include term-colours.4th
include defer-is.4th
-include throw-catch.4th
+include float.4th
+
+include debugging.4th
defer read
defer eval
0 nexttype !
: make-type
create nexttype @ ,
- nexttype @ 1+ nexttype !
+ 1 nexttype +!
does> @ ;
make-type fixnum-type
-make-type real-type
+make-type realnum-type
make-type boolean-type
make-type character-type
make-type string-type
create cdr-cells N allot
create cdr-type-cells N allot
+create nextfrees N allot
+:noname
+ N 0 do
+ i 1+ nextfrees i + !
+ loop
+; execute
+
variable nextfree
0 nextfree !
+: inc-nextfree
+ nextfrees nextfree @ + @
+ nextfree ! ;
+
: 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 )
\ }}}
+\ ---- Garbage Collection ---- {{{
+
+variable gc-enabled
+false gc-enabled !
+
+: gc-enable
+ true gc-enabled ! ;
+
+: gc-disable
+ 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-mark-obj ( obj -- )
+
+ pairlike? if
+ pairlike-marked? if 2drop exit then
+
+ mark-pairlike
+
+ 2dup
+
+ car recurse
+ cdr recurse
+ else
+ 2drop
+ then
+;
+
+: gc-sweep
+ N nextfree !
+ 0 N 1- do
+ nextfrees i + @ 0<> if
+ nextfree @ nextfrees i + !
+ i nextfree !
+ then
+ -1 +loop ;
+
+\ }}}
+
\ ---- Pre-defined symbols ---- {{{
objvar symbol-table
bl word
count
+ \ 2dup ." Defining primitive " type ." ..." cr
+
(create-symbol)
drop symbol-type
inc-parse-idx
repeat
- delim? if
- pop-parse-idx
- true
- else
- pop-parse-idx
- false
+ delim? pop-parse-idx
+;
+
+: realnum? ( -- bool )
+ push-parse-idx
+
+ minus? plus? or if
+ inc-parse-idx
+ then
+
+ \ Record starting parse idx:
+ \ Want to detect whether any characters (following +/-) were eaten.
+ parse-idx @
+
+ begin digit? while
+ inc-parse-idx
+ repeat
+
+ [char] . nextchar = if
+ inc-parse-idx
+ begin digit? while
+ inc-parse-idx
+ repeat
+ then
+
+ [char] e nextchar = [char] E nextchar = or if
+ inc-parse-idx
+
+ minus? plus? or if
+ inc-parse-idx
+ then
+
+ digit? invert if
+ drop pop-parse-idx false exit
+ then
+
+ begin digit? while
+ inc-parse-idx
+ repeat
then
+
+ \ This is a real number if characters were
+ \ eaten and the next characer is a delimiter.
+ parse-idx @ < delim? and
+
+ pop-parse-idx
;
: boolean? ( -- bool )
: string? ( -- bool )
nextchar [char] " = ;
-: readnum ( -- num-atom )
+: readfixnum ( -- num-atom )
plus? minus? or if
minus?
inc-parse-idx
fixnum-type
;
+: readrealnum ( -- realnum )
+
+ \ Remember that at this point we're guaranteed to
+ \ have a parsable real on this line.
+
+ parse-str parse-idx @ +
+
+ begin delim? false = while
+ inc-parse-idx
+ repeat
+
+ parse-str parse-idx @ + over -
+
+ float-parse
+
+ realnum-type
+;
+
: readbool ( -- bool-atom )
inc-parse-idx
eatspaces
fixnum? if
- readnum
+ readfixnum
+ exit
+ then
+
+ realnum? if
+ readrealnum
exit
then
eof? if
inc-parse-idx
- bold fg blue ." Moriturus te saluto." reset-term ." ok" cr
+ bold fg blue ." Moriturus te saluto." reset-term cr
quit
then
: self-evaluating? ( obj -- obj bool )
boolean-type istype? if true exit then
fixnum-type istype? if true exit then
+ realnum-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
\ ---- Print ---- {{{
-: printnum ( numobj -- ) drop 0 .R ;
+: printfixnum ( fixnumobj -- ) drop 0 .R ;
+
+: printrealnum ( realnumobj -- ) drop float-print ;
: printbool ( numobj -- )
drop if
2drop ." <compound procedure>" ;
:noname ( obj -- )
- fixnum-type istype? if printnum exit then
+ fixnum-type istype? if printfixnum exit then
+ realnum-type istype? if printrealnum exit then
boolean-type istype? if printbool exit then
character-type istype? if printchar exit then
string-type istype? if printstring exit then
cr ." Welcome to scheme.forth.jl!" cr
." Use Ctrl-D to exit." cr
+
empty-parse-str
begin
cr bold fg green ." > " reset-term
read
+
global-env obj@ eval
+
fg cyan ." ; " print reset-term
again
;