make-exception recoverable-exception
make-exception unrecoverable-exception
-: throw reset-term throw ;
+: throw reset-term cr throw ;
\ }}}
create cdr-cells scheme-memsize allot
create cdr-type-cells scheme-memsize allot
+variable gc-enabled
+false gc-enabled !
+
+: gc-enabled?
+ gc-enabled @ ;
+
create nextfrees scheme-memsize allot
:noname
scheme-memsize 0 do
nextfree !
nextfree @ scheme-memsize >= if
- collect-garbage
+ gc-enabled? if
+ collect-garbage
+ then
then
nextfree @ scheme-memsize >= if
: make-frame ( vars vals -- frame )
cons ;
+: add-frame-to-env ( frame env -- env )
+ cons ;
+
: frame-vars ( frame -- vars )
car ;
;
: extend-env ( vars vals env -- env )
- >R >R
- make-frame
- R> R>
- cons
+ -2rot make-frame
+ 2swap add-frame-to-env
;
-objvar vars
-objvar vals
-
-: get-vars-vals-frame ( var frame -- bool )
- 2dup frame-vars vars obj!
- frame-vals vals obj!
+: get-vals-frame ( var frame -- vals | nil )
+ 2dup frame-vars
+ 2swap frame-vals ( var vars vals )
begin
- vars obj@ nil objeq? false =
+ nil? false =
while
- 2dup vars obj@ car objeq? if
- 2drop true
+
+ -2rot ( vals var vars )
+ 2over 2over car objeq? if
+ 2drop 2drop
exit
then
- vars obj@ cdr vars obj!
- vals obj@ cdr vals obj!
+ cdr 2rot cdr
repeat
- 2drop false
+ 2drop 2drop 2drop
+ nil
;
-: get-vars-vals ( var env -- vars? vals? bool )
+: get-vals ( var env -- vals | nil )
begin
nil? false =
while
2over 2over first-frame
- get-vars-vals-frame if
- 2drop 2drop
- vars obj@ vals obj@ true
+ get-vals-frame nil? false = if
+ 2swap 2drop 2swap 2drop
exit
then
+ 2drop
+
enclosing-env
repeat
- 2drop 2drop
- false
+ 2swap 2drop
;
-hide vars
-hide vals
-
-objvar var
-
+objvar var \ Used only for error messages
: lookup-var ( var env -- val )
2over var obj!
- get-vars-vals if
- 2swap 2drop car
- else
- except-message: ." tried to read unbound variable '" var obj@ print ." '." recoverable-exception throw
+
+ get-vals nil? if
+ except-message: ." tried to read unbound variable '" var obj@ print ." '."
+ recoverable-exception throw
then
+
+ car
;
: set-var ( var val env -- )
- >R >R 2swap R> R> ( val var env )
- 2over var obj!
- get-vars-vals if
- 2swap 2drop ( val vals )
- set-car!
+ 2rot 2dup var obj! ( val env var )
+ get-vals nil? if
+ except-message: ." tried to set unbound variable '" var obj@ print ." '."
+ recoverable-exception throw
else
- except-message: ." tried to set unbound variable '" var obj@ print ." '." recoverable-exception throw
+ ( val vals )
+ set-car!
then
;
-
hide var
-objvar env
-
: define-var ( var val env -- )
- env obj!
+ first-frame ( var val frame )
+ 2rot 2swap 2over 2over ( val var frame var frame )
- 2over env obj@ ( var val var env )
- get-vars-vals if
- 2swap 2drop ( var val vals )
- set-car!
+ get-vals-frame nil? if
2drop
- else
- env obj@
- first-frame ( var val frame )
+ -2rot 2swap 2rot
add-binding
+ else
+ ( val var frame vals )
+ 2swap 2drop 2swap 2drop
+ set-car!
then
;
-hide env
-
: make-procedure ( params body env -- proc )
nil
cons cons cons
exit
then
+ nextchar [char] ) = if
+ inc-parse-idx
+ except-message: ." unmatched closing parenthesis." recoverable-exception throw
+ then
+
\ Anything else is parsed as a symbol
readsymbol charlist>symbol
\ }}}
-\ ---- Eval ---- {{{
+\ ---- Syntax ---- {{{
: self-evaluating? ( obj -- obj bool )
boolean-type istype? if true exit then
\ }}}
-\ ---- Analyze ----
+\ ---- Analyze ---- {{{
: evaluate-eproc ( eproc env --- res )
then
;
-: application-executor ( operator-proc arg-procs env -- res )
- 2rot 2over ( aprocs env fproc env )
- evaluate-eproc ( aprocs env proc )
-
- -2rot 2swap ( proc env aprocs )
- evaluate-operand-eprocs ( proc vals )
-
- 2swap ( vals proc )
-
+: apply ( vals proc )
dup case
primitive-proc-type of
drop execute
endcase
;
+: application-executor ( operator-proc arg-procs env -- res )
+ 2rot 2over ( aprocs env fproc env )
+ evaluate-eproc ( aprocs env proc )
+
+ -2rot 2swap ( proc env aprocs )
+ evaluate-operand-eprocs ( proc vals )
+
+ 2swap ( vals proc )
+
+ ['] apply goto
+;
+
: analyze-application ( exp -- eproc )
2dup operator analyze
2swap operands operand-eproc-list
; is analyze
+\ }}}
\ ---- Macro Expansion ---- {{{
except-message: ." tried to print object with unknown type." recoverable-exception throw
; is print
+xxxx
\ }}}
\ ---- Garbage Collection ---- {{{
-variable gc-enabled
-false gc-enabled !
+( Notes on garbage collection:
+ This is a mark-sweep garbage collector, invoked by cons.
+ The roots of the object tree used by the marking routine
+ include all objects in the parameter stack, and several
+ other fixed roots such as global-env, symbol-table, macro-table,
+ and the console-i/o-port.
+
+ NO OTHER OBJECTS WILL BE MARKED!
+
+ This places implicit restrictions on when cons can be invoked.
+ Invoking cons when live objects are stored on the return stack
+ or in other variables than the above will result in possible
+ memory corruption if the cons triggers the GC. )
variable gc-stack-depth
: 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
ok-symbol ( port res )
begin
+ \ DEBUG
+ \ bold fg blue ." READ from " 2over drop . ." ==> " reset-term
+
2over read-port ( port res obj )
+ \ DEBUG
+ \ 2dup print cr
+
2dup EOF character-type objeq? if
2drop 2swap close-port
exit
include scheme-primitives.4th
+ enable-gc
+
s" scheme-library.scm" load 2drop
+
+ disable-gc
\ }}}
throw false
endcase
until
+
+ disable-gc
;
forth definitions
The Lambda Lab / projects / scheme.forth.jl.git / blobdiff