include term-colours.4th
include defer-is.4th
+include goto.4th
include catch-throw.4th
+include integer.4th
include float.4th
include debugging.4th
defer read
+defer expand
+defer analyze
defer eval
defer print
make-type fixnum-type
make-type flonum-type
+make-type ratnum-type
make-type boolean-type
make-type character-type
make-type string-type
make-type symbol-type
make-type primitive-proc-type
make-type compound-proc-type
-make-type fileport-type
+make-type continuation-type
+make-type port-type
: istype? ( obj type -- obj bool )
over = ;
1 nextexception +!
does> @ ;
-make-exception recoverable-exception
-make-exception unrecoverable-exception
-
-: display-exception-msg ( addr count -- )
+: except-message:
bold fg red
." Exception: "
- type
- reset-term ;
-
-: throw" immediate
- [compile] s"
-
- ['] rot , ['] dup ,
+;
- [compile] if
- ['] -rot ,
- ['] display-exception-msg ,
- [compile] then
+make-exception recoverable-exception
+make-exception unrecoverable-exception
- ['] throw ,
-;
+: throw reset-term cr throw ;
\ }}}
\ ---- List-structured memory ---- {{{
-10000 constant scheme-memsize
+20000 constant scheme-memsize
create car-cells scheme-memsize allot
create car-type-cells scheme-memsize allot
nextfree !
nextfree @ scheme-memsize >= if
- collect-garbage
+ collect-garbage
then
nextfree @ scheme-memsize >= if
- unrecoverable-exception throw s" Out of memory!"
+ except-message: ." Out of memory!" unrecoverable-exception throw
then
;
cdr-cells + !
;
+variable object-stack-base
+: init-object-stack-base
+ depth object-stack-base ! ;
+
: nil 0 nil-type ;
: nil? nil-type istype? ;
R> R>
;
-\ }}}
-
-\ ---- Port I/O ---- {{{
-
-: fileport>fid ( fileport -- fid )
- drop ;
-
-: fid>fileport ( fid -- fileport )
- fileport-type ;
-
-: open-input-file ( addr n -- fileport )
- r/o open-file drop fid>fileport
-;
-
-: close-port ( fileport -- )
- fileport>fid close-file drop
-;
-
-objvar console-i/o-port
-0 fileport-type console-i/o-port obj!
-
-objvar current-input-port
-console-i/o-port obj@ current-input-port obj!
-
-: read-port ( fileport -- obj )
- current-input-port obj!
- read ;
-
-: read-console ( -- obj )
- console-i/o-port obj@ read-port ;
+: 2pick ( an bn an-1 bn-1 ... a0 b0 n -- an bn an-1 bn-1 ... a0 b0 an bn )
+ 2* 1+ dup
+ >R pick R> pick ;
\ }}}
create-symbol if if-symbol
create-symbol lambda lambda-symbol
create-symbol λ λ-symbol
-create-symbol begin begin-symbol
+create-symbol eof eof-symbol
+create-symbol no-match no-match-symbol
+
+\ Symbol to be bound to welcome message procedure by library
+create-symbol welcome welcome-symbol
+
+\ }}}
+
+\ ---- Port I/O ---- {{{
+
+( Ports are pairs with the fid in the car and the peek buffer in the cdr. )
+
+: fileport>fid ( fileport -- fid )
+ drop pair-type car drop ;
+
+: get-last-peek ( fileport -- char/nil )
+ drop pair-type cdr ;
+
+: set-last-peek ( char/nil fileport -- )
+ drop pair-type set-cdr!
+;
+
+: fid>fileport ( fid -- fileport )
+ fixnum-type nil cons drop port-type ;
+
+: open-input-file ( addr n -- fileport )
+ r/o open-file drop fid>fileport
+;
+
+: close-port ( fileport -- )
+ fileport>fid close-file drop
+;
+
+objvar console-i/o-port
+0 fixnum-type nil cons drop port-type console-i/o-port obj!
+
+objvar current-input-port
+console-i/o-port obj@ current-input-port obj!
+
+: read-char ( port -- char )
+ 2dup get-last-peek nil? if
+ 2drop
+ 2dup console-i/o-port obj@ objeq? if
+ 2drop
+ key character-type
+ else
+ fileport>fid pad 1 rot read-file 0= if
+ eof-symbol
+ else
+ pad @ character-type
+ then
+ then
+ else
+ nil 2rot set-cdr!
+ then
+;
+
+: peek-char ( port -- char )
+ 2dup get-last-peek nil? if
+ 2drop 2dup read-char
+ 2dup 2rot set-last-peek
+ else
+ 2swap 2drop
+ then
+;
+
+variable read-line-buffer-span
+variable read-line-buffer-offset
+
+( Hack to save original read-line while we transition to new one. )
+: orig-read-line immediate
+ ['] read-line , ;
+
+: read-line ( port -- string )
+
+ 2dup get-last-peek
+ nil? if
+ 2drop
+ 0 read-line-buffer-offset !
+ else
+ 2over nil 2swap set-last-peek
+ 2dup drop '\n' = if
+ 2drop nil nil cons exit
+ else
+ drop pad !
+ 1 read-line-buffer-offset !
+ then
+ then
+
+ 2dup console-i/o-port obj@ objeq? if
+ 2drop
+ pad read-line-buffer-offset @ + 200 expect cr
+ span @ read-line-buffer-offset @ + read-line-buffer-span !
+ else
+ pad read-line-buffer-offset @ + 200 2over fileport>fid orig-read-line
+ drop swap read-line-buffer-offset @ + read-line-buffer-span !
+ then
+
+ nil
+
+ begin
+ read-line-buffer-span @ 0>
+ while
+ pad read-line-buffer-span @ 1- + @ character-type 2swap cons
+ -1 read-line-buffer-span +!
+ repeat
+
+ nil? if
+ nil cons drop string-type
+ else
+ drop string-type
+ then
+;
+
+: read-port ( fileport -- obj )
+ current-input-port obj!
+ read ;
+
+: read-console ( -- obj )
+ console-i/o-port obj@ read-port ;
\ }}}
: make-frame ( vars vals -- frame )
cons ;
+: add-frame-to-env ( frame env -- env )
+ cons ;
+
: frame-vars ( frame -- vars )
car ;
;
: extend-env ( vars vals env -- env )
- >R >R
- make-frame
- R> R>
- cons
+ -2rot make-frame
+ 2swap add-frame-to-env
;
-objvar vars
-objvar vals
-
-: get-vars-vals-frame ( var frame -- bool )
- 2dup frame-vars vars obj!
- frame-vals vals obj!
+: get-vals-frame ( var frame -- vals | nil )
+ 2dup frame-vars
+ 2swap frame-vals ( var vars vals )
begin
- vars obj@ nil objeq? false =
+ nil? false =
while
- 2dup vars obj@ car objeq? if
- 2drop true
+
+ -2rot ( vals var vars )
+ 2over 2over car objeq? if
+ 2drop 2drop
exit
then
- vars obj@ cdr vars obj!
- vals obj@ cdr vals obj!
+ cdr 2rot cdr
repeat
- 2drop false
+ 2drop 2drop 2drop
+ nil
;
-: get-vars-vals ( var env -- vars? vals? bool )
+: get-vals ( var env -- vals | nil )
begin
nil? false =
while
2over 2over first-frame
- get-vars-vals-frame if
- 2drop 2drop
- vars obj@ vals obj@ true
+ get-vals-frame nil? false = if
+ 2swap 2drop 2swap 2drop
exit
then
+ 2drop
+
enclosing-env
repeat
- 2drop 2drop
- false
+ 2swap 2drop
;
-hide vars
-hide vals
-
+objvar var \ Used only for error messages
: lookup-var ( var env -- val )
- get-vars-vals if
- 2swap 2drop car
- else
- recoverable-exception throw" Tried to read unbound variable."
+ 2over var obj!
+
+ get-vals nil? if
+ except-message: ." tried to read unbound variable '" var obj@ print ." '."
+ recoverable-exception throw
then
+
+ car
;
: set-var ( var val env -- )
- >R >R 2swap R> R> ( val var env )
- get-vars-vals if
- 2swap 2drop ( val vals )
- set-car!
+ 2rot 2dup var obj! ( val env var )
+ 2swap ( val var env )
+ get-vals nil? if
+ except-message: ." tried to set unbound variable '" var obj@ print ." '."
+ recoverable-exception throw
else
- recoverable-exception throw" Tried to set unbound variable."
+ ( val vals )
+ set-car!
then
;
-
-objvar env
+hide var
: define-var ( var val env -- )
- env obj!
+ first-frame ( var val frame )
+ 2rot 2swap 2over 2over ( val var frame var frame )
- 2over env obj@ ( var val var env )
- get-vars-vals if
- 2swap 2drop ( var val vals )
- set-car!
+ get-vals-frame nil? if
2drop
- else
- env obj@
- first-frame ( var val frame )
+ -2rot 2swap 2rot
add-binding
+ else
+ ( val var frame vals )
+ 2swap 2drop 2swap 2drop
+ set-car!
then
;
-hide env
-
: make-procedure ( params body env -- proc )
nil
cons cons cons
\ }}}
+\ ---- Continuations ---- {{{
+
+: cons-return-stack ( -- listobj )
+ rsp@ 1- rsp0 = if
+ nil exit
+ then
+
+ nil rsp@ 1- rsp0 do
+ i 1+ @ fixnum-type 2swap cons
+ loop
+
+ rsp@ 1- rsp0 - fixnum-type 2swap cons
+;
+
+: cons-param-stack ( -- listobj )
+ nil
+
+ depth 2- object-stack-base @ = if
+ exit
+ then
+
+ depth 2- object-stack-base @ do
+ PSP0 i + 1 + @
+ PSP0 i + 2 + @
+
+ 2swap cons
+ 2 +loop
+
+ depth 2- 2/ fixnum-type 2swap cons
+;
+
+: make-continuation ( -- continuation true-obj )
+ \ true-obj allows calling code to detect whether
+ \ it is being called immediately following make-continuation
+ \ or by a restore-continuation.
+
+ cons-param-stack
+ cons-return-stack
+ cons drop continuation-type
+
+ true boolean-type
+;
+
+: continuation->pstack-list
+ drop pair-type car ;
+
+: continuation->rstack-list
+ drop pair-type cdr ;
+
+: stack-list-len ( stack-list -- n )
+ car drop
+;
+
+: restore-param-stack ( continuation -- obj_stack )
+ continuation->pstack-list
+ 2dup >R >R
+
+ ( Allocate stack space first using psp!,
+ then copy objects from list. )
+
+ car drop 2*
+ object-stack-base @ psp0 + + psp!
+
+ R> R> 2dup cdr
+ 2swap
+ stack-list-len 1- 0 swap do
+
+ 2dup car
+ PSP0 object-stack-base @ + i 2* + 2 + !
+ PSP0 object-stack-base @ + i 2* + 1 + !
+ cdr
+
+ -1 +loop
+
+ 2drop
+;
+
+: restore-return-stack ( continuation -- )
+
+ continuation->rstack-list
+
+ 2dup cdr 2swap stack-list-len ( list n )
+
+ dup RSP0 + RSP! \ expand return stack to accommodate entries
+
+ ( list n )
+
+ 1- \ initial offset n-1
+ 0 \ final offset 0
+ swap
+ do
+ 2dup cdr 2swap car drop
+ RSP0 i 1+ + !
+ -1 +loop
+
+ 2drop
+;
+
+: restore-continuation-with-arg ( continuation obj -- )
+
+ >R >R \ Store obj on return stack
+
+ 2dup >R >R \ Store copy of continuation on return stack
+
+ restore-param-stack
+
+ R> R> \ Pop continuation from return stack
+
+ R> R> \ Pop obj from return stack
+
+ 2swap
+
+ false boolean-type \ Add flag signifying continuation restore
+
+ 2swap
+
+ restore-return-stack
+;
+
+\ }}}
+
\ ---- Primitives ---- {{{
: make-primitive ( cfa -- )
: ensure-arg-count ( args n -- )
dup 0= if
drop nil objeq? false = if
- recoverable-exception throw" Too many arguments for primitive procedure."
+ except-message: ." Too many arguments for primitive procedure." recoverable-exception throw
then
else
-rot nil? if
- recoverable-exception throw" Too few arguments for primitive procedure."
+ except-message: ." Too few arguments for primitive procedure." recoverable-exception throw
then
cdr rot 1- recurse
: ensure-arg-type-and-count ( tn tn-1 ... t2 t1 args n -- )
dup 0= if
drop nil objeq? false = if
- recoverable-exception throw" Too many arguments for primitive procedure."
+ except-message: ." Too many arguments for primitive procedure." recoverable-exception throw
then
else
-rot nil? if
- recoverable-exception throw" Too few arguments for primitive procedure."
+ except-message: ." Too few arguments for primitive procedure." recoverable-exception throw
then
2dup cdr 2swap car ( ... t1 n args' arg1 )
2rot 1- swap 2swap rot ( ... args' n-1 arg1 t1 )
istype? false = if
- recoverable-exception throw" Incorrect type for primitive procedure."
+ except-message: ." Incorrect type for primitive procedure." recoverable-exception throw
then
2drop recurse
: ensure-arg-type ( arg type -- arg )
istype? false = if
- recoverable-exception throw" Incorrect argument type for primitive procedure."
+ except-message: ." Incorrect argument type for primitive procedure." recoverable-exception throw
then
;
( Look up macro in macro table. Returns nil if
no macro is found. )
: lookup-macro ( name_symbol -- proc )
+
+ symbol-type istype? invert if
+ \ Early exit if argument is not a symbol
+ 2drop nil exit
+ then
+
macro-table obj@
begin
parse-str 160 expect cr
span @ parse-str-span !
else
- parse-str 160 current-input-port obj@ fileport>fid read-line
+ parse-str 160 current-input-port obj@ fileport>fid orig-read-line
drop swap parse-str-span !
parse-str-span @ 0= and if append-eof then
pop-parse-idx
;
+: ratnum? ( -- bool )
+ push-parse-idx
+
+ minus? plus? or if
+ inc-parse-idx
+ then
+
+ digit? invert if
+ pop-parse-idx false exit
+ else
+ inc-parse-idx
+ then
+
+ begin digit? while
+ inc-parse-idx
+ repeat
+
+ [char] / nextchar <> if
+ pop-parse-idx false exit
+ else
+ inc-parse-idx
+ then
+
+ digit? invert if
+ pop-parse-idx false exit
+ else
+ inc-parse-idx
+ then
+
+ begin digit? while
+ inc-parse-idx
+ repeat
+
+ delim? pop-parse-idx
+;
+
: boolean? ( -- bool )
nextchar [char] # <> if false exit then
flonum-type
;
+: make-rational ( fixnum fixnum -- ratnum|fixnum )
+ drop swap drop
+ simplify
+
+ dup 1 = if
+ drop fixnum-type
+ else
+ fixnum-type swap fixnum-type
+ cons drop ratnum-type
+ then
+;
+
+: readratnum ( -- ratnum )
+ readfixnum inc-parse-idx readfixnum
+ make-rational
+;
+
: readbool ( -- bool-obj )
inc-parse-idx
;
: readstring ( -- charlist )
- nextchar [char] " = if
- inc-parse-idx
- delim? false = if
- bold fg red
- ." No delimiter following right double quote. Aborting." cr
- reset-term abort
+ nil nil
+
+ begin
+ nextchar [char] " <>
+ while
+ nextchar [char] \ = if
+ inc-parse-idx
+ nextchar case
+ [char] n of '\n' endof
+ [char] " of [char] " endof
+ [char] \
+ endcase
+ else
+ nextchar
then
+ inc-parse-idx character-type
+ nil cons
- dec-parse-idx
+ ( firstchar prevchar thischar )
- 0 nil-type exit
- then
+ 2swap nil? if
+ 2drop 2swap 2drop 2dup ( thischar thischar )
+ else
+ ( firstchar thischar prevchar )
+ 2over 2swap set-cdr! ( firstchar thischar )
+ then
+ repeat
- nextchar [char] \ = if
- inc-parse-idx
- nextchar case
- [char] n of '\n' endof
- [char] " of [char] " endof
- [char] \
- endcase
- else
- nextchar
+ \ Discard previous character
+ 2drop
+
+ inc-parse-idx
+ delim? false = if
+ bold fg red
+ ." No delimiter following right double quote. Aborting." cr
+ reset-term abort
then
- inc-parse-idx character-type
- recurse
+ dec-parse-idx
- cons
+ nil? if
+ nil cons
+ then
+ drop string-type
;
: readsymbol ( -- charlist )
exit
then
+ ratnum? if
+ readratnum
+ exit
+ then
+
boolean? if
readbool
exit
inc-parse-idx
readstring
- drop string-type
nextchar [char] " <> if
bold red ." Missing closing double-quote." reset-term cr
exit
then
+ nextchar [char] ) = if
+ inc-parse-idx
+ except-message: ." unmatched closing parenthesis." recoverable-exception throw
+ then
+
\ Anything else is parsed as a symbol
readsymbol charlist>symbol
\ }}}
-\ ---- Eval ---- {{{
+\ ---- Syntax ---- {{{
: self-evaluating? ( obj -- obj bool )
boolean-type istype? if true exit then
fixnum-type istype? if true exit then
flonum-type istype? if true exit then
+ ratnum-type istype? if true exit then
character-type istype? if true exit then
string-type istype? if true exit then
nil-type istype? if true exit then
: quote-body ( quote-obj -- quote-body-obj )
cdr car ;
-: quasiquote? ( obj -- obj bool )
- quasiquote-symbol tagged-list? ;
-
-: unquote? ( obj -- obj bool )
- unquote-symbol tagged-list? ;
-
-: unquote-splicing? ( obj -- obj bool )
- unquote-splicing-symbol tagged-list? ;
-
-: eval-unquote ( env obj -- res )
- cdr ( env args )
-
- nil? if
- recoverable-exception throw" no arguments to unquote."
- then
-
- 2dup cdr
- nil? false = if
- recoverable-exception throw" too many arguments to unquote."
- then
-
- 2drop car 2swap eval
-;
-
-( Create a new list from elements of l1 consed on to l2 )
-: join-lists ( l2 l1 -- l3 )
- nil? if 2drop exit then
-
- 2dup car
- -2rot cdr
- recurse cons
-;
-
-defer eval-quasiquote-item
-: eval-quasiquote-pair ( env obj -- res )
- 2over 2over ( env obj env obj )
-
- cdr eval-quasiquote-item
-
- -2rot car ( cdritem env objcar )
-
- unquote-splicing? if
- eval-unquote ( cdritems caritem )
-
- 2swap nil? if
- 2drop
- else
- 2swap join-lists
- then
- else
- eval-quasiquote-item ( cdritems caritem )
- 2swap cons
- then
-
-;
-
-:noname ( env obj )
- nil? if
- 2swap 2drop exit
- then
-
- unquote? if
- eval-unquote exit
- then
-
- pair-type istype? if
- eval-quasiquote-pair exit
- then
-
- 2swap 2drop
-; is eval-quasiquote-item
-
-: eval-quasiquote ( obj env -- res )
- 2swap cdr ( env args )
-
- nil? if
- recoverable-exception throw" no arguments to quasiquote."
- then
-
- 2dup cdr ( env args args-cdr )
- nil? false = if
- recoverable-exception throw" too many arguments to quasiquote."
- then
-
- 2drop car ( env arg )
-
- eval-quasiquote-item
-;
-
: variable? ( obj -- obj bool )
symbol-type istype? ;
: definition? ( obj -- obj bool )
define-symbol tagged-list? ;
-: make-lambda ( params body -- lambda-exp )
- lambda-symbol -2rot cons cons ;
-
-( Handles iterative expansion of defines in
- terms of nested lambdas. Most Schemes only
- handle one iteration of expansion! )
-: definition-var-val ( obj -- var val )
-
- cdr 2dup cdr 2swap car ( val var )
-
- begin
- symbol-type istype? false =
- while
- 2dup cdr 2swap car ( val formals var' )
- -2rot 2swap ( var' formals val )
- make-lambda nil cons ( var' val' )
- 2swap ( val' var' )
- repeat
-
- 2swap car
-;
-
-: eval-definition ( obj env -- res )
- 2dup 2rot ( env env obj )
- definition-var-val ( env env var val )
- 2rot eval ( env var val )
-
- 2rot ( var val env )
- define-var
+: definition-var ( obj -- var )
+ cdr car ;
- ok-symbol
-;
+: definition-val ( obj -- val )
+ cdr cdr car ;
: assignment? ( obj -- obj bool )
set!-symbol tagged-list? ;
: assignment-val ( obj -- val )
cdr cdr car ;
-: eval-assignment ( obj env -- res )
- 2swap
- 2over 2over ( env obj env obj )
- assignment-val 2swap ( env obj valexp env )
- eval ( env obj val )
-
- 2swap assignment-var 2swap ( env var val )
-
- 2rot ( var val env )
- set-var
-
- ok-symbol
-;
-
: macro-definition? ( obj -- obj bool )
define-macro-symbol tagged-list? ;
: macro-definition-body ( exp -- body )
cdr cdr ;
-objvar env
-: eval-define-macro ( obj env -- res )
- env obj!
-
- 2dup macro-definition-name 2swap ( name obj )
- 2dup macro-definition-params 2swap ( name params obj )
- macro-definition-body ( name params body )
-
- env obj@ ( name params body env )
-
- make-macro
-
- ok-symbol
-;
-hide env
-
: if? ( obj -- obj bool )
if-symbol tagged-list? ;
: lambda-body ( obj -- body )
cdr cdr ;
-: begin? ( obj -- obj bool )
- begin-symbol tagged-list? ;
-
-: begin-actions ( obj -- actions )
- cdr ;
-
-: eval-sequence ( explist env -- finalexp env )
- ( Evaluates all bar the final expressions in
- an an expression list. The final expression
- is returned to allow for tail optimization. )
-
- 2swap ( env explist )
-
- \ Abort on empty list
- nil? if
- 2drop none
- 2swap exit
- then
-
- begin
- 2dup cdr ( env explist nextexplist )
- nil? false =
- while
- -2rot car 2over ( nextexplist env exp env )
- eval
- 2drop \ discard result
- 2swap ( env nextexplist )
- repeat
-
- 2drop car 2swap ( finalexp env )
-;
-
: application? ( obj -- obj bool )
pair-type istype? ;
: rest-operands ( operands -- other-operands )
cdr ;
-: list-of-vals ( args env -- vals )
- 2swap
-
- 2dup nooperands? if
- 2swap 2drop
- else
- 2over 2over first-operand 2swap eval
- -2rot rest-operands 2swap recurse
- cons
- then
-;
-
: procedure-params ( proc -- params )
drop pair-type car ;
: flatten-proc-args ( argvals argnames -- argvals' argnames' )
nil? if
2over nil? false = if
- recoverable-exception throw" Too many arguments for compound procedure."
+ except-message: ." Too many arguments for compound procedure." recoverable-exception throw
else
2drop
then
2over
nil? if
- recoverable-exception throw" Too few arguments for compound procedure."
+ except-message: ." Too few arguments for compound procedure." recoverable-exception throw
else
cdr
then
2swap
;
-: apply ( proc argvals -- result )
- 2swap dup case
- primitive-proc-type of
- drop execute
- endof
+\ }}}
+
+\ ---- Analyze ---- {{{
+
+: evaluate-eproc ( eproc env --- res )
+
+ >R >R
+
+ begin
+ nil? invert
+ while
+ 2dup car
+ 2swap cdr
+ repeat
+
+ 2drop \ get rid of null
+
+ R> R> 2swap
+
+ \ Final element of eproc list is primitive procedure
+ drop \ dump type signifier
+
+ goto \ jump straight to primitive procedure (executor)
+;
+
+: self-evaluating-executor ( exp env -- exp )
+ 2drop ;
+
+: analyze-self-evaluating ( exp --- eproc )
+ ['] self-evaluating-executor primitive-proc-type
+ nil cons cons
+;
+
+: quote-executor ( exp env -- exp )
+ 2drop ;
+
+: analyze-quoted ( exp -- eproc )
+ quote-body
+
+ ['] quote-executor primitive-proc-type
+ nil cons cons
+;
+
+: variable-executor ( var env -- val )
+ lookup-var ;
+
+: analyze-variable ( exp -- eproc )
+ ['] variable-executor primitive-proc-type
+ nil cons cons
+;
+
+: definition-executor ( var val-eproc env -- ok )
+ 2swap 2over ( var env val-eproc env )
+ evaluate-eproc 2swap ( var val env )
+ define-var
+ ok-symbol
+;
+
+: analyze-definition ( exp -- eproc )
+ 2dup definition-var
+ 2swap definition-val analyze
+
+ ['] definition-executor primitive-proc-type
+ nil cons cons cons
+;
+
+: assignment-executor ( var val-eproc env -- ok )
+ 2swap 2over ( var env val-eproc env )
+ evaluate-eproc 2swap ( var val env )
+ set-var
+ ok-symbol
+;
+
+: analyze-assignment ( exp -- eproc )
+ 2dup assignment-var
+ 2swap assignment-val analyze ( var val-eproc )
+
+ ['] assignment-executor primitive-proc-type
+ nil cons cons cons
+;
+
+: sequence-executor ( eproc-list env -- res )
+ 2swap
+
+ begin
+ 2dup cdr ( env elist elist-rest)
+ nil? invert
+ while
+ -2rot car 2over ( elist-rest env elist-head env )
+ evaluate-eproc ( elist-rest env head-res )
+ 2drop 2swap ( env elist-rest )
+ repeat
+
+ 2drop car 2swap
+ ['] evaluate-eproc goto
+;
+
+
+: (analyze-sequence) ( explist -- eproc-list )
+ nil? if exit then
+
+ 2dup car analyze
+ 2swap cdr recurse
+
+ cons
+;
+
+: analyze-sequence ( explist -- eproc )
+ (analyze-sequence)
+ ['] sequence-executor primitive-proc-type
+ nil cons cons
+;
+
+
+: macro-definition-executor ( name params bproc env -- ok )
+ make-macro ok-symbol
+;
+
+: analyze-macro-definition ( exp -- eproc )
+ 2dup macro-definition-name
+ 2swap 2dup macro-definition-params
+ 2swap macro-definition-body analyze-sequence
+
+ ['] macro-definition-executor primitive-proc-type
+ nil cons cons cons cons
+;
+
+: if-executor ( cproc aproc pproc env -- res )
+ 2swap 2over ( cproc aproc env pproc env -- res )
+ evaluate-eproc
+
+ true? if
+ 2swap 2drop
+ else
+ 2rot 2drop
+ then
+
+ ['] evaluate-eproc goto
+;
+
+: analyze-if ( exp -- eproc )
+ 2dup if-consequent analyze
+ 2swap 2dup if-alternative analyze
+ 2swap if-predicate analyze
+
+ ['] if-executor primitive-proc-type
+ nil cons cons cons cons
+;
+
+: lambda-executor ( params bproc env -- res )
+ make-procedure
+ ( Although this is packaged up as a regular compound procedure,
+ the "body" element contains an _eproc_ to be evaluated in an
+ environment resulting from extending env with the parameter
+ bindings. )
+;
+
+: analyze-lambda ( exp -- eproc )
+ 2dup lambda-parameters
+ 2swap lambda-body
+
+ nil? if
+ except-message: ." encountered lambda with an empty body." recoverable-exception throw
+ then
+
+ analyze-sequence
+
+ ['] lambda-executor primitive-proc-type
+ nil cons cons cons
+;
+
+: operand-eproc-list ( operands -- eprocs )
+ nil? invert if
+ 2dup car analyze
+ 2swap cdr recurse
+ cons
+ then
+;
- compound-proc-type of
- 2dup procedure-body ( argvals proc body )
- -2rot 2dup procedure-params ( body argvals proc argnames )
- -2rot procedure-env ( body argnames argvals procenv )
+: evaluate-operand-eprocs ( env aprocs -- vals )
+ nil? if
+ 2swap 2drop
+ else
+ 2over 2over car 2swap evaluate-eproc ( env aprocs thisval )
+ -2rot cdr recurse ( thisval restvals )
+ cons
+ then
+;
+
+: apply ( vals proc )
+ dup case
+ primitive-proc-type of
+ drop execute
+ endof
+
+ compound-proc-type of
+ 2dup procedure-body ( argvals proc bproc )
+ -2rot 2dup procedure-params ( bproc argvals proc argnames )
+ -2rot procedure-env ( bproc argnames argvals procenv )
-2rot 2swap
flatten-proc-args
2swap 2rot
- extend-env ( body env )
+ extend-env ( bproc env )
+
+ ['] evaluate-eproc goto
+ endof
+
+ continuation-type of
+ 2swap
+ nil? if
+ except-message: ." Continuations expect exactly 1 argument."
+ recoverable-exception throw
+ then
- eval-sequence
+ 2dup cdr
- R> drop ['] eval goto-deferred \ Tail call optimization
- endof
+ nil? invert if
+ except-message: ." Continuations expect exactly 1 argument."
+ recoverable-exception throw
+ then
- recoverable-exception throw" Object not applicable."
- endcase
+ 2drop car
+
+ restore-continuation-with-arg
+ endof
+
+ except-message: ." object '" drop print ." ' not applicable." recoverable-exception throw
+ endcase
;
+: application-executor ( operator-proc arg-procs env -- res )
+ 2rot 2over ( aprocs env fproc env )
+ evaluate-eproc ( aprocs env proc )
+
+ -2rot 2swap ( proc env aprocs )
+ evaluate-operand-eprocs ( proc vals )
+
+ 2swap ( vals proc )
+
+ ['] apply goto
+;
+
+: analyze-application ( exp -- eproc )
+ 2dup operator analyze
+ 2swap operands operand-eproc-list
+
+ ['] application-executor primitive-proc-type
+ nil cons cons cons
+;
+
+:noname ( exp --- eproc )
+
+ self-evaluating? if analyze-self-evaluating exit then
+
+ quote? if analyze-quoted exit then
+
+ variable? if analyze-variable exit then
+
+ definition? if analyze-definition exit then
+
+ assignment? if analyze-assignment exit then
+
+ macro-definition? if analyze-macro-definition exit then
+
+ if? if analyze-if exit then
+
+ lambda? if analyze-lambda exit then
+
+ application? if analyze-application exit then
+
+ except-message: ." tried to analyze unknown expression type." recoverable-exception throw
+
+; is analyze
+
+\ }}}
+
+\ ---- Macro Expansion ---- {{{
+
( Simply evaluates the given procedure with expbody as its argument. )
-: macro-expand ( proc expbody -- result )
+: macro-eval ( proc expbody -- result )
2swap
- 2dup procedure-body ( expbody proc procbody )
- -2rot 2dup procedure-params ( procbody expbody proc argnames )
- -2rot procedure-env ( procbody argnames expbody procenv )
+ 2dup procedure-body ( expbody proc bproc )
+ -2rot 2dup procedure-params ( bproc expbody proc argnames )
+ -2rot procedure-env ( bproc argnames expbody procenv )
-2rot 2swap
flatten-proc-args
2swap 2rot
- extend-env eval-sequence eval
+ extend-env ( bproc env )
+
+ ['] evaluate-eproc goto
;
-:noname ( obj env -- result )
- 2swap
+: expand-macro ( exp -- result )
+ pair-type istype? invert if exit then
- self-evaluating? if
- 2swap 2drop
- exit
- then
+ 2dup car symbol-type istype? invert if 2drop exit then
- quote? if
- quote-body
+ lookup-macro nil? if 2drop exit then
+
+ 2over cdr macro-eval
+
+ 2dup no-match-symbol objeq? if
+ 2drop exit
+ else
2swap 2drop
- exit
then
- quasiquote? if
- 2swap eval-quasiquote
- exit
- then
+ R> drop ['] expand goto-deferred
+;
- variable? if
- 2swap lookup-var
- exit
- then
+: expand-definition ( exp -- result )
+ define-symbol 2swap
- definition? if
- 2swap eval-definition
- exit
- then
+ 2dup definition-var
+ 2swap definition-val expand
+ nil ( define var val' nil )
- assignment? if
- 2swap eval-assignment
- exit
- then
+ cons cons cons ;
- macro-definition? if
- 2swap eval-define-macro
- exit
- then
+: expand-assignment ( exp -- result )
+ set!-symbol 2swap
- if? if
- 2over 2over
- if-predicate
- 2swap eval
+ 2dup assignment-var
+ 2swap assignment-val expand
+ nil ( define var val' nil )
- true? if
- if-consequent
- else
- if-alternative
- then
+ cons cons cons ;
- 2swap
- ['] eval goto-deferred
- then
+: expand-list ( exp -- res )
+ nil? if exit then
- lambda? if
- 2dup lambda-parameters
- 2swap lambda-body
- 2rot make-procedure
- exit
- then
+ 2dup car expand
+ 2swap cdr recurse
+
+ cons ;
+
+: macro-definition-nameparams
+ cdr car ;
+
+: expand-define-macro ( exp -- res )
+ define-macro-symbol 2swap
+ 2dup macro-definition-nameparams
+ 2swap macro-definition-body expand-list
+
+ cons cons ;
- begin? if
- begin-actions 2swap
- eval-sequence
- ['] eval goto-deferred
+: expand-lambda ( exp -- res )
+ lambda-symbol 2swap
+ 2dup lambda-parameters
+ 2swap lambda-body expand-list
+
+ cons cons ;
+
+: expand-if ( exp -- res )
+ if-symbol 2swap
+
+ 2dup if-predicate expand
+ 2swap 2dup if-consequent expand
+ 2swap if-alternative none? if
+ 2drop nil
+ else
+ expand nil cons
then
- application? if
+ cons cons cons ;
- 2over 2over ( env exp env exp )
- operator ( env exp env opname )
+: expand-application ( exp -- res )
+ 2dup operator expand
+ 2swap operands expand-list
- 2dup lookup-macro nil? false = if
- \ Macro function evaluation
+ cons ;
- ( env exp env opname mproc )
- 2swap 2drop -2rot 2drop cdr ( env mproc body )
+:noname ( exp -- result )
+ expand-macro
- macro-expand
+ self-evaluating? if exit then
- 2swap
- ['] eval goto-deferred
- else
- \ Regular function application
+ quote? if exit then
- 2drop ( env exp env opname )
+ definition? if expand-definition exit then
- 2swap eval ( env exp proc )
+ assignment? if expand-assignment exit then
- -2rot ( proc env exp )
- operands 2swap ( proc operands env )
- list-of-vals ( proc argvals )
+ macro-definition? if expand-define-macro exit then
- apply
- exit
- then
- then
+ lambda? if expand-lambda exit then
- recoverable-exception throw" Tried to evaluate object with unknown type."
-; is eval
+ if? if expand-if exit then
+
+ application? if expand-application exit then
+
+; is expand
\ }}}
+:noname ( exp env -- res )
+ 2swap expand analyze 2swap evaluate-eproc
+; is eval
+
\ ---- Print ---- {{{
: printfixnum ( fixnum -- ) drop 0 .R ;
: printflonum ( flonum -- ) drop f. ;
+: printratnum ( ratnum -- )
+ drop pair-type 2dup
+ car print ." /" cdr print
+;
+
: printbool ( bool -- )
drop if
." #t"
: printcomp ( primobj -- )
2drop ." <compound procedure>" ;
+: printcont ( primobj --)
+ 2drop ." <continuation>" ;
+
: printnone ( noneobj -- )
2drop ." Unspecified return value" ;
:noname ( obj -- )
fixnum-type istype? if printfixnum exit then
flonum-type istype? if printflonum exit then
+ ratnum-type istype? if printratnum exit then
boolean-type istype? if printbool exit then
character-type istype? if printchar exit then
string-type istype? if printstring exit then
pair-type istype? if ." (" printpair ." )" exit then
primitive-proc-type istype? if printprim exit then
compound-proc-type istype? if printcomp exit then
+ continuation-type istype? if printcont exit then
none-type istype? if printnone exit then
+ port-type istype? if printport exit then
- recoverable-exception throw" Tried to print object with unknown type."
+ except-message: ." tried to print object with unknown type." recoverable-exception throw
; is print
\ }}}
\ ---- Garbage Collection ---- {{{
-variable gc-enabled
-false gc-enabled !
-
-variable gc-stack-depth
+( Notes on garbage collection:
+ This is a mark-sweep garbage collector, invoked by cons.
+ The roots of the object tree used by the marking routine
+ include all objects in the parameter stack, and several
+ other fixed roots such as global-env, symbol-table, macro-table,
+ and the console-i/o-port.
-: enable-gc
- depth gc-stack-depth !
- true gc-enabled ! ;
+ NO OTHER OBJECTS WILL BE MARKED!
-: disable-gc
- false gc-enabled ! ;
+ This places implicit restrictions on when cons can be invoked.
+ Invoking cons when live objects are stored on the return stack
+ or in other variables than the above will result in possible
+ memory corruption if the cons triggers the GC. )
-: gc-enabled?
- gc-enabled @ ;
: pairlike? ( obj -- obj bool )
pair-type istype? if true exit then
string-type istype? if true exit then
symbol-type istype? if true exit then
compound-proc-type istype? if true exit then
+ port-type istype? if true exit then
+ continuation-type istype? if true exit then
false
;
symbol-table obj@ gc-mark-obj
macro-table obj@ gc-mark-obj
+ console-i/o-port obj@ gc-mark-obj
global-env obj@ gc-mark-obj
- depth gc-stack-depth @ do
+ depth object-stack-base @ do
PSP0 i + 1 + @
PSP0 i + 2 + @
\ ---- Loading files ---- {{{
-: charlist>cstr ( charlist addr -- n )
-
- dup 2swap ( origaddr addr charlist )
-
- begin
- nil? false =
- while
- 2dup cdr 2swap car
- drop ( origaddr addr charlist char )
- -rot 2swap ( origaddr charlist addr char )
- over !
- 1+ -rot ( origaddr nextaddr charlist )
- repeat
-
- 2drop ( origaddr finaladdr )
- swap -
-;
-
: load ( addr n -- finalResult )
open-input-file
ok-symbol ( port res )
begin
+ \ DEBUG
+ \ bold fg blue ." READ from " 2over drop . ." ==> " reset-term
+
2over read-port ( port res obj )
+ \ DEBUG
+ \ 2dup print cr
+
2dup EOF character-type objeq? if
2drop 2swap close-port
exit
include scheme-primitives.4th
+ init-object-stack-base
s" scheme-library.scm" load 2drop
\ }}}
;
: repl
- cr ." Welcome to scheme.forth.jl!" cr
- ." Use Ctrl-D to exit." cr
-
empty-parse-str
- enable-gc
+ init-object-stack-base
+
+ \ Display welcome message
+ welcome-symbol nil cons global-env obj@ eval 2drop
begin
['] repl-body catch
The Lambda Lab / projects / scheme.forth.jl.git / blobdiff