make-type symbol-type
make-type primitive-proc-type
make-type compound-proc-type
+make-type fileport-type
: istype? ( obj type -- obj bool )
over = ;
\ }}}
+\ ---- Port I/O ---- {{{
+
+: fileport>fid ( fileport -- fid )
+ drop ;
+
+: fid>fileport ( fid -- fileport )
+ fileport-type ;
+
+: open-input-file ( addr n -- fileport )
+ r/o open-file drop fid>fileport
+;
+
+: close-port ( fileport -- )
+ fileport>fid close-file drop
+;
+
+objvar console-i/o-port
+0 fileport-type console-i/o-port obj!
+
+objvar current-input-port
+console-i/o-port obj@ current-input-port obj!
+
+: read-port ( fileport -- obj )
+ current-input-port obj!
+ read ;
+
+: read-console ( -- obj )
+ console-i/o-port obj@ read-port ;
+
+\ }}}
\ ---- Pre-defined symbols ---- {{{
;
-: (create-symbol) ( addr n -- symbol-obj )
+: cstr>charlist ( addr n -- symbol-obj )
dup 0= if
2drop nil
else
bl word
count
- (create-symbol)
+ cstr>charlist
drop symbol-type
2dup
create-symbol if if-symbol
create-symbol lambda lambda-symbol
create-symbol λ λ-symbol
+create-symbol begin begin-symbol
\ }}}
\ }}}
-\ ---- 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
'\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 ! ;
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?
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
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 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? ;
extend-env ( body env )
- 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
-
- 2drop ( env body )
- car 2swap ( exp env )
+ eval-sequence
R> drop ['] eval goto-deferred \ Tail call optimization
endof
exit
then
+ begin? if
+ \ TODO
+ then
+
application? if
2over 2over
operator 2swap eval
\ }}}
+\ ---- 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