--- gforth/Attic/toolsext.fs	1994/02/11 16:30:47	1.1
+++ gforth/Attic/toolsext.fs	1996/07/16 20:57:14	1.8
@@ -1,78 +1,95 @@
-\ TOOLSEXT.FS [IF] [ELSE] [THEN] and more              20may93jaw
+\ Interpretative Structuren                            16feb92py
 
-\ This here is fully ans compatible
-\ May be cross-compiled
+\ Copyright (C) 1995 Free Software Foundation, Inc.
 
-\ ( \ added 09jun93jaw
+\ This file is part of Gforth.
 
-\ very close to dpANS5
-
-decimal
-
-CREATE Opennest  7 chars allot
-CREATE Closenest 7 chars allot
-
-: SKIPNEST
-      1 BEGIN
-          BEGIN name count dup WHILE
-                2dup Opennest count compare 0=
-                IF   2drop 1+
-                ELSE    Closenest count compare 0= IF 1- THEN
-                THEN
-                ?dup 0= ?EXIT
-          REPEAT
-          2drop refill 0=
-        UNTIL drop ;
-
-\ : (     s" (" Opennest place
-\         s" )" Closenest place
-\         SKIPNEST ; immediate
-
-: comment? ( c-addr u -- c-addr u )
-        2dup s" (" compare 0=
-        IF    postpone (
-        ELSE  2dup s" \" compare 0= IF postpone \ THEN
-        THEN ;
-
-: [ELSE]
-      1 BEGIN
-          BEGIN name count dup WHILE
-                comment?
-                2dup s" [IF]" compare 0=
-                IF   2drop 1+
-                ELSE 2dup s" [ELSE]" compare 0=
-                     IF   2drop 1- dup IF 1+ THEN
-                     ELSE s" [THEN]" compare 0= IF 1- THEN
-                     THEN
-                THEN
-                ?dup 0= ?EXIT
-          REPEAT
-          2drop refill 0=
-        UNTIL drop ; immediate
-
-: [THEN] ( -- ) ;    immediate
-
-: [IF] ( flag -- )
-        0= IF postpone [ELSE] THEN ; immediate
-
-\ [IFUNDEF] [IFDEF]                                     9may93jaw
-
-: [IFUNDEF]
-        name find nip 0= postpone [IF] ; immediate
-: [IFDEF]
-        name find nip 0<> postpone [IF] ; immediate
-
-
-\ [IF]?                                                 9jun93jaw
-
-\ same as comment? but skips [IF] .... [THEN]
-
-: [if]?   ( c-addr u -- c-addr u )
-        2dup s" [IF]" compare 0= >r
-        2dup s" [ELSE]" compare 0= >r
-        2dup s" [IFUNDEF]" compare 0= >r
-        2dup s" [IFDEF]" compare 0= r> or r> or r> or
-        IF   s" [IF]" Opennest place
-             s" [THEN]" Closenest place
-             SKIPNEST THEN ;
+\ 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.
+
+
+Variable countif
+
+: dummy ;  immediate
+: >exec  >r ; restrict ( :-)
+: scanIF   f83find  dup 0=  IF  drop ['] dummy >name  THEN  ;
+
+Create [struct]-search    ' scanIF A,  ' (reveal) A,  ' drop A,
+Create [struct]-voc       NIL A,       [struct]-search A,
+                          NIL A,       NIL A,
+
+: ?if  countif @ 0<
+  IF  [ [struct]-voc 3 cells + ] ALiteral @ lookup !  THEN ;
+
+UNLOCK  Tlast @ NIL Tlast !  LOCK
+
+: [IF]      1 countif +! ?if ;       immediate
+: [THEN]   -1 countif +! ?if ;       immediate
+: [ELSE]   postpone [THEN] r> >exec postpone [IF] ;
+                                     immediate
+' [IF]   Alias [IFDEF]               immediate
+' [IF]   Alias [IFUNDEF]             immediate
+' [THEN] Alias [ENDIF]                immediate
+' [IF]   Alias [BEGIN]               immediate
+' [IF]   Alias [WHILE]               immediate
+' [THEN] Alias [UNTIL]               immediate
+' [THEN] Alias [AGAIN]               immediate
+' [IF]   Alias [DO]                  immediate
+' [IF]   Alias [?DO]                 immediate
+' [THEN] Alias [LOOP]                immediate
+' [THEN] Alias [+LOOP]               immediate
+: [REPEAT]  postpone [AGAIN] postpone [THEN] ;
+                                     immediate
+' ( Alias (                          immediate
+' \ Alias \                          immediate
+
+UNLOCK Tlast @ swap Tlast ! LOCK
+1 cells - [struct]-voc !
+
+\ Interpretative Structuren                            30apr92py
+
+: defined   bl word find nip 0<> ; immediate
+: [IF] 0= IF  countif off
+              lookup @ [ [struct]-voc 3 cells + ] ALiteral !
+	      [struct]-voc lookup !
+          THEN ;                                      immediate
+: [IFDEF]   postpone defined    postpone [IF] ;       immediate
+: [IFUNDEF] postpone defined 0= postpone [IF] ;       immediate
+: [ELSE] 0 postpone [IF] ;                            immediate
+: [THEN] ;                                            immediate
+: [ENDIF] ;                                           immediate
+
+\ Structs for interpreter                              28nov92py
+
+User (i)
+
+: [DO]  ( start end -- )  >in @ -rot
+  DO   I (i) ! dup >r >in ! interpret r> swap +LOOP  drop ;
+                                                      immediate
+: [?DO] 2dup = IF 2drop postpone [ELSE] ELSE postpone [DO] THEN ;
+                                                      immediate
+: [+LOOP] ( n -- ) rdrop rdrop ;                      immediate
+: [LOOP] ( -- ) 1 rdrop rdrop ;                       immediate
+: [FOR] ( n -- )  0 swap postpone [DO] ;              immediate
+: [NEXT] ( n -- ) -1 rdrop rdrop ;                    immediate
+: [I] ( -- index ) (I) @ postpone Literal ;           immediate
+: [BEGIN] >in @ >r BEGIN r@ >in ! interpret UNTIL rdrop ;
+                                                      immediate
+' [+LOOP]  Alias [UNTIL] immediate
+: [REPEAT]  ( -- )  false rdrop rdrop ;               immediate
+' [REPEAT] Alias [AGAIN] immediate
+: [WHILE]   ( flag -- )
+  0= IF   postpone [ELSE] true rdrop rdrop 1 countif +!  THEN ;
+                                                      immediate