Diff for /gforth/except.fs between versions 1.10 and 1.19

version 1.10, 2006/05/26 21:18:45 version 1.19, 2007/02/23 14:50:02
Line 1 Line 1
 \ catch, throw, etc.  \ catch, throw, etc.
   
 \ Copyright (C) 1999,2000,2003 Free Software Foundation, Inc.  \ Copyright (C) 1999,2000,2003,2006 Free Software Foundation, Inc.
   
 \ This file is part of Gforth.  \ This file is part of Gforth.
   
Line 20 Line 20
   
 \ !! use a separate exception stack?           anton  \ !! use a separate exception stack?           anton
   
 \ user-definable rollback actions  
   
 Defer 'catch  
 Defer 'throw  
   
 ' noop IS 'catch  
 ' noop IS 'throw  
   
 \ has? backtrace [IF]  \ has? backtrace [IF]
 Defer store-backtrace  Defer store-backtrace
 ' noop IS store-backtrace  ' noop IS store-backtrace
Line 76  Defer store-backtrace Line 68  Defer store-backtrace
   
 \ !! explain handler on-stack structure  \ !! explain handler on-stack structure
   
   Variable first-throw
   : nothrow ( -- ) \ gforth
       \G Use this (or the standard sequence @code{['] false catch drop})
       \G after a @code{catch} or @code{endtry} that does not rethrow;
       \G this ensures that the next @code{throw} will record a
       \G backtrace.
       first-throw on ;
   
 : (try) ( ahandler -- )  : (try) ( ahandler -- )
       first-throw on
     r>      r>
     swap >r \ recovery address      swap >r \ recovery address
     rp@ 'catch >r  
     sp@ >r      sp@ >r
     fp@ >r      fp@ >r
     lp@ >r      lp@ >r
Line 87  Defer store-backtrace Line 87  Defer store-backtrace
     rp@ handler !      rp@ handler !
     >r ;      >r ;
   
 : try ( compilation  -- orig ; run-time  -- ) \ gforth  : try ( compilation  -- orig ; run-time  -- R:sys1 ) \ gforth
     \ !! does not work correctly for gforth-native      \G Start an exception-catching region.
     POSTPONE ahead here >r >mark 1 cs-roll POSTPONE then      POSTPONE ahead here >r >mark 1 cs-roll POSTPONE then
     r> POSTPONE literal POSTPONE (try) ; immediate compile-only      r> POSTPONE literal POSTPONE (try) ; immediate compile-only
   
 : (recover) ( -- )  : (endtry) ( -- )
     \ normal end of try block: restore handler, forget rest      \ normal end of try block: restore handler, forget rest
     r>      r>
     r> handler !      r> handler !
     rdrop \ lp      rdrop \ lp
     rdrop \ fp      rdrop \ fp
     rdrop \ sp      rdrop \ sp
     r> rp!  
     rdrop \ recovery address      rdrop \ recovery address
     >r ;      >r ;
   
 : recover ( compilation  orig1 -- orig2 ; run-time  -- ) \ gforth  : handler-intro, ( -- )
     \ !! check using a special tag  
     POSTPONE (recover)  
     POSTPONE else  
     docol: here 0 , 0 , code-address! \ start a colon def       docol: here 0 , 0 , code-address! \ start a colon def 
     postpone rdrop                    \ drop the return address      postpone rdrop                    \ drop the return address
   ;
   
   : iferror ( compilation  orig1 -- orig2 ; run-time  -- ) \ gforth
       \G Starts the exception handling code (executed if there is an
       \G exception between @code{try} and @code{endtry}).  This part has
       \G to be finished with @code{then}.
       \ !! check using a special tag
       POSTPONE else handler-intro,
 ; immediate compile-only  ; immediate compile-only
   
 : endtry ( compilation  orig -- ; run-time  -- ) \ gforth  : restore ( compilation  orig1 -- ; run-time  -- ) \ gforth
     POSTPONE then ; immediate compile-only      \G Starts restoring code, that is executed if there is an
       \G exception, and if there is no exception.
       POSTPONE iferror POSTPONE then
   ; immediate compile-only
   
   : endtry ( compilation  -- ; run-time  R:sys1 -- ) \ gforth
       \G End an exception-catching region.
       POSTPONE (endtry)
   ; immediate compile-only
   
   : endtry-iferror ( compilation  orig1 -- orig2 ; run-time  R:sys1 -- ) \ gforth
       \G End an exception-catching region while starting
       \G exception-handling code outside that region (executed if there
       \G is an exception between @code{try} and @code{endtry-iferror}).
       \G This part has to be finished with @code{then} (or
       \G @code{else}...@code{then}).
       POSTPONE (endtry) POSTPONE iferror POSTPONE (endtry)
   ; immediate compile-only
   
 :noname ( x1 .. xn xt -- y1 .. ym 0 / z1 .. zn error ) \ exception  :noname ( x1 .. xn xt -- y1 .. ym 0 / z1 .. zn error ) \ exception
     try      try
         execute 0          execute 0
     recover      iferror
         nip          nip
     endtry ;      then endtry ;
 is catch  is catch
   
 :noname ( y1 .. ym error/0 -- y1 .. ym / z1 .. zn error ) \ exception  :noname ( y1 .. ym error/0 -- y1 .. ym / z1 .. zn error ) \ exception
     ?DUP IF      ?DUP IF
         [ here forthstart 9 cells + ! ]          [ here forthstart 9 cells + ! ]
         store-backtrace error-stack off          first-throw @ IF
         handler @ ?dup-0=-IF              store-backtrace error-stack off
             >stderr cr ." uncaught exception: " .error cr              first-throw off
             2 (bye)  
 \           quit  
         THEN          THEN
         rp!  
         r> handler !  
         r> lp!  
         r> fp!  
         r> swap >r sp! drop r>  
         rdrop 'throw r> perform  
     THEN ;  
 is throw  
 [IFDEF] throw>error  
 :noname ( y1 .. ym error/0 -- y1 .. ym / z1 .. zn error ) \ exception  
     ?DUP IF  
         handler @ ?dup-0=-IF          handler @ ?dup-0=-IF
             >stderr cr ." uncaught exception: " .error cr              >stderr cr ." uncaught exception: " .error cr
             2 (bye)              2 (bye)
 \           quit  \           quit
         THEN          THEN
         rp!          dup rp! ( ... ball frame )
         r> handler !          cell+ dup @ lp!
         r> lp!          cell+ dup @ fp!
         r> fp!          cell+ dup @ ( ... ball addr sp ) -rot 2>r sp! drop 2r>
         r> swap >r sp! drop r>          cell+ @ perform
         rdrop 'throw r> perform  
     THEN ;      THEN ;
 is throw>error  
 [THEN]  
   
   is throw

Removed from v.1.10  
changed lines
  Added in v.1.19


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