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Add some comments around search order, find and removing words on forget or clear.

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This commit is contained in:
Philip Zembrod 2020-12-05 17:39:42 +01:00
parent 4186b42cbb
commit 3db4ae726c
1 changed files with 32 additions and 6 deletions
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38
6502/C64/src/vf-cbm-core.fth
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@ -1810,6 +1810,13 @@ Variable ?heapmovetx 0 ?heapmovetx !
( voc-link vp current context also bp)
\ vp contains the vocabulary search oder respectively stack.
\ vp/vp+1: order/stack size. 0 = one vocabulary on the stack
\ vp+2/vp+3: bottom vocabulary on the stack
\ ...
\ vp+N+2/vp+N+3: the current context vocabulary, the top of stack,
\ if N is the content of vp/vp+1.
\ The top two vocabularies are the same after also is called.
Create vp $10 allot
Variable current
@ -1953,6 +1960,8 @@ Label findloop 0 # ldy
( find ' ['] 13jan85bp)
: find ( string -- cfa n / string false)
\ Skip the top vocabulary in the search order if it's equal to the
\ second in the search order, as is the case after also is called.
context dup @ over 2- @ = IF 2- THEN
BEGIN under @ (find
IF nip found exit THEN
@ -2418,23 +2427,40 @@ Defer init-buffers ' noop IS init-buffers
\ remove 23jul85we
| Code remove ( dic symb thr - dic symb)
| Code remove ( dict symb thread - dict symb)
\ thread: vocabulary linked list
5 # ldy [[ SP )Y lda N ,Y sta dey 0< ?]
\ N+4/5: dict N+2/3: symb N+0/1: thread
user' s0 # ldy
clc UP )Y lda 6 # adc N 6 + sta
iny UP )Y lda 0 # adc N 7 + sta
1 # ldy
\ N+6/7: s0
[[ N X) lda N 8 + sta
N )Y lda N 9 + sta N 8 + ora 0<>
\ N+8/9: next ptr in thread
\ compare N+8/9 next ptr to s0 in N+6/7:
?[[ N 8 + lda N 6 + cmp
N 9 + lda N 7 + sbc CS
\ CS aka u>= :
\ compare N+8/9 next ptr to symb N+2/3
?[ N 8 + lda N 2 + cmp
N 9 + lda N 3 + sbc
\ CC aka u< :
\ compare N+4/5 dict to next ptr N+8/9
][ N 4 + lda N 8 + cmp
N 5 + lda N 9 + sbc
]? CC
\ CC aka u< i.e.
\ either (CS above) s0 u<= next ptr u< symb
\ or (CC above) dict u< next ptr u< s0
\ let current ptr's adr point to next ptr's adr,
\ i.e. remover next ptr from vocabulary thread.
?[ N 8 + X) lda N X) sta
N 8 + )Y lda N )Y sta
\ CS aka u>= :
\ let next ptr N+8/9 be current ptr N+0/1
\ i.e. leave next ptr in vocabulary thread.
][ N 8 + lda N sta
N 9 + lda N 1+ sta ]?
]]? (drop jmp end-code
@ -2447,17 +2473,17 @@ Defer init-buffers ' noop IS init-buffers
( remove- forget-words 29apr85bp)
| : remove-words ( dic symb -- dic symb)
| : remove-words ( dict symb -- dict symb)
voc-link BEGIN @ ?dup
WHILE dup >r 4 - remove r> REPEAT ;
| : remove-tasks ( dic --)
| : remove-tasks ( dict --)
up@ BEGIN 1+ dup @ up@ -
WHILE 2dup @ swap here uwithin
IF dup @ 1+ @ over ! 1- ELSE @ THEN
REPEAT 2drop ;
| : remove-vocs ( dic symb -- dic symb)
| : remove-vocs ( dict symb -- dict symb)
voc-link remove thru.vocstack
DO 2dup I @ -rot uwithin
IF [ ' Forth 2+ ] Literal I ! THEN
@ -2476,11 +2502,11 @@ Defer custom-remove
( deleting words from dict. 13jan83ks)
: (forget-words ( dic symb -- dic symb )
: (forget-words ( dict symb -- dict symb )
over remove-tasks remove-vocs
remove-words custom-remove ;
| : forget-words ( dic symb --)
| : forget-words ( dict symb --)
(forget-words
heap swap - hallot dp ! 0 last ! ;