X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=scheme.4th;h=12c07d2a72cbaa02dfe6f04cf54e0ef229e80420;hb=8db1ca2b987bbea36b7f1f9a1ab1baafb49fef9e;hp=3ea9d66e0598c0513ecc2595c0c202b8e3085a0f;hpb=c1614af3cb919d99081fb11d7ba2c1a83cb2d408;p=scheme.forth.jl.git diff --git a/scheme.4th b/scheme.4th index 3ea9d66..12c07d2 100644 --- a/scheme.4th +++ b/scheme.4th @@ -11,6 +11,8 @@ defer read defer eval defer print +defer collect-garbage + \ ------ Types ------ variable nexttype @@ -26,24 +28,27 @@ make-type boolean-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 N allot +create nextfrees scheme-memsize allot :noname - N 0 do + scheme-memsize 0 do i 1+ nextfrees i + ! loop ; execute @@ -53,7 +58,18 @@ variable nextfree : inc-nextfree nextfrees nextfree @ + @ - 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 @ + ! @@ -97,6 +113,9 @@ variable nextfree : nil 0 nil-type ; : nil? nil-type istype? ; +: none 0 none-type ; +: none? none-type istype? ; + : objvar create nil swap , , ; : value@ ( objvar -- val ) @ ; @@ -125,61 +144,34 @@ variable nextfree \ }}} -\ ---- Garbage Collection ---- {{{ - -variable gc-enabled -false gc-enabled ! - -: gc-enable - true gc-enabled ! ; - -: gc-disable - false gc-enabled ! ; +\ ---- Port I/O ---- {{{ -: 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 +: fileport>fid ( fileport -- fid ) + drop ; - false -; +: fid>fileport ( fid -- fileport ) + fileport-type ; -: pairlike-marked? ( obj -- obj bool ) - over nextfrees + 0= +: open-input-file ( addr n -- fileport ) + r/o open-file drop fid>fileport ; -: mark-pairlike ( obj -- obj ) - over nextfrees + 0 swap ! +: close-port ( fileport -- ) + fileport>fid close-file drop ; -: gc-mark-obj ( obj -- ) - - pairlike? if - pairlike-marked? if 2drop exit then - - mark-pairlike +objvar console-i/o-port +0 fileport-type console-i/o-port obj! - 2dup +objvar current-input-port +console-i/o-port obj@ current-input-port obj! - car recurse - cdr recurse - else - 2drop - then -; +: read-port ( fileport -- obj ) + current-input-port obj! + read ; -: gc-sweep - N nextfree ! - 0 N 1- do - nextfrees i + @ 0<> if - nextfree @ nextfrees i + ! - i nextfree ! - then - -1 +loop ; +: read-console ( -- obj ) + console-i/o-port obj@ read-port ; \ }}} @@ -247,7 +239,7 @@ objvar symbol-table ; -: (create-symbol) ( addr n -- symbol-obj ) +: cstr>charlist ( addr n -- symbol-obj ) dup 0= if 2drop nil else @@ -263,7 +255,7 @@ objvar symbol-table bl word count - (create-symbol) + cstr>charlist drop symbol-type 2dup @@ -276,13 +268,15 @@ objvar symbol-table 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 \ }}} @@ -398,65 +392,65 @@ objvar env 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 - \ 2dup ." Defining primitive " type ." ..." cr +( Look up macro in macro table. Returns nil if + no macro is found. ) +: lookup-macro ( name_symbol -- proc ) + macro-table obj@ - (create-symbol) - drop symbol-type - - 2dup + begin + nil? false = + while + 2over 2over + car car objeq? if + 2swap 2drop + car cdr + exit + then + repeat +; - symbol-table obj@ - cons - symbol-table obj! +: make-macro ( name_symbol params body env -- ) + make-procedure - rot primitive-proc-type ( var prim ) - global-env obj@ define-var -; + 2swap ( proc name_symbol ) -: arg-count-error - bold fg red ." Incorrect argument count." reset-term cr - abort -; + macro-table obj@ -: 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 + 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 -; + repeat -: arg-type-error - bold fg red ." Incorrect argument type." reset-term cr - abort -; + 2drop -: ensure-arg-type ( arg type -- arg ) - istype? false = if - arg-type-error - then + 2swap cons + macro-table obj@ cons + macro-table obj! ; -include scheme-primitives.4th - \ }}} \ ---- Read ---- {{{ @@ -487,13 +481,24 @@ parse-idx-stack parse-idx-sp ! '\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 ! ; @@ -510,12 +515,16 @@ parse-idx-stack parse-idx-sp ! 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? @@ -733,7 +742,7 @@ parse-idx-stack parse-idx-sp ! realnum-type ; -: readbool ( -- bool-atom ) +: readbool ( -- bool-obj ) inc-parse-idx nextchar [char] f = if @@ -747,7 +756,7 @@ parse-idx-stack parse-idx-sp ! boolean-type ; -: readchar ( -- char-atom ) +: readchar ( -- char-obj ) inc-parse-idx inc-parse-idx @@ -910,9 +919,9 @@ parse-idx-stack parse-idx-sp ! then eof? if + EOF character-type inc-parse-idx - bold fg blue ." Moriturus te saluto." reset-term cr - quit + exit then \ Anything else is parsed as a symbol @@ -937,6 +946,7 @@ parse-idx-stack parse-idx-sp ! 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 ; @@ -1016,6 +1026,34 @@ parse-idx-stack parse-idx-sp ! 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? ; @@ -1053,13 +1091,39 @@ parse-idx-stack parse-idx-sp ! : 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 + 2dup nil objeq? if + 2drop none + 2swap exit + then + + begin + 2dup cdr ( env explist nextexplist ) + 2dup nil objeq? 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 ) @@ -1098,32 +1162,44 @@ parse-idx-stack parse-idx-sp ! : 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 ) 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 ) + 2dup procedure-body ( argvals proc body ) + -2rot 2dup procedure-params ( body argvals proc argnames ) + -2rot procedure-env ( body argnames argvals procenv ) - extend-env ( body env ) + -2rot 2swap + flatten-proc-args + 2swap 2rot - 2swap ( env body ) - - 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 @@ -1162,6 +1238,11 @@ parse-idx-stack parse-idx-sp ! exit then + macro-definition? if + 2swap eval-define-macro + exit + then + if? if 2over 2over if-predicate @@ -1184,13 +1265,37 @@ parse-idx-stack parse-idx-sp ! 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 2dup nil objeq? 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 ( env mproc exp ) + apply 2swap ( expanded-exp env ) + + ['] eval goto-deferred + then exit then @@ -1268,6 +1373,9 @@ parse-idx-stack parse-idx-sp ! : printcomp ( primobj -- ) 2drop ." " ; +: printnone ( noneobj -- ) + 2drop ." Unspecified return value" ; + :noname ( obj -- ) fixnum-type istype? if printfixnum exit then realnum-type istype? if printrealnum exit then @@ -1279,6 +1387,7 @@ parse-idx-stack parse-idx-sp ! 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 @@ -1286,18 +1395,236 @@ 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 + 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 + +\ }}} + +\ ---- 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 2dup nil objeq? 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 + +\ }}} + +\ ---- Loading files ---- {{{ + +: charlist>cstr ( charlist addr -- n ) + + dup 2swap ( origaddr addr charlist ) + + begin + 2dup nil objeq? 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 +; + +:noname ( args -- finalResult ) + 2dup 1 ensure-arg-count + car string-type ensure-arg-type + + drop pair-type + pad charlist>cstr + pad swap load +; make-primitive load + +\ }}} + \ ---- 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 + read-console + + 2dup EOF character-type objeq? if + 2drop + bold fg blue ." Moriturus te saluto." reset-term cr + exit + then global-env obj@ eval