X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=scheme.4th;h=f96fec938b97ee8267c4b3a257cff6b62d2b8668;hb=7e44c5ca79a16106aefa315ccf38e74dcd365554;hp=0a237daf70801753b381cf6cf50f59a377f78232;hpb=1a74d57182085535faef901d6940874bea3ad3c6;p=scheme.forth.jl.git diff --git a/scheme.4th b/scheme.4th index 0a237da..f96fec9 100644 --- a/scheme.4th +++ b/scheme.4th @@ -28,6 +28,7 @@ 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 @@ -36,7 +37,7 @@ make-type fileport-type : istype? ( obj type -- obj bool ) over = ; -\ ------ List-structured memory ------ {{{ +\ ---- List-structured memory ---- {{{ 10000 constant scheme-memsize @@ -112,6 +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 ) @ ; @@ -176,7 +180,7 @@ console-i/o-port obj@ current-input-port obj! objvar symbol-table : duplicate-charlist ( charlist -- copy ) - 2dup nil objeq? false = if + nil? false = if 2dup car 2swap cdr recurse cons then ; @@ -264,13 +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 \ }}} @@ -330,7 +336,7 @@ objvar vals : 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 @@ -386,12 +392,73 @@ 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! \ }}} +\ ---- Macros ---- {{{ + +objvar macro-table + +( Look up macro in macro table. Returns nil if + no macro is found. ) +: lookup-macro ( name_symbol -- proc ) + macro-table obj@ + + begin + nil? false = + while + 2over 2over + car car objeq? if + 2swap 2drop + car cdr + exit + then + + cdr + repeat + + 2swap 2drop +; + +: 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 + repeat + + 2drop + + 2swap cons + macro-table obj@ cons + macro-table obj! +; + +\ }}} + \ ---- Read ---- {{{ variable parse-idx @@ -885,6 +952,7 @@ 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 ; @@ -964,6 +1032,34 @@ 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? ; @@ -975,7 +1071,7 @@ parse-idx-stack parse-idx-sp ! : if-alternative ( ifobj -- alt|false ) cdr cdr cdr - 2dup nil objeq? if + nil? if 2drop false else car @@ -1001,13 +1097,39 @@ 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 + 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 ) @@ -1046,41 +1168,66 @@ 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 -- 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 @@ -1110,6 +1257,11 @@ parse-idx-stack parse-idx-sp ! exit then + macro-definition? if + 2swap eval-define-macro + exit + then + if? if 2over 2over if-predicate @@ -1132,13 +1284,41 @@ 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 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 @@ -1216,6 +1396,9 @@ 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 @@ -1227,6 +1410,7 @@ 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 @@ -1321,6 +1505,7 @@ variable gc-stack-depth 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 @@ -1337,6 +1522,49 @@ variable gc-stack-depth \ }}} +\ ---- 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 -- ) @@ -1369,7 +1597,7 @@ variable gc-stack-depth arg-count-error then else - -rot 2dup nil objeq? if + -rot nil? if arg-count-error then @@ -1392,58 +1620,6 @@ 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 @@ -1459,6 +1635,7 @@ include scheme-primitives.4th read-console 2dup EOF character-type objeq? if + 2drop bold fg blue ." Moriturus te saluto." reset-term cr exit then