--- gforth/glocals.fs 1996/09/19 22:17:31 1.26 +++ gforth/glocals.fs 2007/07/06 12:54:56 1.58 @@ -1,6 +1,6 @@ \ A powerful locals implementation -\ Copyright (C) 1995 Free Software Foundation, Inc. +\ Copyright (C) 1995,1996,1997,1998,2000,2003,2004,2005 Free Software Foundation, Inc. \ This file is part of Gforth. @@ -16,7 +16,7 @@ \ 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. +\ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. \ More documentation can be found in the manual and in @@ -85,8 +85,9 @@ \ Currently locals may only be \ defined at the outer level and TO is not supported. -require search-order.fs +require search.fs require float.fs +require extend.fs \ for case : compile-@local ( n -- ) \ gforth compile-fetch-local case @@ -104,6 +105,21 @@ require float.fs ( otherwise ) dup postpone f@local# , 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) \ 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. @@ -114,7 +130,7 @@ require float.fs slowvoc @ slowvoc on \ we want a linked list for the vocabulary locals vocabulary locals \ this contains the local variables -' locals >body ' locals-list >body ! +' locals >body wordlist-id ' locals-list >body ! slowvoc ! create locals-buffer 1000 allot \ !! limited and unsafe @@ -142,6 +158,55 @@ variable locals-dp \ so here's the speci swap ! 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 -- ) locals-size @ alignlp-f float+ dup locals-size ! swap ! @@ -228,26 +293,45 @@ locals-types definitions postpone laddr# @ lp-offset, ; \ you may want to make comments in a locals definitions group: -' \ alias \ immediate -' ( alias ( immediate +' \ alias \ ( compilation 'ccc' -- ; run-time -- ) \ core-ext,block-ext backslash +\G Comment till the end of the line if @code{BLK} contains 0 (i.e., +\G while not loading a block), parse and discard the remainder of the +\G parse area. Otherwise, parse and discard all subsequent characters +\G in the parse area corresponding to the current line. +immediate + +' ( alias ( ( compilation 'ccc' -- ; run-time -- ) \ core,file paren +\G Comment, usually till the next @code{)}: parse and discard all +\G subsequent characters in the parse area until ")" is +\G encountered. During interactive input, an end-of-line also acts as +\G a comment terminator. For file input, it does not; if the +\G end-of-file is encountered whilst parsing for the ")" delimiter, +\G Gforth will generate a warning. +immediate forth definitions +also locals-types + +\ these "locals" are used for comparison in TO +c: some-clocal 2drop +d: some-dlocal 2drop +f: some-flocal 2drop +w: some-wlocal 2drop + \ the following gymnastics are for declaring locals without type specifier. \ we exploit a feature of our dictionary: every wordlist \ has it's own methods for finding words etc. \ So we create a vocabulary new-locals, that creates a 'w:' local named x \ when it is asked if it contains x. -also locals-types - : new-locals-find ( caddr u w -- nfa ) \ this is the find method of the new-locals vocabulary \ make a new local with name caddr u; w is ignored \ the returned nfa denotes a word that produces what W: produces \ !! do the whole thing without nextname drop nextname - ['] W: >name ; + ['] W: >head-noprim ; previous @@ -255,25 +339,34 @@ previous true abort" this should not happen: new-locals-reveal" ; create new-locals-map ( -- wordlist-map ) -' new-locals-find A, ' new-locals-reveal A, - -vocabulary new-locals -new-locals-map ' new-locals >body cell+ A! \ !! use special access words +' new-locals-find A, +' new-locals-reveal A, +' drop A, \ rehash method +' drop A, + +new-locals-map mappedwordlist Constant new-locals-wl + +\ slowvoc @ +\ slowvoc on +\ vocabulary new-locals +\ slowvoc ! +\ new-locals-map ' new-locals >body wordlist-map A! \ !! use special access words variable old-dpp \ and now, finally, the user interface words -: { ( -- addr wid 0 ) \ gforth open-brace +: { ( -- latestxt wid 0 ) \ gforth open-brace dp old-dpp ! locals-dp dpp ! - also new-locals - also get-current locals definitions locals-types + latestxt get-current + get-order new-locals-wl swap 1+ set-order + also locals definitions locals-types 0 TO locals-wordlist 0 postpone [ ; immediate locals-types definitions -: } ( addr wid 0 a-addr1 xt1 ... -- ) \ gforth close-brace +: } ( latestxt wid 0 a-addr1 xt1 ... -- ) \ gforth close-brace \ ends locals definitions ] old-dpp @ dpp ! begin @@ -283,9 +376,9 @@ locals-types definitions repeat drop locals-size @ alignlp-f locals-size ! \ the strictest alignment - set-current previous previous - locals-list TO locals-wordlist ; + set-current lastcfa ! + locals-list 0 wordlist-id - TO locals-wordlist ; : -- ( addr wid 0 ... -- ) \ gforth dash-dash } @@ -381,39 +474,28 @@ forth definitions \ If this assumption is too optimistic, the compiler will warn the user. -\ Implementation: migrated to kernel.fs - -\ 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) -\ : -\ 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 . +\ Implementation: \ explicit scoping : scope ( compilation -- scope ; run-time -- ) \ gforth - cs-push-part scopestart ; immediate + cs-push-part scopestart ; immediate + +: adjust-locals-list ( wid -- ) + locals-list @ common-list + dup list-size adjust-locals-size + locals-list ! ; : endscope ( compilation scope -- ; run-time -- ) \ gforth - scope? - drop - locals-list @ common-list - dup list-size adjust-locals-size - locals-list ! ; immediate + scope? + drop adjust-locals-list ; immediate \ adapt the hooks : locals-:-hook ( sys -- sys addr xt n ) \ addr is the nfa of the defined word, xt its xt DEFERS :-hook - last @ lastcfa @ + latest latestxt clear-leave-stack 0 locals-size ! locals-buffer locals-dp ! @@ -428,9 +510,84 @@ forth definitions lastcfa ! last ! 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) +\ : +\ 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-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 + adjust-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 + +: (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+!# (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 compile, drop + then ( list ) + check-begin ; + +: (exit-like) ( -- ) + 0 adjust-locals-size ; + ' 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 \ of the current word. This is a bit too conservative, but very simple. @@ -441,10 +598,6 @@ forth definitions \ things above are not control flow joins. Everything should be taken \ 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: \ 1) Do not complain (After all, this is Forth;-) @@ -485,20 +638,21 @@ forth definitions 2drop endif ; -: >definer ( xt -- definer ) - \ this gives a unique identifier for the way the xt was defined - \ words defined with different does>-codes have different definers - \ the definer can be used for comparison and in definer! - dup >code-address [ ' spaces >code-address ] Literal = - \ !! this definition will not work on some implementations for `bits' - if \ if >code-address delivers the same value for all does>-def'd words - >does-code 1 or \ bit 0 marks special treatment for does codes +: >definer ( xt -- definer ) \ gforth + \G @var{Definer} is a unique identifier for the way the @var{xt} + \G was defined. Words defined with different @code{does>}-codes + \G have different definers. The definer can be used for + \G comparison and in @code{definer!}. + dup >does-code + ?dup-if + nip 1 or else >code-address then ; -: definer! ( definer xt -- ) - \ gives the word represented by xt the behaviour associated with definer +: definer! ( definer xt -- ) \ gforth + \G The word represented by @var{xt} changes its behaviour to the + \G behaviour associated with @var{definer}. over 1 and if swap [ 1 invert ] literal and does-code! else @@ -506,35 +660,37 @@ forth definitions then ; :noname - ' dup >definer [ ' locals-wordlist >definer ] literal = + ' dup >definer [ ' locals-wordlist ] literal >definer = if >body ! else -&32 throw endif ; :noname - 0 0 0. 0.0e0 { c: clocal w: wlocal d: dlocal f: flocal } - ' dup >definer + comp' drop dup >definer case - [ ' locals-wordlist >definer ] literal \ value + [ ' locals-wordlist ] literal >definer \ value OF >body POSTPONE Aliteral POSTPONE ! ENDOF - [ comp' clocal drop >definer ] literal + \ !! dependent on c: etc. being does>-defining words + \ this works, because >definer uses >does-code in this case, + \ which produces a relocatable address + [ comp' some-clocal drop ] literal >definer OF POSTPONE laddr# >body @ lp-offset, POSTPONE c! ENDOF - [ comp' wlocal drop >definer ] literal + [ comp' some-wlocal drop ] literal >definer OF POSTPONE laddr# >body @ lp-offset, POSTPONE ! ENDOF - [ comp' dlocal drop >definer ] literal + [ comp' some-dlocal drop ] literal >definer OF POSTPONE laddr# >body @ lp-offset, POSTPONE 2! ENDOF - [ comp' flocal drop >definer ] literal + [ comp' some-flocal drop ] literal >definer OF POSTPONE laddr# >body @ lp-offset, POSTPONE f! ENDOF -&32 throw endcase ; interpret/compile: TO ( c|w|d|r "name" -- ) \ core-ext,local -: locals| +: locals| ( ... "name ..." -- ) \ local-ext locals-bar \ don't use 'locals|'! use '{'! A portable and free '{' \ implementation is compat/anslocals.fs BEGIN - name 2dup s" |" compare 0<> + name 2dup s" |" str= 0= WHILE (local) REPEAT