  570: variable backedge-locals
  571:     \ contains the locals list that BEGIN will assume to be live on
  572:     \ the back edge if the BEGIN is unreachable from above. Set by
  573:     \ ASSUME-LIVE, reset by UNREACHABLE.
  574: 
  575: : UNREACHABLE ( -- ) \ gforth
  576:     \ declares the current point of execution as unreachable
  577:     dead-code on
  578:     0 backedge-locals ! ; immediate
  579: 
  580: : ASSUME-LIVE ( orig -- orig ) \ gforth
  581:     \ used immediatly before a BEGIN that is not reachable from
  582:     \ above.  causes the BEGIN to assume that the same locals are live
  583:     \ as at the orig point
  584:     dup orig?
  585:     2 pick backedge-locals ! ; immediate
  586:     
  587: \ Control Flow Stack
  588: \ orig, etc. have the following structure:
  589: \ type ( defstart, live-orig, dead-orig, dest, do-dest, scopestart) ( TOS )
  590: \ address (of the branch or the instruction to be branched to) (second)
  591: \ locals-list (valid at address) (third)
  592: 
  593: \ types
  594: 0 constant defstart
  595: 1 constant live-orig
  596: 2 constant dead-orig
  597: 3 constant dest \ the loopback branch is always assumed live
  598: 4 constant do-dest
  599: 5 constant scopestart
  600: 
  601: : def? ( n -- )
  602:     defstart <> abort" unstructured " ;
  603: 
  604: : orig? ( n -- )
  605:  dup live-orig <> swap dead-orig <> and abort" expected orig " ;
  606: 
  607: : dest? ( n -- )
  608:  dest <> abort" expected dest " ;
  609: 
  610: : do-dest? ( n -- )
  611:  do-dest <> abort" expected do-dest " ;
  612: 
  613: : scope? ( n -- )
  614:  scopestart <> abort" expected scope " ;
  615: 
  616: : non-orig? ( n -- )
  617:  dest scopestart 1+ within 0= abort" expected dest, do-dest or scope" ;
  618: 
  619: : cs-item? ( n -- )
  620:  live-orig scopestart 1+ within 0= abort" expected control flow stack item" ;
  621: 
  622: 3 constant cs-item-size
  623: 
  624: : CS-PICK ( ... u -- ... destu ) \ tools-ext
  625:  1+ cs-item-size * 1- >r
  626:  r@ pick  r@ pick  r@ pick
  627:  rdrop
  628:  dup non-orig? ;
  629: 
  630: : CS-ROLL ( destu/origu .. dest0/orig0 u -- .. dest0/orig0 destu/origu ) \ tools-ext
  631:  1+ cs-item-size * 1- >r
  632:  r@ roll r@ roll r@ roll
  633:  rdrop
  634:  dup cs-item? ; 
  635: 
  636: : cs-push-part ( -- list addr )
  637:  locals-list @ here ;
  638: 
  639: : cs-push-orig ( -- orig )
  640:  cs-push-part dead-code @
  641:  if
  642:    dead-orig
  643:  else
  644:    live-orig
  645:  then ;   
  646: 
  647: \ Structural Conditionals                              12dec92py
  648: 
  649: : ?struc      ( flag -- )       abort" unstructured " ;
  650: : sys?        ( sys -- )        dup 0= ?struc ;
  651: : >mark ( -- orig )
  652:  cs-push-orig 0 , ;
  653: : >resolve    ( addr -- )        here over - swap ! ;
  654: : <resolve    ( addr -- )        here - , ;
  655: 
  656: : BUT
  657:     1 cs-roll ;                      immediate restrict
  658: : YET
  659:     0 cs-pick ;                       immediate restrict
  660: 
  661: \ Structural Conditionals                              12dec92py
  662: 
  663: : AHEAD ( compilation -- orig ; run-time -- ) \ tools-ext
  664:     POSTPONE branch  >mark  POSTPONE unreachable ; immediate restrict
  665: 
  666: : IF ( compilation -- orig ; run-time f -- ) \ core
  667:  POSTPONE ?branch >mark ; immediate restrict
  668: 
  669: : ?DUP-IF ( compilation -- orig ; run-time n -- n| ) \ gforth	question-dupe-if
  670: \G This is the preferred alternative to the idiom "?DUP IF", since it can be
  671: \G better handled by tools like stack checkers. Besides, it's faster.
  672:     POSTPONE ?dup-?branch >mark ;       immediate restrict
  673: 
  674: : ?DUP-0=-IF ( compilation -- orig ; run-time n -- n| ) \ gforth	question-dupe-zero-equals-if
  675:     POSTPONE ?dup-0=-?branch >mark ;       immediate restrict
  676: 
  677: Defer then-like ( orig -- addr )
  678: : cs>addr ( orig/dest -- addr )  drop nip ;
  679: ' cs>addr IS then-like
  680: 
  681: : THEN ( compilation orig -- ; run-time -- ) \ core
  682:     dup orig?  then-like  >resolve ; immediate restrict
  683: 
  684: ' THEN alias ENDIF ( compilation orig -- ; run-time -- ) \ gforth
  685: immediate restrict
  686: \ Same as "THEN". This is what you use if your program will be seen by
  687: \ people who have not been brought up with Forth (or who have been
  688: \ brought up with fig-Forth).
  689: 
  690: : ELSE ( compilation orig1 -- orig2 ; run-time f -- ) \ core
  691:     POSTPONE ahead
  692:     1 cs-roll
  693:     POSTPONE then ; immediate restrict
  694: 
  695: Defer begin-like ( -- )
  696: ' noop IS begin-like
  697: 
  698: : BEGIN ( compilation -- dest ; run-time -- ) \ core
  699:     begin-like cs-push-part dest ; immediate restrict
  700: 
  701: Defer again-like ( dest -- addr )
  702: ' nip IS again-like
  703: 
  704: : AGAIN ( compilation dest -- ; run-time -- ) \ core-ext
  705:     dest? again-like  POSTPONE branch  <resolve ; immediate restrict
  706: 
  707: Defer until-like
  708: : until, ( list addr xt1 xt2 -- )  drop compile, <resolve drop ;
  709: ' until, IS until-like
  710: 
  711: : UNTIL ( compilation dest -- ; run-time f -- ) \ core
  712:     dest? ['] ?branch ['] ?branch-lp+!# until-like ; immediate restrict
  713: 
  714: : WHILE ( compilation dest -- orig dest ; run-time f -- ) \ core
  715:     POSTPONE if
  716:     1 cs-roll ; immediate restrict
  717: 
  718: : REPEAT ( compilation orig dest -- ; run-time -- ) \ core
  719:     POSTPONE again
  720:     POSTPONE then ; immediate restrict
  721: 
  722: \ counted loops
  723: 
  724: \ leave poses a little problem here
  725: \ we have to store more than just the address of the branch, so the
  726: \ traditional linked list approach is no longer viable.
  727: \ This is solved by storing the information about the leavings in a
  728: \ special stack.
  729: 
  730: \ !! remove the fixed size limit. 'Tis not hard.
  731: 20 constant leave-stack-size
  732: create leave-stack  60 cells allot
  733: Avariable leave-sp  leave-stack 3 cells + leave-sp !
  734: 
  735: : clear-leave-stack ( -- )
  736:     leave-stack leave-sp ! ;
  737: 
  738: \ : leave-empty? ( -- f )
  739: \  leave-sp @ leave-stack = ;
  740: 
  741: : >leave ( orig -- )
  742:     \ push on leave-stack
  743:     leave-sp @
  744:     dup [ leave-stack 60 cells + ] Aliteral
  745:     >= abort" leave-stack full"
  746:     tuck ! cell+
  747:     tuck ! cell+
  748:     tuck ! cell+
  749:     leave-sp ! ;
  750: 
  751: : leave> ( -- orig )
  752:     \ pop from leave-stack
  753:     leave-sp @
  754:     dup leave-stack <= IF
  755:        drop 0 0 0  EXIT  THEN
  756:     cell - dup @ swap
  757:     cell - dup @ swap
  758:     cell - dup @ swap
  759:     leave-sp ! ;
  760: 
  761: : DONE ( compilation orig -- ; run-time -- ) \ gforth
  762:     \ !! the original done had ( addr -- )
  763:     drop >r drop
  764:     begin
  765: 	leave>
  766: 	over r@ u>=
  767:     while
  768: 	POSTPONE then
  769:     repeat
  770:     >leave rdrop ; immediate restrict
  771: 
  772: : LEAVE ( compilation -- ; run-time loop-sys -- ) \ core
  773:     POSTPONE ahead
  774:     >leave ; immediate restrict
  775: 
  776: : ?LEAVE ( compilation -- ; run-time f | f loop-sys -- ) \ gforth	question-leave
  777:     POSTPONE 0= POSTPONE if
  778:     >leave ; immediate restrict
  779: 
  780: : DO ( compilation -- do-sys ; run-time w1 w2 -- loop-sys ) \ core
  781:     POSTPONE (do)
  782:     POSTPONE begin drop do-dest
  783:     ( 0 0 0 >leave ) ; immediate restrict
  784: 
  785: : ?do-like ( -- do-sys )
  786:     ( 0 0 0 >leave )
  787:     >mark >leave
  788:     POSTPONE begin drop do-dest ;
  789: 
  790: : ?DO ( compilation -- do-sys ; run-time w1 w2 -- | loop-sys )	\ core-ext	question-do
  791:     POSTPONE (?do) ?do-like ; immediate restrict
  792: 
  793: : +DO ( compilation -- do-sys ; run-time n1 n2 -- | loop-sys )	\ gforth	plus-do
  794:     POSTPONE (+do) ?do-like ; immediate restrict
  795: 
  796: : U+DO ( compilation -- do-sys ; run-time u1 u2 -- | loop-sys )	\ gforth	u-plus-do
  797:     POSTPONE (u+do) ?do-like ; immediate restrict
  798: 
  799: : -DO ( compilation -- do-sys ; run-time n1 n2 -- | loop-sys )	\ gforth	minus-do
  800:     POSTPONE (-do) ?do-like ; immediate restrict
  801: 
  802: : U-DO ( compilation -- do-sys ; run-time u1 u2 -- | loop-sys )	\ gforth	u-minus-do
  803:     POSTPONE (u-do) ?do-like ; immediate restrict
  804: 
  805: : FOR ( compilation -- do-sys ; run-time u -- loop-sys )	\ gforth
  806:     POSTPONE (for)
  807:     POSTPONE begin drop do-dest
  808:     ( 0 0 0 >leave ) ; immediate restrict
  809: 
  810: \ LOOP etc. are just like UNTIL
  811: 
  812: : loop-like ( do-sys xt1 xt2 -- )
  813:     >r >r 0 cs-pick swap cell - swap 1 cs-roll r> r> rot do-dest?
  814:     until-like  POSTPONE done  POSTPONE unloop ;
  815: 
  816: : LOOP ( compilation do-sys -- ; run-time loop-sys1 -- | loop-sys2 )	\ core
  817:  ['] (loop) ['] (loop)-lp+!# loop-like ; immediate restrict
  818: 
  819: : +LOOP ( compilation do-sys -- ; run-time loop-sys1 n -- | loop-sys2 )	\ core	plus-loop
  820:  ['] (+loop) ['] (+loop)-lp+!# loop-like ; immediate restrict
  821: 
  822: \ !! should the compiler warn about +DO..-LOOP?
  823: : -LOOP ( compilation do-sys -- ; run-time loop-sys1 u -- | loop-sys2 )	\ gforth	minus-loop
  824:  ['] (-loop) ['] (-loop)-lp+!# loop-like ; immediate restrict
  825: 
  826: \ A symmetric version of "+LOOP". I.e., "-high -low ?DO -inc S+LOOP"
  827: \ will iterate as often as "high low ?DO inc S+LOOP". For positive
  828: \ increments it behaves like "+LOOP". Use S+LOOP instead of +LOOP for
  829: \ negative increments.
  830: : S+LOOP ( compilation do-sys -- ; run-time loop-sys1 n -- | loop-sys2 )	\ gforth	s-plus-loop
  831:  ['] (s+loop) ['] (s+loop)-lp+!# loop-like ; immediate restrict
  832: 
  833: : NEXT ( compilation do-sys -- ; run-time loop-sys1 -- | loop-sys2 ) \ gforth
  834:  ['] (next) ['] (next)-lp+!# loop-like ; immediate restrict
  835: 
  836: \ Structural Conditionals                              12dec92py
  837: 
  838: Defer exit-like ( -- )
  839: ' noop IS exit-like
  840: 
  841: : EXIT ( compilation -- ; run-time nest-sys -- ) \ core
  842:     exit-like
  843:     POSTPONE ;s
  844:     POSTPONE unreachable ; immediate restrict
  845: 
  846: : ?EXIT ( -- ) ( compilation -- ; run-time nest-sys f -- | nest-sys ) \ gforth
  847:      POSTPONE if POSTPONE exit POSTPONE then ; immediate restrict
  848: 
  849: \ Strings                                              22feb93py
  850: 
  851: : ," ( "string"<"> -- ) [char] " parse
  852:   here over char+ allot  place align ;
  853: : "lit ( -- addr )
  854:   r> r> dup count + aligned >r swap >r ;
  855: : (.")     "lit count type ;
  856: : (S")     "lit count ;
  857: : SLiteral ( Compilation c-addr1 u ; run-time -- c-addr2 u ) \ string
  858:     postpone (S") here over char+ allot  place align ;
  859:                                              immediate restrict
  860: : ( ( compilation 'ccc<close-paren>' -- ; run-time -- ) \ core,file	paren
  861:     BEGIN
  862: 	>in @ [char] ) parse nip >in @ rot - =
  863:     WHILE
  864: 	loadfile @ IF
  865: 	    refill 0= abort" missing ')' in paren comment"
  866: 	THEN
  867:     REPEAT ;                       immediate
  868: : \ ( -- ) \ core-ext backslash
  869:     blk @
  870:     IF
  871: 	>in @ c/l / 1+ c/l * >in !
  872: 	EXIT
  873:     THEN
  874:     source >in ! drop ; immediate
  875: 
  876: : \G ( -- ) \ gforth backslash
  877:     POSTPONE \ ; immediate
  878: 
  879: \ error handling                                       22feb93py
  880: \ 'abort thrown out!                                   11may93jaw
  881: 
  882: : (abort")
  883:     "lit >r
  884:     IF
  885: 	r> "error ! -2 throw
  886:     THEN
  887:     rdrop ;
  888: : abort" ( compilation 'ccc"' -- ; run-time f -- ) \ core,exception-ext	abort-quote
  889:     postpone (abort") ," ;        immediate restrict
  890: 
  891: \ Header states                                        23feb93py
  892: 
  893: : cset ( bmask c-addr -- )
  894:     tuck c@ or swap c! ; 
  895: : creset ( bmask c-addr -- )
  896:     tuck c@ swap invert and swap c! ; 
  897: : ctoggle ( bmask c-addr -- )
  898:     tuck c@ xor swap c! ; 
  899: 
  900: : lastflags ( -- c-addr )
  901:     \ the address of the flags byte in the last header
  902:     \ aborts if the last defined word was headerless
  903:     last @ dup 0= abort" last word was headerless" cell+ ;
  904: 
  905: : immediate ( -- ) \ core
  906:     immediate-mask lastflags cset ;
  907: : restrict ( -- ) \ gforth
  908:     restrict-mask lastflags cset ;
  909: ' restrict alias compile-only ( -- ) \ gforth
  910: 
  911: \ Header                                               23feb93py
  912: 
  913: \ input-stream, nextname and noname are quite ugly (passing
  914: \ information through global variables), but they are useful for dealing
  915: \ with existing/independent defining words
  916: 
  917: defer (header)
  918: defer header ( -- ) \ gforth
  919: ' (header) IS header
  920: 
  921: : string, ( c-addr u -- ) \ gforth
  922:     \G puts down string as cstring
  923:     dup c, here swap chars dup allot move ;
  924: 
  925: : header, ( c-addr u -- ) \ gforth
  926:     name-too-long?
  927:     align here last !
  928:     current @ 1 or A,	\ link field; before revealing, it contains the
  929: 			\ tagged reveal-into wordlist
  930:     string, cfalign
  931:     alias-mask lastflags cset ;
  932: 
  933: : input-stream-header ( "name" -- )
  934:     name name-too-short? header, ;
  935: : input-stream ( -- )  \ general
  936:     \G switches back to getting the name from the input stream ;
  937:     ['] input-stream-header IS (header) ;
  938: 
  939: ' input-stream-header IS (header)
  940: 
  941: \ !! make that a 2variable
  942: create nextname-buffer 32 chars allot
  943: 
  944: : nextname-header ( -- )
  945:     nextname-buffer count header,
  946:     input-stream ;
  947: 
  948: \ the next name is given in the string
  949: : nextname ( c-addr u -- ) \ gforth
  950:     name-too-long?
  951:     nextname-buffer c! ( c-addr )
  952:     nextname-buffer count move
  953:     ['] nextname-header IS (header) ;
  954: 
  955: : noname-header ( -- )
  956:     0 last ! cfalign
  957:     input-stream ;
  958: 
  959: : noname ( -- ) \ gforth
  960: \ the next defined word remains anonymous. The xt of that word is given by lastxt
  961:     ['] noname-header IS (header) ;
  962: 
  963: : lastxt ( -- xt ) \ gforth
  964: \ 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
  965:     lastcfa @ ;
  966: 
  967: : Alias    ( cfa "name" -- ) \ gforth
  968:     Header reveal
  969:     alias-mask lastflags creset
  970:     dup A, lastcfa ! ;
  971: 
  972: : name>string ( nt -- addr count ) \ gforth	name-to-string
  973:     \g @var{addr count} is the name of the word represented by @var{nt}.
  974:     cell+ count $1F and ;
  975: 
  976: Create ???  0 , 3 c, char ? c, char ? c, char ? c,
  977: : >name ( cfa -- nt ) \ gforth	to-name
  978:  $21 cell do
  979:    dup i - count $9F and + cfaligned over alias-mask + = if
  980:      i - cell - unloop exit
  981:    then
  982:  cell +loop
  983:  drop ??? ( wouldn't 0 be better? ) ;
  984: 
  985: \ threading                                   17mar93py
  986: 
  987: : cfa,     ( code-address -- )  \ gforth	cfa-comma
  988:     here
  989:     dup lastcfa !
  990:     0 A, 0 ,  code-address! ;
  991: : compile, ( xt -- )	\ core-ext	compile-comma
  992:     A, ;
  993: : !does    ( addr -- ) \ gforth	store-does
  994:     lastxt does-code! ;
  995: : (does>)  ( R: addr -- )
  996:     r> /does-handler + !does ;
  997: : dodoes,  ( -- )
  998:   here /does-handler allot does-handler! ;
  999: 
 1000: : Create ( "name" -- ) \ core
 1001:     Header reveal dovar: cfa, ;
 1002: 
 1003: \ Create Variable User Constant                        17mar93py
 1004: 
 1005: : Variable ( "name" -- ) \ core
 1006:     Create 0 , ;
 1007: : AVariable ( "name" -- ) \ gforth
 1008:     Create 0 A, ;
 1009: : 2VARIABLE ( "name" -- ) \ double
 1010:     create 0 , 0 , ;
 1011:     
 1012: : User ( "name" -- ) \ gforth
 1013:     Variable ;
 1014: : AUser ( "name" -- ) \ gforth
 1015:     AVariable ;
 1016: 
 1017: : (Constant)  Header reveal docon: cfa, ;
 1018: : Constant ( w "name" -- ) \ core
 1019:     \G Defines constant @var{name}
 1020:     \G  
 1021:     \G @var{name} execution: @var{-- w}
 1022:     (Constant) , ;
 1023: : AConstant ( addr "name" -- ) \ gforth
 1024:     (Constant) A, ;
 1025: 
 1026: : 2Constant ( w1 w2 "name" -- ) \ double
 1027:     Create ( w1 w2 "name" -- )
 1028:         2,
 1029:     DOES> ( -- w1 w2 )
 1030:         2@ ;
 1031:     
 1032: \ IS Defer What's Defers TO                            24feb93py
 1033: 
 1034: : Defer ( "name" -- ) \ gforth
 1035:     \ !! shouldn't it be initialized with abort or something similar?
 1036:     Header Reveal dodefer: cfa,
 1037:     ['] noop A, ;
 1038: \     Create ( -- ) 
 1039: \ 	['] noop A,
 1040: \     DOES> ( ??? )
 1041: \ 	perform ;
 1042: 
 1043: : Defers ( "name" -- ) \ gforth
 1044:     ' >body @ compile, ; immediate
 1045: 
 1046: \ : ;                                                  24feb93py
 1047: 
 1048: defer :-hook ( sys1 -- sys2 )
 1049: defer ;-hook ( sys2 -- sys1 )
 1050: 
 1051: : : ( "name" -- colon-sys ) \ core	colon
 1052:     Header docol: cfa, defstart ] :-hook ;
 1053: : ; ( compilation colon-sys -- ; run-time nest-sys ) \ core	semicolon
 1054:     ;-hook ?struc postpone exit reveal postpone [ ; immediate restrict
 1055: 
 1056: : :noname ( -- xt colon-sys ) \ core-ext	colon-no-name
 1057:     0 last !
 1058:     cfalign here docol: cfa, 0 ] :-hook ;
 1059: 
 1060: \ Search list handling                                 23feb93py
 1061: 
 1062: AVariable current ( -- addr ) \ gforth
 1063: 
 1064: : last?   ( -- false / nfa nfa )
 1065:     last @ ?dup ;
 1066: : (reveal) ( nt wid -- )
 1067:     ( wid>wordlist-id ) dup >r
 1068:     @ over ( name>link ) ! 
 1069:     r> ! ;
 1070: 
 1071: \ object oriented search list                          17mar93py
 1072: 
 1073: \ word list structure:
 1074: 
 1075: struct
 1076:   1 cells: field find-method   \ xt: ( c_addr u wid -- nt )
 1077:   1 cells: field reveal-method \ xt: ( nt wid -- ) \ used by dofield:, must be field
 1078:   1 cells: field rehash-method \ xt: ( wid -- )
 1079: \   \ !! what else
 1080: end-struct wordlist-map-struct
 1081: 
 1082: struct
 1083:   1 cells: field wordlist-id \ not the same as wid; representation depends on implementation
 1084:   1 cells: field wordlist-map \ pointer to a wordlist-map-struct
 1085:   1 cells: field wordlist-link \ link field to other wordlists
 1086:   1 cells: field wordlist-extend \ points to wordlist extensions (eg hash)
 1087: end-struct wordlist-struct
 1088: 
 1089: : f83find      ( addr len wordlist -- nt / false )
 1090:     ( wid>wordlist-id ) @ (f83find) ;
 1091: 
 1092: \ Search list table: find reveal
 1093: Create f83search ( -- wordlist-map )
 1094:     ' f83find A,  ' (reveal) A,  ' drop A,
 1095: 
 1096: Create forth-wordlist  NIL A, G f83search T A, NIL A, NIL A,
 1097: AVariable lookup       G forth-wordlist lookup T !
 1098: G forth-wordlist current T !
 1099: 
 1100: \ higher level parts of find
 1101: 
 1102: ( struct )
 1103: 0 >body cell
 1104:   1 cells: field interpret/compile-int
 1105:   1 cells: field interpret/compile-comp
 1106: end-struct interpret/compile-struct
 1107: 
 1108: : interpret/compile? ( xt -- flag )
 1109:     >does-code ['] S" >does-code = ;
 1110: 
 1111: : (cfa>int) ( cfa -- xt )
 1112:     dup interpret/compile?
 1113:     if
 1114: 	interpret/compile-int @
 1115:     then ;
 1116: 
 1117: : (x>int) ( cfa b -- xt )
 1118:     \ get interpretation semantics of name
 1119:     restrict-mask and
 1120:     if
 1121: 	drop ['] compile-only-error
 1122:     else
 1123: 	(cfa>int)
 1124:     then ;
 1125: 
 1126: : name>int ( nt -- xt ) \ gforth
 1127:     \G @var{xt} represents the interpretation semantics of the word
 1128:     \G @var{nt}. Produces @code{' compile-only-error} if
 1129:     \G @var{nt} is compile-only.
 1130:     (name>x) (x>int) ;
 1131: 
 1132: : name?int ( nt -- xt ) \ gforth
 1133:     \G Like name>int, but throws an error if compile-only.
 1134:     (name>x) restrict-mask and
 1135:     if
 1136: 	compile-only-error \ does not return
 1137:     then
 1138:     (cfa>int) ;
 1139: 
 1140: : name>comp ( nt -- w xt ) \ gforth
 1141:     \G @var{w xt} is the compilation token for the word @var{nt}.
 1142:     (name>x) >r dup interpret/compile?
 1143:     if
 1144: 	interpret/compile-comp @
 1145:     then
 1146:     r> immediate-mask and if
 1147: 	['] execute
 1148:     else
 1149: 	['] compile,
 1150:     then ;
 1151: 
 1152: : (search-wordlist)  ( addr count wid -- nt / false )
 1153:     dup wordlist-map @ find-method perform ;
 1154: 
 1155: : flag-sign ( f -- 1|-1 )
 1156:     \ true becomes 1, false -1
 1157:     0= 2* 1+ ;
 1158: 
 1159: : (name>intn) ( nfa -- xt +-1 )
 1160:     (name>x) tuck (x>int) ( b xt )
 1161:     swap immediate-mask and flag-sign ;
 1162: 
 1163: : search-wordlist ( addr count wid -- 0 / xt +-1 ) \ search
 1164:     \ xt is the interpretation semantics
 1165:     (search-wordlist) dup if
 1166: 	(name>intn)
 1167:     then ;
 1168: 
 1169: : find-name ( c-addr u -- nt/0 ) \ gforth
 1170:     \g Find the name @var{c-addr u} in the current search
 1171:     \g order. Return its nt, if found, otherwise 0.
 1172:     lookup @ (search-wordlist) ;
 1173: 
 1174: : sfind ( c-addr u -- 0 / xt +-1  ) \ gforth-obsolete
 1175:     find-name dup
 1176:     if ( nt )
 1177: 	state @
 1178: 	if
 1179: 	    name>comp ['] execute = flag-sign
 1180: 	else
 1181: 	    (name>intn)
 1182: 	then
 1183:     then ;
 1184: 
 1185: : find ( c-addr -- xt +-1 / c-addr 0 ) \ core
 1186:     dup count sfind dup
 1187:     if
 1188: 	rot drop
 1189:     then ;
 1190: 
 1191: : (') ( "name" -- nt ) \ gforth
 1192:     name find-name dup 0=
 1193:     IF
 1194: 	drop -&13 bounce
 1195:     THEN  ;
 1196: 
 1197: : [(')]  ( compilation "name" -- ; run-time -- nt ) \ gforth	bracket-paren-tick
 1198:     (') postpone ALiteral ; immediate restrict
 1199: 
 1200: : '    ( "name" -- xt ) \ core	tick
 1201:     \g @var{xt} represents @var{name}'s interpretation
 1202:     \g semantics. Performs @code{-14 throw} if the word has no
 1203:     \g interpretation semantics.
 1204:     (') name?int ;
 1205: : [']  ( compilation. "name" -- ; run-time. -- xt ) \ core	bracket-tick
 1206:     \g @var{xt} represents @var{name}'s interpretation
 1207:     \g semantics. Performs @code{-14 throw} if the word has no
 1208:     \g interpretation semantics.
 1209:     ' postpone ALiteral ; immediate restrict
 1210: 
 1211: : COMP'    ( "name" -- w xt ) \ gforth	c-tick
 1212:     \g @var{w xt} represents @var{name}'s compilation semantics.
 1213:     (') name>comp ;
 1214: : [COMP']  ( compilation "name" -- ; run-time -- w xt ) \ gforth	bracket-comp-tick
 1215:     \g @var{w xt} represents @var{name}'s compilation semantics.
 1216:     COMP' swap POSTPONE Aliteral POSTPONE ALiteral ; immediate restrict
 1217: 
 1218: \ reveal words
 1219: 
 1220: Variable warnings ( -- addr ) \ gforth
 1221: G -1 warnings T !
 1222: 
 1223: : check-shadow  ( addr count wid -- )
 1224: \G prints a warning if the string is already present in the wordlist
 1225:  >r 2dup 2dup r> (search-wordlist) warnings @ and ?dup if
 1226:    ." redefined " name>string 2dup type
 1227:    compare 0<> if
 1228:      ."  with " type
 1229:    else
 1230:      2drop
 1231:    then
 1232:    space space EXIT
 1233:  then
 1234:  2drop 2drop ;
 1235: 
 1236: : reveal ( -- ) \ gforth
 1237:     last?
 1238:     if \ the last word has a header
 1239: 	dup ( name>link ) @ 1 and
 1240: 	if \ it is still hidden
 1241: 	    dup ( name>link ) @ 1 xor		( nt wid )
 1242: 	    2dup >r name>string r> check-shadow ( nt wid )
 1243: 	    dup wordlist-map @ reveal-method perform
 1244: 	then
 1245:     then ;
 1246: 
 1247: : rehash  ( wid -- )
 1248:     dup wordlist-map @ rehash-method perform ;
 1249: 
 1250: \ Input                                                13feb93py
 1251: 
 1252: 07 constant #bell ( -- c ) \ gforth
 1253: 08 constant #bs ( -- c ) \ gforth
 1254: 09 constant #tab ( -- c ) \ gforth
 1255: 7F constant #del ( -- c ) \ gforth
 1256: 0D constant #cr   ( -- c ) \ gforth
 1257: \ the newline key code
 1258: 0C constant #ff ( -- c ) \ gforth
 1259: 0A constant #lf ( -- c ) \ gforth
 1260: 
 1261: : bell  #bell emit ;
 1262: : cr ( -- ) \ core
 1263:     \ emit a newline
 1264:     #lf ( sic! ) emit ;
 1265: 
 1266: \ : backspaces  0 ?DO  #bs emit  LOOP ;
 1267: 
 1268: : (ins) ( max span addr pos1 key -- max span addr pos2 )
 1269:     >r 2dup + r@ swap c! r> emit 1+ rot 1+ -rot ;
 1270: : (bs) ( max span addr pos1 -- max span addr pos2 flag )
 1271:     dup IF
 1272: 	#bs emit bl emit #bs emit 1- rot 1- -rot
 1273:     THEN false ;
 1274: : (ret)  true space ;
 1275: 
 1276: Create ctrlkeys
 1277:   ] false false false false  false false false false
 1278:     (bs)  false (ret) false  false (ret) false false
 1279:     false false false false  false false false false
 1280:     false false false false  false false false false [
 1281: 
 1282: defer insert-char
 1283: ' (ins) IS insert-char
 1284: defer everychar
 1285: ' noop IS everychar
 1286: 
 1287: : decode ( max span addr pos1 key -- max span addr pos2 flag )
 1288:   everychar
 1289:   dup #del = IF  drop #bs  THEN  \ del is rubout
 1290:   dup bl <   IF  cells ctrlkeys + perform  EXIT  THEN
 1291:   >r 2over = IF  rdrop bell 0 EXIT  THEN
 1292:   r> insert-char 0 ;
 1293: 
 1294: : accept   ( addr len -- len ) \ core
 1295:   dup 0< IF    abs over dup 1 chars - c@ tuck type 
 1296: \ this allows to edit given strings
 1297:          ELSE  0  THEN rot over
 1298:   BEGIN  key decode  UNTIL
 1299:   2drop nip ;
 1300: 
 1301: \ Output                                               13feb93py
 1302: 
 1303: : (type) ( c-addr u -- ) \ gforth
 1304:     outfile-id write-file drop \ !! use ?DUP-IF THROW ENDIF instead of DROP ?
 1305: ;
 1306: 
 1307: Defer type ( c-addr u -- ) \ core
 1308: \ defer type for a output buffer or fast
 1309: \ screen write
 1310: 
 1311: ' (type) IS Type
 1312: 
 1313: : (emit) ( c -- ) \ gforth
 1314:     outfile-id emit-file drop \ !! use ?DUP-IF THROW ENDIF instead of DROP ?
 1315: ;
 1316: 
 1317: Defer emit ( c -- ) \ core
 1318: ' (Emit) IS Emit
 1319: 
 1320: Defer key ( -- c ) \ core
 1321: ' (key) IS key
 1322: 
 1323: \ Query                                                07apr93py
 1324: 
 1325: : refill ( -- flag ) \ core-ext,block-ext,file-ext
 1326:   blk @  IF  1 blk +!  true  0 >in !  EXIT  THEN
 1327:   tib /line
 1328:   loadfile @ ?dup
 1329:   IF    read-line throw
 1330:   ELSE  sourceline# 0< IF 2drop false EXIT THEN
 1331:         accept true
 1332:   THEN
 1333:   1 loadline +!
 1334:   swap #tib ! 0 >in ! ;
 1335: 
 1336: : query   ( -- ) \ core-ext
 1337:     \G obsolescent
 1338:     tib /line accept #tib ! 0 >in ! ;
 1339: 
 1340: \ File specifiers                                       11jun93jaw
 1341: 
 1342: 
 1343: \ 1 c, here char r c, 0 c,                0 c, 0 c, char b c, 0 c,
 1344: \ 2 c, here char r c, char + c, 0 c,
 1345: \ 2 c, here char w c, char + c, 0 c, align
 1346: 4 Constant w/o ( -- fam ) \ file	w-o
 1347: 2 Constant r/w ( -- fam ) \ file	r-w
 1348: 0 Constant r/o ( -- fam ) \ file	r-o
 1349: 
 1350: \ BIN WRITE-LINE                                        11jun93jaw
 1351: 
 1352: \ : bin           dup 1 chars - c@
 1353: \                 r/o 4 chars + over - dup >r swap move r> ;
 1354: 
 1355: : bin ( fam1 -- fam2 ) \ file
 1356:     1 or ;
 1357: 
 1358: : write-line ( c-addr u fileid -- ior ) \ file
 1359:     dup >r write-file
 1360:     ?dup IF
 1361: 	r> drop EXIT
 1362:     THEN
 1363:     #lf r> emit-file ;
 1364: 
 1365: \ include-file                                         07apr93py
 1366: 
 1367: : push-file  ( -- )  r>
 1368:   sourceline# >r  loadfile @ >r
 1369:   blk @ >r  tibstack @ >r  >tib @ >r  #tib @ >r
 1370:   >tib @ tibstack @ = IF  r@ tibstack +!  THEN
 1371:   tibstack @ >tib ! >in @ >r  >r ;
 1372: 
 1373: : pop-file   ( throw-code -- throw-code )
 1374:   dup IF
 1375:          source >in @ sourceline# sourcefilename
 1376: 	 error-stack dup @ dup 1+
 1377: 	 max-errors 1- min error-stack !
 1378: 	 6 * cells + cell+
 1379: 	 5 cells bounds swap DO
 1380: 	                    I !
 1381: 	 -1 cells +LOOP
 1382:   THEN
 1383:   r>
 1384:   r> >in !  r> #tib !  r> >tib !  r> tibstack !  r> blk !
 1385:   r> loadfile ! r> loadline !  >r ;
 1386: 
 1387: : read-loop ( i*x -- j*x )
 1388:   BEGIN  refill  WHILE  interpret  REPEAT ;
 1389: 
 1390: : include-file ( i*x fid -- j*x ) \ file
 1391:   push-file  loadfile !
 1392:   0 loadline ! blk off  ['] read-loop catch
 1393:   loadfile @ close-file swap 2dup or
 1394:   pop-file  drop throw throw ;
 1395: 
 1396: create pathfilenamebuf 256 chars allot \ !! make this grow on demand
 1397: 
 1398: \ : check-file-prefix  ( addr len -- addr' len' flag )
 1399: \   dup 0=                    IF  true EXIT  THEN 
 1400: \   over c@ '/ =              IF  true EXIT  THEN 
 1401: \   over 2 S" ./" compare 0=  IF  true EXIT  THEN 
 1402: \   over 3 S" ../" compare 0= IF  true EXIT  THEN
 1403: \   over 2 S" ~/" compare 0=
 1404: \   IF     1 /string
 1405: \          S" HOME" getenv tuck pathfilenamebuf swap move
 1406: \          2dup + >r pathfilenamebuf + swap move
 1407: \          pathfilenamebuf r> true
 1408: \   ELSE   false
 1409: \   THEN ;
 1410: 
 1411: : absolut-path? ( addr u -- flag ) \ gforth
 1412:     \G a path is absolute, if it starts with a / or a ~ (~ expansion),
 1413:     \G or if it is in the form ./* or ../*, extended regexp: ^[/~]|./|../
 1414:     \G Pathes simply containing a / are not absolute!
 1415:     over c@ '/ = >r
 1416:     over c@ '~ = >r
 1417:     2dup 2 min S" ./" compare 0= >r
 1418:          3 min S" ../" compare 0=
 1419:     r> r> r> or or or ;
 1420: \   [char] / scan nip 0<> ;    
 1421: 
 1422: : open-path-file ( c-addr1 u1 -- file-id c-addr2 u2 ) \ gforth
 1423:     \G opens a file for reading, searching in the path for it (unless
 1424:     \G the filename contains a slash); c-addr2 u2 is the full filename
 1425:     \G (valid until the next call); if the file is not found (or in
 1426:     \G case of other errors for each try), -38 (non-existant file) is
 1427:     \G thrown. Opening for other access modes makes little sense, as
 1428:     \G the path will usually contain dirs that are only readable for
 1429:     \G the user
 1430:     \ !! use file-status to determine access mode?
 1431:     2dup absolut-path?
 1432:     if \ the filename contains a slash
 1433: 	2dup r/o open-file throw ( c-addr1 u1 file-id )
 1434: 	-rot >r pathfilenamebuf r@ cmove ( file-id R: u1 )
 1435: 	pathfilenamebuf r> EXIT
 1436:     then
 1437:     pathdirs 2@ 0
 1438: \    check-file-prefix 0= 
 1439: \    IF  pathdirs 2@ 0
 1440:     ?DO ( c-addr1 u1 dirnamep )
 1441: 	dup >r 2@ dup >r pathfilenamebuf swap cmove ( addr u )
 1442: 	2dup pathfilenamebuf r@ chars + swap cmove ( addr u )
 1443: 	pathfilenamebuf over r> + dup >r r/o open-file 0=
 1444: 	IF ( addr u file-id )
 1445: 	    nip nip r> rdrop 0 LEAVE
 1446: 	THEN
 1447: 	rdrop drop r> cell+ cell+
 1448:     LOOP
 1449: \    ELSE   2dup open-file throw -rot  THEN 
 1450:     0<> -&38 and throw ( file-id u2 )
 1451:     pathfilenamebuf swap ;
 1452: 
 1453: create included-files 0 , 0 , ( pointer to and count of included files )
 1454: here ," the terminal" dup c@ swap 1 + swap , A, here 2 cells -
 1455: create image-included-files  1 , A, ( pointer to and count of included files )
 1456: \ included-files points to ALLOCATEd space, while image-included-files
 1457: \ points to ALLOTed objects, so it survives a save-system
 1458: 
 1459: : loadfilename ( -- a-addr )
 1460:     \G a-addr 2@ produces the current file name ( c-addr u )
 1461:     included-files 2@ drop loadfilename# @ 2* cells + ;
 1462: 
 1463: : sourcefilename ( -- c-addr u ) \ gforth
 1464:     \G the name of the source file which is currently the input
 1465:     \G source.  The result is valid only while the file is being
 1466:     \G loaded.  If the current input source is no (stream) file, the
 1467:     \G result is undefined.
 1468:     loadfilename 2@ ;
 1469: 
 1470: : sourceline# ( -- u ) \ gforth		sourceline-number
 1471:     \G the line number of the line that is currently being interpreted
 1472:     \G from a (stream) file. The first line has the number 1. If the
 1473:     \G current input source is no (stream) file, the result is
 1474:     \G undefined.
 1475:     loadline @ ;
 1476: 
 1477: : init-included-files ( -- )
 1478:     image-included-files 2@ 2* cells save-mem drop ( addr )
 1479:     image-included-files 2@ nip included-files 2! ;
 1480: 
 1481: : included? ( c-addr u -- f ) \ gforth
 1482:     \G true, iff filename c-addr u is in included-files
 1483:     included-files 2@ 0
 1484:     ?do ( c-addr u addr )
 1485: 	dup >r 2@ 2over compare 0=
 1486: 	if
 1487: 	    2drop rdrop unloop
 1488: 	    true EXIT
 1489: 	then
 1490: 	r> cell+ cell+
 1491:     loop
 1492:     2drop drop false ;
 1493: 
 1494: : add-included-file ( c-addr u -- ) \ gforth
 1495:     \G add name c-addr u to included-files
 1496:     included-files 2@ 2* cells 2 cells extend-mem
 1497:     2/ cell / included-files 2!
 1498:     2! ;
 1499: \    included-files 2@ tuck 1+ 2* cells resize throw
 1500: \    swap 2dup 1+ included-files 2!
 1501: \    2* cells + 2! ;
 1502: 
 1503: : included1 ( i*x file-id c-addr u -- j*x ) \ gforth
 1504:     \G include the file file-id with the name given by c-addr u
 1505:     loadfilename# @ >r
 1506:     save-mem add-included-file ( file-id )
 1507:     included-files 2@ nip 1- loadfilename# !
 1508:     ['] include-file catch
 1509:     r> loadfilename# !
 1510:     throw ;
 1511:     
 1512: : included ( i*x addr u -- j*x ) \ file
 1513:     open-path-file included1 ;
 1514: 
 1515: : required ( i*x addr u -- j*x ) \ gforth
 1516:     \G include the file with the name given by addr u, if it is not
 1517:     \G included already. Currently this works by comparing the name of
 1518:     \G the file (with path) against the names of earlier included
 1519:     \G files; however, it would probably be better to fstat the file,
 1520:     \G and compare the device and inode. The advantages would be: no
 1521:     \G problems with several paths to the same file (e.g., due to
 1522:     \G links) and we would catch files included with include-file and
 1523:     \G write a require-file.
 1524:     open-path-file 2dup included?
 1525:     if
 1526: 	2drop close-file throw
 1527:     else
 1528: 	included1
 1529:     then ;
 1530: 
 1531: \ HEX DECIMAL                                           2may93jaw
 1532: 
 1533: : decimal ( -- ) \ core
 1534:     a base ! ;
 1535: : hex ( -- ) \ core-ext
 1536:     10 base ! ;
 1537: 
 1538: \ DEPTH                                                 9may93jaw
 1539: 
 1540: : depth ( -- +n ) \ core
 1541:     sp@ s0 @ swap - cell / ;
 1542: : clearstack ( ... -- )
 1543:     s0 @ sp! ;
 1544: 
 1545: \ INCLUDE                                               9may93jaw
 1546: 
 1547: : include  ( "file" -- ) \ gforth
 1548:   name included ;
 1549: 
 1550: : require  ( "file" -- ) \ gforth
 1551:   name required ;
 1552: 
 1553: \ RECURSE                                               17may93jaw
 1554: 
 1555: : recurse ( compilation -- ; run-time ?? -- ?? ) \ core
 1556:     lastxt compile, ; immediate restrict
 1557: ' reveal alias recursive ( -- ) \ gforth
 1558: 	immediate
 1559: 
 1560: \ */MOD */                                              17may93jaw
 1561: 
 1562: \ !! I think */mod should have the same rounding behaviour as / - anton
 1563: : */mod ( n1 n2 n3 -- n4 n5 ) \ core	star-slash-mod
 1564:     >r m* r> sm/rem ;
 1565: 
 1566: : */ ( n1 n2 n3 -- n4 ) \ core	star-slash
 1567:     */mod nip ;
 1568: 
 1569: \ EVALUATE                                              17may93jaw
 1570: 
 1571: : evaluate ( c-addr len -- ) \ core,block
 1572:   push-file  #tib ! >tib !
 1573:   >in off blk off loadfile off -1 loadline !
 1574:   ['] interpret catch
 1575:   pop-file throw ;
 1576: 
 1577: : abort ( ?? -- ?? ) \ core,exception-ext
 1578:     -1 throw ;
 1579: 
 1580: \+ environment? true ENV" CORE"
 1581: \ core wordset is now complete!
 1582: 
 1583: \ Quit                                                 13feb93py
 1584: 
 1585: Defer 'quit
 1586: Defer .status
 1587: : prompt        state @ IF ."  compiled" EXIT THEN ."  ok" ;
 1588: : (Query)  ( -- )
 1589:     loadfile off  blk off  refill drop ;
 1590: : (quit)        BEGIN .status cr (query) interpret prompt AGAIN ;
 1591: ' (quit) IS 'quit
 1592: 
 1593: \ DOERROR (DOERROR)                                     13jun93jaw
 1594: 
 1595: 8 Constant max-errors
 1596: Variable error-stack  0 error-stack !
 1597: max-errors 6 * cells allot
 1598: \ format of one cell:
 1599: \ source ( addr u )
 1600: \ >in
 1601: \ line-number
 1602: \ Loadfilename ( addr u )
 1603: 
 1604: : dec. ( n -- ) \ gforth
 1605:     \ print value in decimal representation
 1606:     base @ decimal swap . base ! ;
 1607: 
 1608: : hex. ( u -- ) \ gforth
 1609:     \ print value as unsigned hex number
 1610:     '$ emit base @ swap hex u. base ! ;
 1611: 
 1612: : typewhite ( addr u -- ) \ gforth
 1613:     \ like type, but white space is printed instead of the characters
 1614:     bounds ?do
 1615: 	i c@ #tab = if \ check for tab
 1616: 	    #tab
 1617: 	else
 1618: 	    bl
 1619: 	then
 1620: 	emit
 1621:     loop ;
 1622: 
 1623: DEFER DOERROR
 1624: 
 1625: : .error-frame ( addr1 u1 n1 n2 addr2 u2 -- )
 1626:   cr error-stack @
 1627:   IF
 1628:      ." in file included from "
 1629:      type ." :" dec.  drop 2drop
 1630:   ELSE
 1631:      type ." :" dec.
 1632:      cr dup 2over type cr drop
 1633:      nip -trailing 1- ( line-start index2 )
 1634:      0 >r  BEGIN
 1635:                   2dup + c@ bl >  WHILE
 1636: 		  r> 1+ >r  1- dup 0<  UNTIL  THEN  1+
 1637:      ( line-start index1 )
 1638:      typewhite
 1639:      r> 1 max 0 ?do \ we want at least one "^", even if the length is 0
 1640:                   [char] ^ emit
 1641:      loop
 1642:   THEN
 1643: ;
 1644: 
 1645: : (DoError) ( throw-code -- )
 1646:   sourceline# IF
 1647:                source >in @ sourceline# 0 0 .error-frame
 1648:   THEN
 1649:   error-stack @ 0 ?DO
 1650:     -1 error-stack +!
 1651:     error-stack dup @ 6 * cells + cell+
 1652:     6 cells bounds DO
 1653:       I @
 1654:     cell +LOOP
 1655:     .error-frame
 1656:   LOOP
 1657:   dup -2 =
 1658:   IF 
 1659:      "error @ ?dup
 1660:      IF
 1661:         cr count type 
 1662:      THEN
 1663:      drop
 1664:   ELSE
 1665:      .error
 1666:   THEN
 1667:   normal-dp dpp ! ;
 1668: 
 1669: ' (DoError) IS DoError
 1670: 
 1671: : quit ( ?? -- ?? ) \ core
 1672:     r0 @ rp! handler off >tib @ >r
 1673:     BEGIN
 1674: 	postpone [
 1675: 	['] 'quit CATCH dup
 1676:     WHILE
 1677: 	DoError r@ >tib ! r@ tibstack !
 1678:     REPEAT
 1679:     drop r> >tib ! ;
 1680: 
 1681: \ Cold                                                 13feb93py
 1682: 
 1683: \ : .name ( name -- ) name>string type space ;
 1684: \ : words  listwords @
 1685: \          BEGIN  @ dup  WHILE  dup .name  REPEAT drop ;
 1686: 
 1687: : cstring>sstring  ( cstring -- addr n ) \ gforth	cstring-to-sstring
 1688:     -1 0 scan 0 swap 1+ /string ;
 1689: : arg ( n -- addr count ) \ gforth
 1690:     cells argv @ + @ cstring>sstring ;
 1691: : #!       postpone \ ;  immediate
 1692: 
 1693: Create pathstring 2 cells allot \ string
 1694: Create pathdirs   2 cells allot \ dir string array, pointer and count
 1695: Variable argv
 1696: Variable argc
 1697: 
 1698: 0 Value script? ( -- flag )
 1699: 
 1700: : process-path ( addr1 u1 -- addr2 u2 )
 1701:     \ addr1 u1 is a path string, addr2 u2 is an array of dir strings
 1702:     align here >r
 1703:     BEGIN
 1704: 	over >r 0 scan
 1705: 	over r> tuck - ( rest-str this-str )
 1706: 	dup
 1707: 	IF
 1708: 	    2dup 1- chars + c@ [char] / <>
 1709: 	    IF
 1710: 		2dup chars + [char] / swap c!
 1711: 		1+
 1712: 	    THEN
 1713: 	    2,
 1714: 	ELSE
 1715: 	    2drop
 1716: 	THEN
 1717: 	dup
 1718:     WHILE
 1719: 	1 /string
 1720:     REPEAT
 1721:     2drop
 1722:     here r> tuck - 2 cells / ;
 1723: 
 1724: : do-option ( addr1 len1 addr2 len2 -- n )
 1725:     2swap
 1726:     2dup s" -e"         compare  0= >r
 1727:     2dup s" --evaluate" compare  0= r> or
 1728:     IF  2drop dup >r ['] evaluate catch
 1729: 	?dup IF  dup >r DoError r> negate (bye)  THEN
 1730: 	r> >tib +!  2 EXIT  THEN
 1731:     ." Unknown option: " type cr 2drop 1 ;
 1732: 
 1733: : process-args ( -- )
 1734:     >tib @ >r
 1735:     argc @ 1
 1736:     ?DO
 1737: 	I arg over c@ [char] - <>
 1738: 	IF
 1739: 	    required 1
 1740: 	ELSE
 1741: 	    I 1+ argc @ =  IF  s" "  ELSE  I 1+ arg  THEN
 1742: 	    do-option
 1743: 	THEN
 1744:     +LOOP
 1745:     r> >tib ! ;
 1746: 
 1747: Defer 'cold ' noop IS 'cold
 1748: 
 1749: : cold ( -- ) \ gforth
 1750:     stdout TO outfile-id
 1751:     pathstring 2@ process-path pathdirs 2!
 1752:     init-included-files
 1753:     'cold
 1754:     argc @ 1 >
 1755:     IF
 1756: 	true to script?
 1757: 	['] process-args catch ?dup
 1758: 	IF
 1759: 	    dup >r DoError cr r> negate (bye)
 1760: 	THEN
 1761: 	cr
 1762:     THEN
 1763:     false to script?
 1764:     ." GForth " version-string type ." , Copyright (C) 1994-1996 Free Software Foundation, Inc." cr
 1765:     ." GForth comes with ABSOLUTELY NO WARRANTY; for details type `license'" cr
 1766:     ." Type `bye' to exit"
 1767:     loadline off quit ;
 1768: 
 1769: : license ( -- ) \ gforth
 1770:  cr
 1771:  ." This program is free software; you can redistribute it and/or modify" cr
 1772:  ." it under the terms of the GNU General Public License as published by" cr
 1773:  ." the Free Software Foundation; either version 2 of the License, or" cr
 1774:  ." (at your option) any later version." cr cr
 1775: 
 1776:  ." This program is distributed in the hope that it will be useful," cr
 1777:  ." but WITHOUT ANY WARRANTY; without even the implied warranty of" cr
 1778:  ." MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the" cr
 1779:  ." GNU General Public License for more details." cr cr
 1780: 
 1781:  ." You should have received a copy of the GNU General Public License" cr
 1782:  ." along with this program; if not, write to the Free Software" cr
 1783:  ." Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA." cr ;
 1784: 
 1785: : boot ( path **argv argc -- )
 1786:   argc ! argv ! pathstring 2!  main-task up!
 1787:   sp@ s0 !
 1788:   lp@ forthstart 7 cells + @ - dup >tib ! tibstack ! #tib off >in off
 1789:   rp@ r0 !
 1790:   fp@ f0 !
 1791:   ['] cold catch DoError
 1792:   bye ;
 1793: 
 1794: : bye ( -- ) \ tools-ext
 1795:     script? 0= IF  cr  THEN  0 (bye) ;
 1796: 
 1797: \ **argv may be scanned by the C starter to get some important
 1798: \ information, as -display and -geometry for an X client FORTH
 1799: \ or space and stackspace overrides
 1800: 
 1801: \ 0 arg contains, however, the name of the program.
 1802: 
 1803: 

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