include term-colours.4th
include defer-is.4th
-include throw-catch.4th
include float.4th
+include debugging.4th
+
defer read
defer eval
defer print
+defer collect-garbage
+
\ ------ Types ------
variable nexttype
0 nexttype !
: make-type
create nexttype @ ,
- nexttype @ 1+ nexttype !
+ 1 nexttype +!
does> @ ;
make-type fixnum-type
make-type character-type
make-type string-type
make-type nil-type
+make-type none-type
make-type pair-type
make-type symbol-type
make-type primitive-proc-type
make-type compound-proc-type
+make-type fileport-type
: istype? ( obj type -- obj bool )
over = ;
-\ ------ Cons cell memory ------ {{{
+\ ---- List-structured memory ---- {{{
+
+10000 constant scheme-memsize
-10000 constant N
-create car-cells N allot
-create car-type-cells N allot
-create cdr-cells N allot
-create cdr-type-cells N allot
+create car-cells scheme-memsize allot
+create car-type-cells scheme-memsize allot
+create cdr-cells scheme-memsize allot
+create cdr-type-cells scheme-memsize allot
+create nextfrees scheme-memsize allot
+:noname
+ scheme-memsize 0 do
+ i 1+ nextfrees i + !
+ loop
+; execute
+
variable nextfree
0 nextfree !
+: inc-nextfree
+ nextfrees nextfree @ + @
+ nextfree !
+
+ nextfree @ scheme-memsize >= if
+ collect-garbage
+ then
+
+ nextfree @ scheme-memsize >= if
+ fg red bold
+ ." Out of memory! Aborting."
+ reset-term abort
+ then
+;
+
: cons ( car-obj cdr-obj -- pair-obj )
cdr-type-cells nextfree @ + !
cdr-cells nextfree @ + !
car-cells nextfree @ + !
nextfree @ pair-type
-
- 1 nextfree +!
+ inc-nextfree
;
: car ( pair-obj -- car-obj )
: nil 0 nil-type ;
: nil? nil-type istype? ;
+: none 0 none-type ;
+: none? none-type istype? ;
+
: objvar create nil swap , , ;
: value@ ( objvar -- val ) @ ;
\ }}}
+\ ---- 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 ;
+
+\ }}}
+
\ ---- Pre-defined symbols ---- {{{
objvar symbol-table
: duplicate-charlist ( charlist -- copy )
- 2dup nil objeq? false = if
+ nil? false = if
2dup car 2swap cdr recurse cons
then ;
;
-: (create-symbol) ( addr n -- symbol-obj )
+: cstr>charlist ( addr n -- symbol-obj )
dup 0= if
2drop nil
else
bl word
count
- (create-symbol)
+ cstr>charlist
drop symbol-type
2dup
does> dup @ swap 1+ @
;
-create-symbol quote quote-symbol
-create-symbol define define-symbol
-create-symbol set! set!-symbol
-create-symbol ok ok-symbol
-create-symbol if if-symbol
-create-symbol lambda lambda-symbol
-create-symbol λ λ-symbol
+create-symbol quote quote-symbol
+create-symbol define define-symbol
+create-symbol define-macro define-macro-symbol
+create-symbol set! set!-symbol
+create-symbol ok ok-symbol
+create-symbol if if-symbol
+create-symbol lambda lambda-symbol
+create-symbol λ λ-symbol
+create-symbol begin begin-symbol
\ }}}
: get-vars-vals ( var env -- vars? vals? bool )
begin
- 2dup nil objeq? false =
+ nil? false =
while
2over 2over first-frame
get-vars-vals-frame if
hide env
+: make-procedure ( params body env -- proc )
+ nil
+ cons cons cons
+ drop compound-proc-type
+;
+
objvar global-env
nil nil nil extend-env
global-env obj!
\ }}}
-\ ---- Primitives ---- {{{
+\ ---- Macros ---- {{{
-: make-primitive ( cfa -- )
- bl word
- count
+objvar macro-table
- (create-symbol)
- drop symbol-type
-
- 2dup
+( Look up macro in macro table. Returns nil if
+ no macro is found. )
+: lookup-macro ( name_symbol -- proc )
+ macro-table obj@
- symbol-table obj@
- cons
- symbol-table obj!
+ begin
+ nil? false =
+ while
+ 2over 2over
+ car car objeq? if
+ 2swap 2drop
+ car cdr
+ exit
+ then
- rot primitive-proc-type ( var prim )
- global-env obj@ define-var
-;
+ cdr
+ repeat
-: arg-count-error
- bold fg red ." Incorrect argument count." reset-term cr
- abort
+ 2swap 2drop
;
-: ensure-arg-count ( args n -- )
- dup 0= if
- drop nil objeq? false = if
- arg-count-error
- then
- else
- -rot 2dup nil objeq? if
- arg-count-error
+: make-macro ( name_symbol params body env -- )
+ make-procedure
+
+ 2swap ( proc name_symbol )
+
+ macro-table obj@
+
+ begin
+ nil? false =
+ while
+ 2over 2over ( proc name table name table )
+ car car objeq? if
+ 2swap 2drop ( proc table )
+ car ( proc entry )
+ set-cdr!
+ exit
then
-
- cdr rot 1- recurse
- then
-;
-: arg-type-error
- bold fg red ." Incorrect argument type." reset-term cr
- abort
-;
+ cdr
+ repeat
-: ensure-arg-type ( arg type -- arg )
- istype? false = if
- arg-type-error
- then
-;
+ 2drop
-include scheme-primitives.4th
+ 2swap cons
+ macro-table obj@ cons
+ macro-table obj!
+;
\ }}}
'\n' parse-str parse-str-span @ + !
1 parse-str-span +! ;
+: append-eof
+ 4 parse-str parse-str-span @ + !
+ 1 parse-str-span +! ;
+
: empty-parse-str
0 parse-str-span !
0 parse-idx ! ;
: getline
- parse-str 160 expect cr
- span @ parse-str-span !
+ current-input-port obj@ console-i/o-port obj@ objeq? if
+ parse-str 160 expect cr
+ span @ parse-str-span !
+ else
+ parse-str 160 current-input-port obj@ fileport>fid read-line
+ drop swap parse-str-span !
+
+ parse-str-span @ 0= and if append-eof then
+ then
append-newline
0 parse-idx ! ;
charavailable? false = if getline then
parse-str parse-idx @ + @ ;
+: '\t' 9 ;
: whitespace? ( -- bool )
nextchar BL =
- nextchar '\n' = or ;
+ nextchar '\n' =
+ nextchar '\t' =
+ or or ;
+: EOF 4 ;
: eof? ( -- bool )
- nextchar 4 = ;
+ nextchar EOF = ;
: delim? ( -- bool )
whitespace?
realnum-type
;
-: readbool ( -- bool-atom )
+: readbool ( -- bool-obj )
inc-parse-idx
nextchar [char] f = if
boolean-type
;
-: readchar ( -- char-atom )
+: readchar ( -- char-obj )
inc-parse-idx
inc-parse-idx
then
eof? if
+ EOF character-type
inc-parse-idx
- bold fg blue ." Moriturus te saluto." reset-term ." ok" cr
- quit
+ exit
then
\ Anything else is parsed as a symbol
character-type istype? if true exit then
string-type istype? if true exit then
nil-type istype? if true exit then
+ none-type istype? if true exit then
false
;
ok-symbol
;
+: macro-definition? ( obj -- obj bool )
+ define-macro-symbol tagged-list? ;
+
+: macro-definition-name ( exp -- mname )
+ cdr car car ;
+
+: macro-definition-params ( exp -- params )
+ cdr car cdr ;
+
+: 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? ;
: if-alternative ( ifobj -- alt|false )
cdr cdr cdr
- 2dup nil objeq? if
+ nil? if
2drop false
else
car
: lambda-body ( obj -- body )
cdr cdr ;
-: make-procedure ( params body env -- proc )
- nil
- cons cons cons
- drop compound-proc-type
+: 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)
+: application? ( obj -- obj bool )
pair-type istype? ;
: operator ( obj -- operator )
: procedure-env ( proc -- body )
drop pair-type cdr cdr car ;
-: apply ( proc args )
+( Ensure terminating symbol arg name is handled
+ specially to allow for variadic procedures. )
+: flatten-proc-args ( argvals argnames -- argvals' argnames' )
+ nil? if exit then
+
+ symbol-type istype? if
+ nil cons
+ 2swap
+ nil cons
+ 2swap
+ exit
+ then
+
+ 2over cdr 2over cdr
+ recurse ( argvals argnames argvals'' argnames'' )
+ 2rot car 2swap cons ( argvals argvals'' argnames' )
+ 2rot car 2rot cons ( argnames' argvals' )
+ 2swap
+;
+
+: apply ( proc argvals -- result )
2swap dup case
primitive-proc-type of
drop execute
endof
compound-proc-type of
- 2dup procedure-body ( args proc body )
- -2rot 2dup procedure-params ( body args proc params )
- -2rot procedure-env ( body params args procenv )
-
- extend-env ( body env )
+ 2dup procedure-body ( argvals proc body )
+ -2rot 2dup procedure-params ( body argvals proc argnames )
+ -2rot procedure-env ( body argnames argvals procenv )
- 2swap ( env body )
+ -2rot 2swap
+ flatten-proc-args
+ 2swap 2rot
- begin
- 2dup cdr 2dup nil objeq? false =
- while
- -2rot car 2over ( nextbody env exp env )
- eval
- 2drop \ discard result
- 2swap ( env nextbody )
- repeat
+ extend-env ( body env )
- 2drop ( env body )
- car 2swap ( exp env )
+ eval-sequence
R> drop ['] eval goto-deferred \ Tail call optimization
endof
- bold fg red ." Object not applicable. Aboring." reset-term cr
+ bold fg red ." Object not applicable. Aborting." reset-term cr
abort
endcase
;
+: macro-expand ( 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 )
+
+ -2rot 2swap
+ flatten-proc-args
+ 2swap 2rot
+
+ extend-env eval-sequence eval
+;
+
:noname ( obj env -- result )
2swap
exit
then
+ macro-definition? if
+ 2swap eval-define-macro
+ exit
+ then
+
if? if
2over 2over
if-predicate
exit
then
+ begin? if
+ begin-actions 2swap
+ eval-sequence
+ ['] eval goto-deferred
+ then
+
application? if
- 2over 2over
- operator 2swap eval
- -2rot
- operands 2swap list-of-vals
- apply
+ 2over 2over ( env exp env exp )
+ operator 2dup ( env exp env opname opname )
+
+ lookup-macro nil? if
+ \ Regular function application
+
+ 2drop ( env exp env opname )
+
+ 2swap eval ( env exp proc )
+ -2rot ( proc env exp )
+ operands 2swap ( proc operands env )
+ list-of-vals ( proc argvals )
+
+ apply
+ else
+ \ Macro function evaluation
+
+ ( env exp env opname mproc )
+ 2swap 2drop -2rot 2drop cdr ( env mproc body )
+
+ 2dup print cr
+ macro-expand
+ 2dup print cr
+
+ 2swap
+ ['] eval goto-deferred
+ then
exit
then
: printcomp ( primobj -- )
2drop ." <compound procedure>" ;
+: printnone ( noneobj -- )
+ 2drop ." Unspecified return value" ;
+
:noname ( obj -- )
fixnum-type istype? if printfixnum exit then
realnum-type istype? if printrealnum 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
+ none-type istype? if printnone exit then
bold fg red ." Error printing expression - unrecognized type. Aborting" reset-term cr
abort
\ }}}
+\ ---- Garbage Collection ---- {{{
+
+variable gc-enabled
+false gc-enabled !
+
+variable gc-stack-depth
+
+: enable-gc
+ depth gc-stack-depth !
+ true gc-enabled ! ;
+
+: disable-gc
+ false gc-enabled ! ;
+
+: 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
+
+ false
+;
+
+: pairlike-marked? ( obj -- obj bool )
+ over nextfrees + @ 0=
+;
+
+: mark-pairlike ( obj -- obj )
+ over nextfrees + 0 swap !
+;
+
+: gc-unmark ( -- )
+ scheme-memsize 0 do
+ 1 nextfrees i + !
+ loop
+;
+
+: gc-mark-obj ( obj -- )
+
+ pairlike? invert if 2drop exit then
+ pairlike-marked? if 2drop exit then
+
+ mark-pairlike
+
+ drop pair-type 2dup
+
+ car recurse
+ cdr recurse
+;
+
+: gc-sweep
+ scheme-memsize nextfree !
+ 0 scheme-memsize 1- do
+ nextfrees i + @ 0<> if
+ nextfree @ nextfrees i + !
+ i nextfree !
+ then
+ -1 +loop
+;
+
+\ Following a GC, this gives the amount of free memory
+: gc-count-marked
+ 0
+ scheme-memsize 0 do
+ nextfrees i + @ 0= if 1+ then
+ loop
+;
+
+\ Debugging word - helps spot memory that is retained
+: gc-zero-unmarked
+ scheme-memsize 0 do
+ nextfrees i + @ 0<> if
+ 0 car-cells i + !
+ 0 cdr-cells i + !
+ then
+ loop
+;
+
+:noname
+ \ ." GC! "
+
+ gc-unmark
+
+ symbol-table obj@ gc-mark-obj
+ macro-table obj@ gc-mark-obj
+ global-env obj@ gc-mark-obj
+
+ depth gc-stack-depth @ do
+ PSP0 i + 1 + @
+ PSP0 i + 2 + @
+
+ gc-mark-obj
+ 2 +loop
+
+ gc-sweep
+
+ \ ." (" gc-count-marked . ." pairs marked as used.)" cr
+; is collect-garbage
+
+\ }}}
+
+\ ---- 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
+
+ empty-parse-str
+
+ ok-symbol ( port res )
+
+ begin
+ 2over read-port ( port res obj )
+
+ 2dup EOF character-type objeq? if
+ 2drop 2swap close-port
+ exit
+ then
+
+ 2swap 2drop ( port obj )
+
+ global-env obj@ eval ( port res )
+ again
+;
+
+\ }}}
+
+\ ---- Primitives ---- {{{
+
+: make-primitive ( cfa -- )
+ bl word
+ count
+
+ \ 2dup ." Defining primitive " type ." ..." cr
+
+ cstr>charlist
+ drop symbol-type
+
+ 2dup
+
+ symbol-table obj@
+ cons
+ symbol-table obj!
+
+ rot primitive-proc-type ( var prim )
+ global-env obj@ define-var
+;
+
+: arg-count-error
+ bold fg red ." Incorrect argument count." reset-term cr
+ abort
+;
+
+: ensure-arg-count ( args n -- )
+ dup 0= if
+ drop nil objeq? false = if
+ arg-count-error
+ then
+ else
+ -rot nil? if
+ arg-count-error
+ then
+
+ cdr rot 1- recurse
+ then
+;
+
+: arg-type-error
+ bold fg red ." Incorrect argument type." reset-term cr
+ abort
+;
+
+: ensure-arg-type ( arg type -- arg )
+ istype? false = if
+ arg-type-error
+ then
+;
+
+include scheme-primitives.4th
+
+\ }}}
+
+\ ---- Standard Library ---- {{{
+
+ s" scheme-library.scm" load 2drop
+
+\ }}}
+
\ ---- REPL ----
: repl
empty-parse-str
+ enable-gc
+
begin
cr bold fg green ." > " reset-term
- read
+ read-console
+
+ 2dup EOF character-type objeq? if
+ 2drop
+ bold fg blue ." Moriturus te saluto." reset-term cr
+ exit
+ then
+
global-env obj@ eval
+
fg cyan ." ; " print reset-term
again
;
The Lambda Lab / projects / scheme.forth.jl.git / blobdiff