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Diff for /gforth/glocals.fs between versions 1.27 and 1.28

version 1.27, 1996/09/24 19:15:02 version 1.28, 1996/09/30 13:16:10
Line 448  forth definitions Line 448  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 kernel.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
   
Line 495  forth definitions Line 482  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 -- addr )  : (then-like) ( orig -- addr )
     swap -rot dead-orig =      swap -rot dead-orig =
     if      if
Line 570  forth definitions Line 570  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 643  forth definitions Line 639  forth definitions
     endif ;      endif ;
 :noname  :noname
     0 0 0. 0.0e0 { c: clocal w: wlocal d: dlocal f: flocal }      0 0 0. 0.0e0 { c: clocal w: wlocal d: dlocal f: flocal }
     ' dup >definer      comp' drop dup >definer
     case      case
         [ ' locals-wordlist >definer ] literal \ value          [ ' locals-wordlist >definer ] literal \ value
         OF >body POSTPONE Aliteral POSTPONE ! ENDOF          OF >body POSTPONE Aliteral POSTPONE ! ENDOF
Removed from v.1.27  
changed lines
  Added in v.1.28

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