\ exception   10/04/97   gwj
\ an implementation of the ANS Forth
\ exception wordset
create exception

create  handler  0 , 0 ,

: catch  ( xt -- exception# | 0 )
    sp@ >r >r
    handler 2@ >r >r
    rp@ handler 2!
    execute
    r> r> handler 2!
    r> r> 2drop
    0
  ;

: throw ( ??? xcptn# -- ??? xcptn# )
   ?dup if
       handler 2@ or 0=
       if    dup -1 <> and dup -2 <> and
              dup
              if   ." Unhandled exception#" .
              then abort
       else handler 2@ rp!
              r> r> handler 2!
              r> r> rot >r
              sp! drop r>
       then
   then
  ;

: abort   ( -- )    -1 throw ;
: abortq   ( addr cnt -- ) 
cr type -2 throw ;
: abort"  ( "ccc<">" -- )
    postpone s" postpone abortq ; immediate