X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=scheme.4th;h=1796ea19631ff2bbad3907e675a53c2a722b5f9c;hb=7b36afd3962b8ac1389496d86da661664e03e20b;hp=8bc44d3ad9693c76273660e20f42cac8b5ac9941;hpb=215a272cf2521c34e9f8d2be62db1a35ac0a9809;p=scheme.forth.jl.git diff --git a/scheme.4th b/scheme.4th index 8bc44d3..1796ea1 100644 --- a/scheme.4th +++ b/scheme.4th @@ -3,37 +3,72 @@ scheme definitions include term-colours.4th include defer-is.4th -include catch-throw.4th +include float.4th + +include debugging.4th defer read defer eval defer print +defer collect-garbage + \ ------ Types ------ -0 constant fixnum-type -1 constant boolean-type -2 constant character-type -3 constant string-type -4 constant nil-type -5 constant pair-type -6 constant symbol-type -7 constant primitive-proc-type -8 constant compound-proc-type +variable nexttype +0 nexttype ! +: make-type + create nexttype @ , + 1 nexttype +! + does> @ ; + +make-type fixnum-type +make-type realnum-type +make-type boolean-type +make-type character-type +make-type string-type +make-type nil-type +make-type pair-type +make-type symbol-type +make-type primitive-proc-type +make-type compound-proc-type : istype? ( obj type -- obj bool ) over = ; -\ ------ Cons cell memory ------ {{{ +\ ------ List-structured memory ------ {{{ -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 +10000 constant scheme-memsize +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 @ + ! @@ -41,8 +76,7 @@ variable nextfree car-cells nextfree @ + ! nextfree @ pair-type - - 1 nextfree +! + inc-nextfree ; : car ( pair-obj -- car-obj ) @@ -105,6 +139,7 @@ variable nextfree \ }}} + \ ---- Pre-defined symbols ---- {{{ objvar symbol-table @@ -332,6 +367,8 @@ global-env obj! bl word count + \ 2dup ." Defining primitive " type ." ..." cr + (create-symbol) drop symbol-type @@ -500,13 +537,52 @@ parse-idx-stack parse-idx-sp ! 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 ) @@ -576,7 +652,7 @@ parse-idx-stack parse-idx-sp ! : string? ( -- bool ) nextchar [char] " = ; -: readnum ( -- num-atom ) +: readfixnum ( -- num-atom ) plus? minus? or if minus? inc-parse-idx @@ -596,7 +672,25 @@ parse-idx-stack parse-idx-sp ! fixnum-type ; -: readbool ( -- bool-atom ) +: 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-obj ) inc-parse-idx nextchar [char] f = if @@ -610,7 +704,7 @@ parse-idx-stack parse-idx-sp ! boolean-type ; -: readchar ( -- char-atom ) +: readchar ( -- char-obj ) inc-parse-idx inc-parse-idx @@ -713,7 +807,12 @@ parse-idx-stack parse-idx-sp ! eatspaces fixnum? if - readnum + readfixnum + exit + then + + realnum? if + readrealnum exit then @@ -769,7 +868,7 @@ parse-idx-stack parse-idx-sp ! 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 @@ -791,6 +890,7 @@ parse-idx-stack parse-idx-sp ! : 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 @@ -1059,7 +1159,9 @@ parse-idx-stack parse-idx-sp ! \ ---- Print ---- {{{ -: printnum ( numobj -- ) drop 0 .R ; +: printfixnum ( fixnumobj -- ) drop 0 .R ; + +: printrealnum ( realnumobj -- ) drop float-print ; : printbool ( numobj -- ) drop if @@ -1124,7 +1226,8 @@ parse-idx-stack parse-idx-sp ! 2drop ." " ; :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 @@ -1140,18 +1243,126 @@ parse-idx-stack parse-idx-sp ! \ }}} +\ ---- 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 + 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 + +\ }}} + \ ---- REPL ---- : repl cr ." Welcome to scheme.forth.jl!" cr ." Use Ctrl-D to exit." cr + empty-parse-str + enable-gc + begin cr bold fg green ." > " reset-term read + global-env obj@ eval + fg cyan ." ; " print reset-term again ;