X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=scheme.4th;h=5a049d4fe930fcff80ebd21f404f5be70dea251d;hb=35821ce20b4614368e7983ccc1132a74e5f9eacb;hp=8d28269b9c199df2aa0b5e6802d8af271bf45eed;hpb=e2e8c8f6d1d43e1044b91080f4cd3922fcd99472;p=scheme.forth.jl.git diff --git a/scheme.4th b/scheme.4th index 8d28269..5a049d4 100644 --- a/scheme.4th +++ b/scheme.4th @@ -11,6 +11,8 @@ defer read defer eval defer print +defer collect-garbage + \ ------ Types ------ variable nexttype @@ -26,16 +28,19 @@ 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 -1000 constant scheme-memsize create car-cells scheme-memsize allot create car-type-cells scheme-memsize allot create cdr-cells scheme-memsize allot @@ -53,11 +58,14 @@ variable nextfree : inc-nextfree nextfrees nextfree @ + @ + nextfree ! - dup scheme-memsize < if - nextfree ! - else - bold fg red + nextfree @ scheme-memsize >= if + collect-garbage + then + + nextfree @ scheme-memsize >= if + fg red bold ." Out of memory! Aborting." reset-term abort then @@ -105,6 +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 ) @ ; @@ -133,73 +144,37 @@ variable nextfree \ }}} -\ ---- 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 +\ ---- Port I/O ---- {{{ - false -; +: fileport>fid ( fileport -- fid ) + drop ; -: pairlike-marked? ( obj -- obj bool ) - over nextfrees + @ 0= -; +: fid>fileport ( fid -- fileport ) + fileport-type ; -: mark-pairlike ( obj -- obj ) - over nextfrees + 0 swap ! +: open-input-file ( addr n -- fileport ) + r/o open-file drop fid>fileport ; -: gc-unmark ( -- ) - scheme-memsize 0 do - 1 nextfrees i + ! - loop +: close-port ( fileport -- ) + fileport>fid close-file drop ; -defer gc-mark-trace -: gc-mark-obj ( obj -- ) - - gc-mark-trace +objvar console-i/o-port +0 fileport-type console-i/o-port obj! - pairlike? invert if 2drop exit then - pairlike-marked? if 2drop exit then +objvar current-input-port +console-i/o-port obj@ current-input-port obj! - mark-pairlike +: read-port ( fileport -- obj ) + current-input-port obj! + read ; - 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 -; +: read-console ( -- obj ) + console-i/o-port obj@ read-port ; \ }}} - - \ ---- Pre-defined symbols ---- {{{ objvar symbol-table @@ -264,7 +239,7 @@ objvar symbol-table ; -: (create-symbol) ( addr n -- symbol-obj ) +: cstr>charlist ( addr n -- symbol-obj ) dup 0= if 2drop nil else @@ -280,7 +255,7 @@ objvar symbol-table bl word count - (create-symbol) + cstr>charlist drop symbol-type 2dup @@ -293,13 +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 \ }}} @@ -421,61 +398,6 @@ global-env obj! \ }}} -\ ---- Primitives ---- {{{ - -: make-primitive ( cfa -- ) - bl word - count - - \ 2dup ." Defining primitive " type ." ..." cr - - (create-symbol) - 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 - -\ }}} - \ ---- Read ---- {{{ variable parse-idx @@ -504,13 +426,24 @@ 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 ! ; @@ -527,12 +460,16 @@ 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? @@ -750,7 +687,7 @@ parse-idx-stack parse-idx-sp ! realnum-type ; -: readbool ( -- bool-atom ) +: readbool ( -- bool-obj ) inc-parse-idx nextchar [char] f = if @@ -764,7 +701,7 @@ parse-idx-stack parse-idx-sp ! boolean-type ; -: readchar ( -- char-atom ) +: readchar ( -- char-obj ) inc-parse-idx inc-parse-idx @@ -927,9 +864,9 @@ 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 @@ -954,6 +891,7 @@ 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 ; @@ -1033,6 +971,9 @@ parse-idx-stack parse-idx-sp ! ok-symbol ; +: macro-definition? ( obj -- obj bool ) + define-macro-symbol tagged-list? ; + : if? ( obj -- obj bool ) if-symbol tagged-list? ; @@ -1076,7 +1017,39 @@ parse-idx-stack parse-idx-sp ! drop compound-proc-type ; -: application? ( obj -- obj bool) +: 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 ) pair-type istype? ; : operator ( obj -- operator ) @@ -1115,32 +1088,44 @@ 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 ) - - 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 @@ -1179,6 +1164,11 @@ parse-idx-stack parse-idx-sp ! exit then + macro-definition? if + 2swap eval-define-macro + exit + then + if? if 2over 2over if-predicate @@ -1201,13 +1191,34 @@ 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 + operator - apply + find-macro-proc nil objeq? if + \ Regular function application + + 2swap eval + -2rot + operands 2swap list-of-vals + + apply + else + \ Macro function evaluation + + 2swap 2drop 2swap ( env mproc exp ) + + apply 2swap ( expanded-exp env ) + + ['] eval goto-deferred + then exit then @@ -1285,6 +1296,9 @@ 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 @@ -1296,6 +1310,7 @@ 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 @@ -1303,35 +1318,70 @@ parse-idx-stack parse-idx-sp ! \ }}} -\ ---- DEBUGGING ---- {{{ +\ ---- Garbage Collection ---- {{{ + +variable gc-enabled +false gc-enabled ! -false value debug-mode +variable gc-stack-depth -:noname - debug-mode if - ." Object: " 2dup cr print cr - ." Pairlike: " pairlike? if - ." TRUE" - pairlike-marked? if - ." (Marked)" - else - ." (Unmarked)" - then - else - ." FALSE" - then - cr ." [paused]" - key drop cr - then -; is gc-mark-trace +: enable-gc + depth gc-stack-depth ! + true gc-enabled ! ; -: gc-mark-sweep - gc-unmark - symbol-table obj@ gc-mark-obj - global-env obj@ gc-mark-obj - gc-sweep +: 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 @@ -1339,6 +1389,7 @@ false value debug-mode loop ; +\ Debugging word - helps spot memory that is retained : gc-zero-unmarked scheme-memsize 0 do nextfrees i + @ 0<> if @@ -1348,8 +1399,134 @@ false value debug-mode 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 + +\ }}} + +\ ---- 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 ---- @@ -1357,12 +1534,19 @@ false value debug-mode 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