Diff for /gforth/glocals.fs between versions 1.12 and 1.33

version 1.12, 1995/04/29 14:51:19 version 1.33, 1997/05/21 20:39:30
Line 1 Line 1
   \ A powerful locals implementation
   
   \ 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.
   
   
   \ More documentation can be found in the manual and in
   \ http://www.complang.tuwien.ac.at/papers/ertl94l.ps.gz
   
 \ Local variables are quite important for writing readable programs, but  \ Local variables are quite important for writing readable programs, but
 \ IMO (anton) they are the worst part of the standard. There they are very  \ IMO (anton) they are the worst part of the standard. There they are very
 \ restricted and have an ugly interface.  \ restricted and have an ugly interface.
Line 61 Line 85
 \ Currently locals may only be  \ Currently locals may only be
 \ defined at the outer level and TO is not supported.  \ defined at the outer level and TO is not supported.
   
 include search-order.fs  require search.fs
 include float.fs  require float.fs
   
 : compile-@local ( n -- ) \ new compile-fetch-local  : compile-@local ( n -- ) \ gforth compile-fetch-local
  case   case
     0       of postpone @local0 endof      0       of postpone @local0 endof
     1 cells of postpone @local1 endof      1 cells of postpone @local1 endof
Line 73  include float.fs Line 97  include float.fs
    ( otherwise ) dup postpone @local# ,     ( otherwise ) dup postpone @local# ,
  endcase ;   endcase ;
   
 : compile-f@local ( n -- ) \ new compile-f-fetch-local  : compile-f@local ( n -- ) \ gforth compile-f-fetch-local
  case   case
     0        of postpone f@local0 endof      0        of postpone f@local0 endof
     1 floats of postpone f@local1 endof      1 floats of postpone f@local1 endof
    ( otherwise ) dup postpone f@local# ,     ( otherwise ) dup postpone f@local# ,
  endcase ;   endcase ;
   
   \ locals stuff needed for control structures
   
   : compile-lp+! ( n -- ) \ gforth        compile-l-p-plus-store
       dup negate locals-size +!
       0 over = if
       else -1 cells  over = if postpone lp-
       else  1 floats over = if postpone lp+
       else  2 floats over = if postpone lp+2
       else postpone lp+!# dup ,
       then then then then drop ;
   
   : adjust-locals-size ( n -- ) \ gforth
       \ sets locals-size to n and generates an appropriate lp+!
       locals-size @ swap - compile-lp+! ;
   
 \ the locals stack grows downwards (see primitives)  \ the locals stack grows downwards (see primitives)
 \ of the local variables of a group (in braces) the leftmost is on top,  \ of the local variables of a group (in braces) the leftmost is on top,
 \ i.e. by going onto the locals stack the order is reversed.  \ i.e. by going onto the locals stack the order is reversed.
Line 118  variable locals-dp \ so here's the speci Line 157  variable locals-dp \ so here's the speci
     swap !      swap !
     postpone >l ;      postpone >l ;
   
   \ locals list operations
   
   : common-list ( list1 list2 -- list3 ) \ gforth-internal
   \ list1 and list2 are lists, where the heads are at higher addresses than
   \ the tail. list3 is the largest sublist of both lists.
    begin
      2dup u<>
    while
      2dup u>
      if
        swap
      then
      @
    repeat
    drop ;
   
   : sub-list? ( list1 list2 -- f ) \ gforth-internal
   \ true iff list1 is a sublist of list2
    begin
      2dup u<
    while
      @
    repeat
    = ;
   
   : list-size ( list -- u ) \ gforth-internal
   \ size of the locals frame represented by list
    0 ( list n )
    begin
      over 0<>
    while
      over
      ((name>)) >body @ max
      swap @ swap ( get next )
    repeat
    faligned nip ;
   
   : set-locals-size-list ( list -- )
    dup locals-list !
    list-size locals-size ! ;
   
   : check-begin ( list -- )
   \ warn if list is not a sublist of locals-list
    locals-list @ sub-list? 0= if
      \ !! print current position
      ." compiler was overly optimistic about locals at a BEGIN" cr
      \ !! print assumption and reality
    then ;
   
 : compile-pushlocal-f ( a-addr -- ) ( run-time: f -- )  : compile-pushlocal-f ( a-addr -- ) ( run-time: f -- )
     locals-size @ alignlp-f float+ dup locals-size !      locals-size @ alignlp-f float+ dup locals-size !
     swap !      swap !
Line 153  variable locals-dp \ so here's the speci Line 241  variable locals-dp \ so here's the speci
 vocabulary locals-types \ this contains all the type specifyers, -- and }  vocabulary locals-types \ this contains all the type specifyers, -- and }
 locals-types definitions  locals-types definitions
   
 : W:  : W: ( "name" -- a-addr xt ) \ gforth w-colon
     create-local ( "name" -- a-addr xt )      create-local
         \ xt produces the appropriate locals pushing code when executed          \ xt produces the appropriate locals pushing code when executed
         ['] compile-pushlocal-w          ['] compile-pushlocal-w
     does> ( Compilation: -- ) ( Run-time: -- w )      does> ( Compilation: -- ) ( Run-time: -- w )
         \ compiles a local variable access          \ compiles a local variable access
         @ lp-offset compile-@local ;          @ lp-offset compile-@local ;
   
 : W^  : W^ ( "name" -- a-addr xt ) \ gforth w-caret
     create-local ( "name" -- a-addr xt )      create-local
         ['] compile-pushlocal-w          ['] compile-pushlocal-w
     does> ( Compilation: -- ) ( Run-time: -- w )      does> ( Compilation: -- ) ( Run-time: -- w )
         postpone laddr# @ lp-offset, ;          postpone laddr# @ lp-offset, ;
   
 : F:  : F: ( "name" -- a-addr xt ) \ gforth f-colon
     create-local ( "name" -- a-addr xt )      create-local
         ['] compile-pushlocal-f          ['] compile-pushlocal-f
     does> ( Compilation: -- ) ( Run-time: -- w )      does> ( Compilation: -- ) ( Run-time: -- w )
         @ lp-offset compile-f@local ;          @ lp-offset compile-f@local ;
   
 : F^  : F^ ( "name" -- a-addr xt ) \ gforth f-caret
     create-local ( "name" -- a-addr xt )      create-local
         ['] compile-pushlocal-f          ['] compile-pushlocal-f
     does> ( Compilation: -- ) ( Run-time: -- w )      does> ( Compilation: -- ) ( Run-time: -- w )
         postpone laddr# @ lp-offset, ;          postpone laddr# @ lp-offset, ;
   
 : D:  : D: ( "name" -- a-addr xt ) \ gforth d-colon
     create-local ( "name" -- a-addr xt )      create-local
         ['] compile-pushlocal-d          ['] compile-pushlocal-d
     does> ( Compilation: -- ) ( Run-time: -- w )      does> ( Compilation: -- ) ( Run-time: -- w )
         postpone laddr# @ lp-offset, postpone 2@ ;          postpone laddr# @ lp-offset, postpone 2@ ;
   
 : D^  : D^ ( "name" -- a-addr xt ) \ gforth d-caret
     create-local ( "name" -- a-addr xt )      create-local
         ['] compile-pushlocal-d          ['] compile-pushlocal-d
     does> ( Compilation: -- ) ( Run-time: -- w )      does> ( Compilation: -- ) ( Run-time: -- w )
         postpone laddr# @ lp-offset, ;          postpone laddr# @ lp-offset, ;
   
 : C:  : C: ( "name" -- a-addr xt ) \ gforth c-colon
     create-local ( "name" -- a-addr xt )      create-local
         ['] compile-pushlocal-c          ['] compile-pushlocal-c
     does> ( Compilation: -- ) ( Run-time: -- w )      does> ( Compilation: -- ) ( Run-time: -- w )
         postpone laddr# @ lp-offset, postpone c@ ;          postpone laddr# @ lp-offset, postpone c@ ;
   
 : C^  : C^ ( "name" -- a-addr xt ) \ gforth c-caret
     create-local ( "name" -- a-addr xt )      create-local
         ['] compile-pushlocal-c          ['] compile-pushlocal-c
     does> ( Compilation: -- ) ( Run-time: -- w )      does> ( Compilation: -- ) ( Run-time: -- w )
         postpone laddr# @ lp-offset, ;          postpone laddr# @ lp-offset, ;
Line 230  previous Line 318  previous
 : new-locals-reveal ( -- )  : new-locals-reveal ( -- )
   true abort" this should not happen: new-locals-reveal" ;    true abort" this should not happen: new-locals-reveal" ;
   
 create new-locals-map ' new-locals-find A, ' new-locals-reveal A,  create new-locals-map ( -- wordlist-map )
   ' new-locals-find A,
   ' new-locals-reveal A,
   ' drop A, \ rehash method
   
   slowvoc @
   slowvoc on
 vocabulary new-locals  vocabulary new-locals
   slowvoc !
 new-locals-map ' new-locals >body cell+ A! \ !! use special access words  new-locals-map ' new-locals >body cell+ A! \ !! use special access words
   
 variable old-dpp  variable old-dpp
   
 \ and now, finally, the user interface words  \ and now, finally, the user interface words
 : { ( -- addr wid 0 )  : { ( -- lastxt wid 0 ) \ gforth open-brace
     dp old-dpp !      dp old-dpp !
     locals-dp dpp !      locals-dp dpp !
       lastxt get-current
     also new-locals      also new-locals
     also get-current locals definitions  locals-types      also locals definitions locals-types
     0 TO locals-wordlist      0 TO locals-wordlist
     0 postpone [ ; immediate      0 postpone [ ; immediate
   
 locals-types definitions  locals-types definitions
   
 : } ( addr wid 0 a-addr1 xt1 ... -- )  : } ( lastxt wid 0 a-addr1 xt1 ... -- ) \ gforth close-brace
     \ ends locals definitions      \ ends locals definitions
     ] old-dpp @ dpp !      ] old-dpp @ dpp !
     begin      begin
Line 258  locals-types definitions Line 353  locals-types definitions
     repeat      repeat
     drop      drop
     locals-size @ alignlp-f locals-size ! \ the strictest alignment      locals-size @ alignlp-f locals-size ! \ the strictest alignment
     set-current  
     previous previous      previous previous
       set-current lastcfa !
     locals-list TO locals-wordlist ;      locals-list TO locals-wordlist ;
   
 : -- ( addr wid 0 ... -- )  : -- ( addr wid 0 ... -- ) \ gforth dash-dash
     }      }
     [char] } parse 2drop ;      [char] } parse 2drop ;
   
Line 356  forth definitions Line 451  forth definitions
   
 \ If this assumption is too optimistic, the compiler will warn the user.  \ If this assumption is too optimistic, the compiler will warn the user.
   
 \ Implementation: migrated to kernal.fs  \ Implementation:
   
 \ THEN (another control flow from before joins the current one):  
 \ The new locals-list is the intersection of the current locals-list and  
 \ the orig-local-list. The new locals-size is the (alignment-adjusted)  
 \ size of the new locals-list. The following code is generated:  
 \ lp+!# (current-locals-size - orig-locals-size)  
 \ <then>:  
 \ lp+!# (orig-locals-size - new-locals-size)  
   
 \ Of course "lp+!# 0" is not generated. Still this is admittedly a bit  
 \ inefficient, e.g. if there is a locals declaration between IF and  
 \ ELSE. However, if ELSE generates an appropriate "lp+!#" before the  
 \ branch, there will be none after the target <then>.  
   
 \ explicit scoping  \ explicit scoping
   
 : scope ( -- scope )  : scope ( compilation  -- scope ; run-time  -- ) \ gforth
  cs-push-part scopestart ; immediate   cs-push-part scopestart ; immediate
   
 : endscope ( scope -- )  : endscope ( compilation scope -- ; run-time  -- ) \ gforth
  scope?   scope?
  drop   drop
  locals-list @ common-list   locals-list @ common-list
Line 403  forth definitions Line 485  forth definitions
     lastcfa ! last !      lastcfa ! last !
     DEFERS ;-hook ;      DEFERS ;-hook ;
   
   \ THEN (another control flow from before joins the current one):
   \ The new locals-list is the intersection of the current locals-list and
   \ the orig-local-list. The new locals-size is the (alignment-adjusted)
   \ size of the new locals-list. The following code is generated:
   \ lp+!# (current-locals-size - orig-locals-size)
   \ <then>:
   \ lp+!# (orig-locals-size - new-locals-size)
   
   \ Of course "lp+!# 0" is not generated. Still this is admittedly a bit
   \ inefficient, e.g. if there is a locals declaration between IF and
   \ ELSE. However, if ELSE generates an appropriate "lp+!#" before the
   \ branch, there will be none after the target <then>.
   
   : (then-like) ( orig -- )
       dead-orig =
       if
           >resolve drop
       else
           dead-code @
           if
               >resolve set-locals-size-list dead-code off
           else \ both live
               over list-size adjust-locals-size
               >resolve
               locals-list @ common-list dup list-size adjust-locals-size
               locals-list !
           then
       then ;
   
   : (begin-like) ( -- )
       dead-code @ if
           \ set up an assumption of the locals visible here.  if the
           \ users want something to be visible, they have to declare
           \ that using ASSUME-LIVE
           backedge-locals @ set-locals-size-list
       then
       dead-code off ;
   
   \ AGAIN (the current control flow joins another, earlier one):
   \ If the dest-locals-list is not a subset of the current locals-list,
   \ issue a warning (see below). The following code is generated:
   \ lp+!# (current-local-size - dest-locals-size)
   \ branch <begin>
   
   : (again-like) ( dest -- addr )
       over list-size adjust-locals-size
       swap check-begin  POSTPONE unreachable ;
   
   \ UNTIL (the current control flow may join an earlier one or continue):
   \ Similar to AGAIN. The new locals-list and locals-size are the current
   \ ones. The following code is generated:
   \ ?branch-lp+!# <begin> (current-local-size - dest-locals-size)
   
   : (until-like) ( list addr xt1 xt2 -- )
       \ list and addr are a fragment of a cs-item
       \ xt1 is the conditional branch without lp adjustment, xt2 is with
       >r >r
       locals-size @ 2 pick list-size - dup if ( list dest-addr adjustment )
           r> drop r> compile,
           swap <resolve ( list adjustment ) ,
       else ( list dest-addr adjustment )
           drop
           r> compile, <resolve
           r> drop
       then ( list )
       check-begin ;
   
   : (exit-like) ( -- )
       0 adjust-locals-size ;
   
 ' locals-:-hook IS :-hook  ' locals-:-hook IS :-hook
 ' locals-;-hook IS ;-hook  ' locals-;-hook IS ;-hook
   
   ' (then-like)  IS then-like
   ' (begin-like) IS begin-like
   ' (again-like) IS again-like
   ' (until-like) IS until-like
   ' (exit-like)  IS exit-like
   
 \ The words in the locals dictionary space are not deleted until the end  \ The words in the locals dictionary space are not deleted until the end
 \ of the current word. This is a bit too conservative, but very simple.  \ of the current word. This is a bit too conservative, but very simple.
   
Line 416  forth definitions Line 574  forth definitions
 \ things above are not control flow joins. Everything should be taken  \ things above are not control flow joins. Everything should be taken
 \ over from the live flow. No lp+!# is generated.  \ over from the live flow. No lp+!# is generated.
   
 \ !! The lp gymnastics for UNTIL are also a real problem: locals cannot be  
 \ used in signal handlers (or anything else that may be called while  
 \ locals live beyond the lp) without changing the locals stack.  
   
 \ About warning against uses of dead locals. There are several options:  \ About warning against uses of dead locals. There are several options:
   
 \ 1) Do not complain (After all, this is Forth;-)  \ 1) Do not complain (After all, this is Forth;-)
Line 449  forth definitions Line 603  forth definitions
   
 \ And here's finally the ANS standard stuff  \ And here's finally the ANS standard stuff
   
 : (local) ( addr u -- )  : (local) ( addr u -- ) \ local paren-local-paren
     \ a little space-inefficient, but well deserved ;-)      \ a little space-inefficient, but well deserved ;-)
     \ In exchange, there are no restrictions whatsoever on using (local)      \ In exchange, there are no restrictions whatsoever on using (local)
     \ as long as you use it in a definition      \ as long as you use it in a definition
Line 464  forth definitions Line 618  forth definitions
     \ this gives a unique identifier for the way the xt was defined      \ this gives a unique identifier for the way the xt was defined
     \ words defined with different does>-codes have different definers      \ words defined with different does>-codes have different definers
     \ the definer can be used for comparison and in definer!      \ the definer can be used for comparison and in definer!
     dup >code-address [ ' bits >code-address ] Literal =      dup >does-code
     \ !! this definition will not work on some implementations for `bits'      ?dup-if
     if  \ if >code-address delivers the same value for all does>-def'd words          nip 1 or
         >does-code 1 or \ bit 0 marks special treatment for does codes  
     else      else
         >code-address          >code-address
     then ;      then ;
Line 475  forth definitions Line 628  forth definitions
 : definer! ( definer xt -- )  : definer! ( definer xt -- )
     \ gives the word represented by xt the behaviour associated with definer      \ gives the word represented by xt the behaviour associated with definer
     over 1 and if      over 1 and if
         does-code!          swap [ 1 invert ] literal and does-code!
     else      else
         code-address!          code-address!
     then ;      then ;
   
 \ !! untested  :noname
 : TO ( c|w|d|r "name" -- )      ' dup >definer [ ' locals-wordlist ] literal >definer =
 \ !! state smart      if
  0 0 0. 0.0e0 { c: clocal w: wlocal d: dlocal f: flocal }          >body !
  ' dup >definer      else
  state @           -&32 throw
  if      endif ;
    case  :noname
      [ ' locals-wordlist >definer ] literal \ value      0 0 0. 0.0e0 { c: clocal w: wlocal d: dlocal f: flocal }
      OF >body POSTPONE Aliteral POSTPONE ! ENDOF      comp' drop dup >definer
      [ ' clocal >definer ] literal      case
      OF POSTPONE laddr# >body @ lp-offset, POSTPONE c! ENDOF          [ ' locals-wordlist ] literal >definer \ value
      [ ' wlocal >definer ] literal          OF >body POSTPONE Aliteral POSTPONE ! ENDOF
      OF POSTPONE laddr# >body @ lp-offset, POSTPONE ! ENDOF          [ comp' clocal drop ] literal >definer
      [ ' dlocal >definer ] literal          OF POSTPONE laddr# >body @ lp-offset, POSTPONE c! ENDOF
      OF POSTPONE laddr# >body @ lp-offset, POSTPONE d! ENDOF          [ comp' wlocal drop ] literal >definer
      [ ' flocal >definer ] literal          OF POSTPONE laddr# >body @ lp-offset, POSTPONE ! ENDOF
      OF POSTPONE laddr# >body @ lp-offset, POSTPONE f! ENDOF          [ comp' dlocal drop ] literal >definer
      -&32 throw          OF POSTPONE laddr# >body @ lp-offset, POSTPONE 2! ENDOF
    endcase          [ comp' flocal drop ] literal >definer
  else          OF POSTPONE laddr# >body @ lp-offset, POSTPONE f! ENDOF
    [ ' locals-wordlist >definer ] literal =          -&32 throw
    if      endcase ;
      >body !  interpret/compile: TO ( c|w|d|r "name" -- ) \ core-ext,local
    else  
      -&32 throw  
    endif  
  endif ; immediate  
   
 : locals|  : locals|
       \ don't use 'locals|'! use '{'! A portable and free '{'
       \ implementation is compat/anslocals.fs
     BEGIN      BEGIN
         name 2dup s" |" compare 0<>          name 2dup s" |" compare 0<>
     WHILE      WHILE
         (local)          (local)
     REPEAT      REPEAT
     drop 0 (local) ;  immediate restrict      drop 0 (local) ; immediate restrict

Removed from v.1.12  
changed lines
  Added in v.1.33


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