version 1.12, 1995/04/29 14:51:19
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version 1.44, 2000/08/09 20:04:05
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\ A powerful locals implementation |
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\ Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc. |
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\ This file is part of Gforth. |
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\ Gforth is free software; you can redistribute it and/or |
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\ modify it under the terms of the GNU General Public License |
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\ as published by the Free Software Foundation; either version 2 |
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\ of the License, or (at your option) any later version. |
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\ This program is distributed in the hope that it will be useful, |
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\ but WITHOUT ANY WARRANTY; without even the implied warranty of |
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\ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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\ GNU General Public License for more details. |
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\ You should have received a copy of the GNU General Public License |
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\ along with this program; if not, write to the Free Software |
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\ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
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\ More documentation can be found in the manual and in |
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\ http://www.complang.tuwien.ac.at/papers/ertl94l.ps.gz |
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\ 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. |
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\ 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. |
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include search-order.fs |
require search.fs |
include float.fs |
require float.fs |
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: 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
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Line 97 include float.fs
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( otherwise ) dup postpone @local# , |
( otherwise ) dup postpone @local# , |
endcase ; |
endcase ; |
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: 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 ; |
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\ locals stuff needed for control structures |
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: compile-lp+! ( n -- ) \ gforth compile-l-p-plus-store |
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dup negate locals-size +! |
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0 over = if |
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else -1 cells over = if postpone lp- |
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else 1 floats over = if postpone lp+ |
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else 2 floats over = if postpone lp+2 |
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else postpone lp+!# dup , |
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then then then then drop ; |
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: adjust-locals-size ( n -- ) \ gforth |
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\ sets locals-size to n and generates an appropriate lp+! |
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locals-size @ swap - compile-lp+! ; |
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\ 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 90 include float.fs
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Line 129 include float.fs
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slowvoc @ |
slowvoc @ |
slowvoc on \ we want a linked list for the vocabulary locals |
slowvoc on \ we want a linked list for the vocabulary locals |
vocabulary locals \ this contains the local variables |
vocabulary locals \ this contains the local variables |
' locals >body ' locals-list >body ! |
' locals >body wordlist-id ' locals-list >body ! |
slowvoc ! |
slowvoc ! |
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create locals-buffer 1000 allot \ !! limited and unsafe |
create locals-buffer 1000 allot \ !! limited and unsafe |
Line 118 variable locals-dp \ so here's the speci
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Line 157 variable locals-dp \ so here's the speci
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swap ! |
swap ! |
postpone >l ; |
postpone >l ; |
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\ locals list operations |
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: common-list ( list1 list2 -- list3 ) \ gforth-internal |
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\ list1 and list2 are lists, where the heads are at higher addresses than |
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\ the tail. list3 is the largest sublist of both lists. |
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begin |
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2dup u<> |
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while |
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2dup u> |
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if |
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swap |
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then |
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@ |
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repeat |
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drop ; |
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: sub-list? ( list1 list2 -- f ) \ gforth-internal |
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\ true iff list1 is a sublist of list2 |
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begin |
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2dup u< |
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while |
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@ |
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repeat |
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= ; |
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: list-size ( list -- u ) \ gforth-internal |
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\ size of the locals frame represented by list |
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0 ( list n ) |
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begin |
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over 0<> |
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while |
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over |
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((name>)) >body @ max |
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swap @ swap ( get next ) |
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repeat |
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faligned nip ; |
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: set-locals-size-list ( list -- ) |
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dup locals-list ! |
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list-size locals-size ! ; |
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: check-begin ( list -- ) |
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\ warn if list is not a sublist of locals-list |
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locals-list @ sub-list? 0= if |
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\ !! print current position |
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." compiler was overly optimistic about locals at a BEGIN" cr |
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\ !! print assumption and reality |
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then ; |
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: 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
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Line 241 variable locals-dp \ so here's the speci
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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 |
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: 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 ; |
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: 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, ; |
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: 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 ; |
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: 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, ; |
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: 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@ ; |
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: 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, ; |
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: 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@ ; |
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: 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, ; |
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\ you may want to make comments in a locals definitions group: |
\ you may want to make comments in a locals definitions group: |
' \ alias \ immediate |
' \ alias \ ( compilation 'ccc<newline>' -- ; run-time -- ) \ core-ext,block-ext backslash |
' ( alias ( immediate |
\G Comment till the end of the line if @code{BLK} contains 0 (i.e., |
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\G while not loading a block), parse and discard the remainder of the |
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\G parse area. Otherwise, parse and discard all subsequent characters |
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\G in the parse area corresponding to the current line. |
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immediate |
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' ( alias ( ( compilation 'ccc<close-paren>' -- ; run-time -- ) \ core,file paren |
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\G Comment, usually till the next @code{)}: parse and discard all |
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\G subsequent characters in the parse area until ")" is |
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\G encountered. During interactive input, an end-of-line also acts as |
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\G a comment terminator. For file input, it does not; if the |
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\G end-of-file is encountered whilst parsing for the ")" delimiter, |
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\G Gforth will generate a warning. |
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immediate |
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forth definitions |
forth definitions |
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Line 223 also locals-types
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Line 324 also locals-types
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\ the returned nfa denotes a word that produces what W: produces |
\ the returned nfa denotes a word that produces what W: produces |
\ !! do the whole thing without nextname |
\ !! do the whole thing without nextname |
drop nextname |
drop nextname |
['] W: >name ; |
['] W: >head-noprim ; |
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previous |
previous |
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: new-locals-reveal ( -- ) |
: new-locals-reveal ( -- ) |
true abort" this should not happen: new-locals-reveal" ; |
true abort" this should not happen: new-locals-reveal" ; |
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create new-locals-map ' new-locals-find A, ' new-locals-reveal A, |
create new-locals-map ( -- wordlist-map ) |
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' new-locals-find A, |
vocabulary new-locals |
' new-locals-reveal A, |
new-locals-map ' new-locals >body cell+ A! \ !! use special access words |
' drop A, \ rehash method |
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' drop A, |
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new-locals-map mappedwordlist Constant new-locals-wl |
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\ slowvoc @ |
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\ slowvoc on |
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\ vocabulary new-locals |
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\ slowvoc ! |
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\ new-locals-map ' new-locals >body wordlist-map A! \ !! use special access words |
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variable old-dpp |
variable old-dpp |
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\ 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 ! |
also new-locals |
lastxt get-current |
also get-current locals definitions locals-types |
get-order new-locals-wl swap 1+ set-order |
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also locals definitions locals-types |
0 TO locals-wordlist |
0 TO locals-wordlist |
0 postpone [ ; immediate |
0 postpone [ ; immediate |
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locals-types definitions |
locals-types definitions |
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: } ( 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
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Line 369 locals-types definitions
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repeat |
repeat |
drop |
drop |
locals-size @ alignlp-f locals-size ! \ the strictest alignment |
locals-size @ alignlp-f locals-size ! \ the strictest alignment |
set-current |
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previous previous |
previous previous |
locals-list TO locals-wordlist ; |
set-current lastcfa ! |
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locals-list 0 wordlist-id - TO locals-wordlist ; |
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: -- ( addr wid 0 ... -- ) |
: -- ( addr wid 0 ... -- ) \ gforth dash-dash |
} |
} |
[char] } parse 2drop ; |
[char] } parse 2drop ; |
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Line 356 forth definitions
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Line 467 forth definitions
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\ If this assumption is too optimistic, the compiler will warn the user. |
\ If this assumption is too optimistic, the compiler will warn the user. |
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\ Implementation: migrated to kernal.fs |
\ Implementation: |
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\ THEN (another control flow from before joins the current one): |
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\ The new locals-list is the intersection of the current locals-list and |
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\ the orig-local-list. The new locals-size is the (alignment-adjusted) |
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\ size of the new locals-list. The following code is generated: |
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\ lp+!# (current-locals-size - orig-locals-size) |
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\ <then>: |
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\ lp+!# (orig-locals-size - new-locals-size) |
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\ Of course "lp+!# 0" is not generated. Still this is admittedly a bit |
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\ inefficient, e.g. if there is a locals declaration between IF and |
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\ ELSE. However, if ELSE generates an appropriate "lp+!#" before the |
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\ branch, there will be none after the target <then>. |
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\ explicit scoping |
\ explicit scoping |
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: scope ( -- scope ) |
: scope ( compilation -- scope ; run-time -- ) \ gforth |
cs-push-part scopestart ; immediate |
cs-push-part scopestart ; immediate |
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: endscope ( scope -- ) |
: adjust-locals-list ( wid -- ) |
scope? |
locals-list @ common-list |
drop |
dup list-size adjust-locals-size |
locals-list @ common-list |
locals-list ! ; |
dup list-size adjust-locals-size |
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locals-list ! ; immediate |
: endscope ( compilation scope -- ; run-time -- ) \ gforth |
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scope? |
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drop adjust-locals-list ; immediate |
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\ adapt the hooks |
\ adapt the hooks |
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Line 403 forth definitions
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Line 503 forth definitions
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lastcfa ! last ! |
lastcfa ! last ! |
DEFERS ;-hook ; |
DEFERS ;-hook ; |
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\ THEN (another control flow from before joins the current one): |
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\ The new locals-list is the intersection of the current locals-list and |
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\ the orig-local-list. The new locals-size is the (alignment-adjusted) |
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\ size of the new locals-list. The following code is generated: |
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\ lp+!# (current-locals-size - orig-locals-size) |
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\ <then>: |
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\ lp+!# (orig-locals-size - new-locals-size) |
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\ Of course "lp+!# 0" is not generated. Still this is admittedly a bit |
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\ inefficient, e.g. if there is a locals declaration between IF and |
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\ ELSE. However, if ELSE generates an appropriate "lp+!#" before the |
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\ branch, there will be none after the target <then>. |
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: (then-like) ( orig -- ) |
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dead-orig = |
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if |
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>resolve drop |
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else |
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dead-code @ |
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if |
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>resolve set-locals-size-list dead-code off |
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else \ both live |
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over list-size adjust-locals-size |
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>resolve |
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adjust-locals-list |
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then |
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then ; |
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: (begin-like) ( -- ) |
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dead-code @ if |
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\ set up an assumption of the locals visible here. if the |
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\ users want something to be visible, they have to declare |
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\ that using ASSUME-LIVE |
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backedge-locals @ set-locals-size-list |
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then |
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dead-code off ; |
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\ AGAIN (the current control flow joins another, earlier one): |
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\ If the dest-locals-list is not a subset of the current locals-list, |
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\ issue a warning (see below). The following code is generated: |
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\ lp+!# (current-local-size - dest-locals-size) |
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\ branch <begin> |
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: (again-like) ( dest -- addr ) |
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over list-size adjust-locals-size |
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swap check-begin POSTPONE unreachable ; |
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\ UNTIL (the current control flow may join an earlier one or continue): |
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\ Similar to AGAIN. The new locals-list and locals-size are the current |
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\ ones. The following code is generated: |
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\ ?branch-lp+!# <begin> (current-local-size - dest-locals-size) |
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: (until-like) ( list addr xt1 xt2 -- ) |
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\ list and addr are a fragment of a cs-item |
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\ xt1 is the conditional branch without lp adjustment, xt2 is with |
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>r >r |
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locals-size @ 2 pick list-size - dup if ( list dest-addr adjustment ) |
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r> drop r> compile, |
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swap <resolve ( list adjustment ) , |
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else ( list dest-addr adjustment ) |
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drop |
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r> compile, <resolve |
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r> drop |
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then ( list ) |
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check-begin ; |
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: (exit-like) ( -- ) |
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0 adjust-locals-size ; |
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' locals-:-hook IS :-hook |
' locals-:-hook IS :-hook |
' locals-;-hook IS ;-hook |
' locals-;-hook IS ;-hook |
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' (then-like) IS then-like |
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' (begin-like) IS begin-like |
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' (again-like) IS again-like |
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' (until-like) IS until-like |
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' (exit-like) IS exit-like |
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\ 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. |
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Line 416 forth definitions
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Line 591 forth definitions
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\ 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. |
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\ !! The lp gymnastics for UNTIL are also a real problem: locals cannot be |
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\ used in signal handlers (or anything else that may be called while |
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\ locals live beyond the lp) without changing the locals stack. |
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\ About warning against uses of dead locals. There are several options: |
\ About warning against uses of dead locals. There are several options: |
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\ 1) Do not complain (After all, this is Forth;-) |
\ 1) Do not complain (After all, this is Forth;-) |
Line 449 forth definitions
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Line 620 forth definitions
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\ And here's finally the ANS standard stuff |
\ And here's finally the ANS standard stuff |
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: (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
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Line 635 forth definitions
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\ 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 |
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else |
else |
>code-address |
>code-address |
then ; |
then ; |
Line 475 forth definitions
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Line 645 forth definitions
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: 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 ; |
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\ !! 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 |
\ !! dependent on c: etc. being does>-defining words |
[ ' dlocal >definer ] literal |
\ this works, because >definer uses >does-code in this case, |
OF POSTPONE laddr# >body @ lp-offset, POSTPONE d! ENDOF |
\ which produces a relocatable address |
[ ' flocal >definer ] literal |
[ comp' clocal drop >definer ] literal |
OF POSTPONE laddr# >body @ lp-offset, POSTPONE f! ENDOF |
OF POSTPONE laddr# >body @ lp-offset, POSTPONE c! ENDOF |
-&32 throw |
[ comp' wlocal drop >definer ] literal |
endcase |
OF POSTPONE laddr# >body @ lp-offset, POSTPONE ! ENDOF |
else |
[ comp' dlocal drop >definer ] literal |
[ ' locals-wordlist >definer ] literal = |
OF POSTPONE laddr# >body @ lp-offset, POSTPONE 2! ENDOF |
if |
[ comp' flocal drop >definer ] literal |
>body ! |
OF POSTPONE laddr# >body @ lp-offset, POSTPONE f! ENDOF |
else |
-&32 throw |
-&32 throw |
endcase ; |
endif |
interpret/compile: TO ( c|w|d|r "name" -- ) \ core-ext,local |
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 |