include term-colours.4th
include defer-is.4th
+include goto.4th
include catch-throw.4th
include integer.4th
include float.4th
include debugging.4th
defer read
+defer expand
+defer analyze
defer eval
defer print
R> R>
;
+: 2pick ( an bn an-1 bn-1 ... a0 b0 n -- an bn an-1 bn-1 ... a0 b0 an bn )
+ 2* 1+ dup
+ >R pick R> pick ;
+
\ }}}
\ ---- Pre-defined symbols ---- {{{
create-symbol if if-symbol
create-symbol lambda lambda-symbol
create-symbol λ λ-symbol
-create-symbol begin begin-symbol
create-symbol eof eof-symbol
create-symbol no-match no-match-symbol
: lambda-body ( obj -- body )
cdr cdr ;
-: 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
exit
then
- begin? if
- begin-actions 2swap
- eval-sequence
- ['] eval goto-deferred
- then
-
application? if
2over 2over ( env exp env exp )
\ }}}
+\ ---- Analyze ----
+
+: evaluate-eproc ( env eproc --- res )
+ begin
+ nil? invert
+ while
+ 2dup car
+ 2swap cdr
+ repeat
+
+ 2drop \ get rid of null
+
+ \ Final element of eproc list is primitive procedure
+ drop \ dump type signifier
+ goto \ jump straight to primitive procedure (executor)
+;
+
+: self-evaluating-executor ( env exp -- exp )
+ 2swap 2drop ;
+
+: analyze-self-evaluating ( exp --- eproc )
+ ['] self-evaluating-executor primitive-proc-type
+ nil cons cons
+;
+
+: quote-executor ( env exp -- exp )
+ 2swap 2drop ;
+
+: analyze-quoted ( exp -- eproc )
+ quote-body
+
+ ['] quote-executor primitive-proc-type
+ nil cons cons
+;
+
+: variable-executor ( env var -- val )
+ 2swap lookup-var ;
+
+: analyze-variable ( exp -- eproc )
+ ['] variable-executor primitive-proc-type
+ nil cons cons
+;
+
+: definition-executor ( env var val-eproc -- ok )
+ 2rot 2dup 2rot ( var env env val-eproc )
+ evaluate-eproc 2swap ( var val env )
+ define-var
+ ok-symbol
+;
+
+: analyze-definition ( exp -- eproc )
+ 2dup definition-var
+ 2swap definition-val analyze
+
+ ['] definition-executor primitive-proc-type
+ nil cons cons cons
+;
+
+: assignment-executor ( env var val-eproc -- ok )
+ 2rot 2dup 2rot ( var env env val-eproc )
+ evaluate-eproc 2swap ( var val env )
+ set-var
+ ok-symbol
+;
+
+: analyze-assignment ( exp -- eproc )
+ 2dup assignment-var
+ 2swap assignment-val analyze ( var val-eproc )
+
+ ['] assignment-executor primitive-proc-type
+ nil cons cons cons
+;
+
+: if-executor ( env pproc cproc aproc -- res )
+ 2rot 3 2pick 2swap ( env cproc aproc env pproc )
+ evaluate-eproc
+ true? if
+ 2drop evaluate-eproc
+ else
+ 2swap 2drop evaluate-eproc
+ then
+;
+
+: analyze-if ( exp -- eproc )
+ 2dup if-predicate analyze
+ 2swap 2dup if-consequent analyze
+ 2swap if-alternative analyze
+
+ ['] if-executor primitive-proc-type
+ nil cons cons cons cons
+;
+
+: sequential-executor ( env eproc1 eproc2 -- res )
+ 2swap 2 2pick 2swap ( env eproc2 env eproc1 )
+ evaluate-eproc 2drop
+ evaluate-eproc
+;
+
+: analyze-sequence ( explist -- eproc )
+ nil? if
+ except-message: ." Tried to analyze empty expression sequence." recoverable-exception throw
+ then
+
+ 2dup car analyze
+ 2swap cdr
+ nil? if
+ 2drop
+ else
+ recurse
+ ['] sequential-executor
+ nil cons cons
+ then
+;
+
+: lambda-executor ( env params bproc -- res )
+ 2rot make-procedure
+ ( Although this is packaged up as a regular compound procedure,
+ the "body" element contains an _eproc_ to be evaluated in an
+ environment resulting from extending env with the parameter
+ bindings. )
+;
+
+: analyze-lambda ( exp -- eproc )
+ 2dup lambda-parameters
+ 2swap lambda-body analyze-sequence
+
+ ['] lambda-executor primitive-proc-type
+ nil cons cons cons
+;
+
+:noname ( exp --- eproc )
+
+ self-evaluating? if
+ analyze-self-evaluating
+ exit
+ then
+
+ quote? if
+ analyze-quoted
+ exit
+ then
+
+ variable? if
+ analyze-variable
+ exit
+ then
+
+ definition? if
+ analyze-definition
+ exit
+ then
+
+ assignment? if
+ analyze-assignment
+ exit
+ then
+
+ if? if
+ analyze-if
+ exit
+ then
+
+ lambda? if
+ analyze-lambda
+ exit
+ then
+
+; is analyze
+
+
\ ---- Macro Expansion ---- {{{
( Simply evaluates the given procedure with expbody as its argument. )
extend-env eval-sequence eval
;
-defer expand
-
: expand-macro ( exp -- result )
pair-type istype? invert if exit then
2dup car symbol-type istype? invert if 2drop exit then
nil? if exit then
unquote? if
- unquote-symbol 2swap cdr expand nil cons cons
+ unquote-symbol 2swap cdr car expand nil cons cons
+ exit
+ then
+
+ unquote-splicing? if
+ unquote-splicing-symbol 2swap cdr car expand nil cons cons
exit
then
- pair? if
+ pair-type istype? if
2dup car recurse
2swap cdr recurse
cons
2swap if-alternative none? if
2drop nil
else
- nil cons
+ expand nil cons
then
cons cons cons ;
-: expand-begin ( exp -- res )
- begin-symbol 2swap
- begin-actions expand-list
-
- cons ;
-
: expand-application ( exp -- res )
- 2dup operator
+ 2dup operator expand
2swap operands expand-list
cons ;
:noname ( exp -- result )
-
expand-macro
self-evaluating? if exit then
if? if expand-if exit then
- begin? if expand-begin exit then
-
application? if expand-application exit then
; is expand
include scheme-primitives.4th
- s" scheme-derived-forms.scm" load 2drop
-
-\ s" scheme-library.scm" load 2drop
+ \ s" scheme-library.scm" load 2drop
\ }}}
The Lambda Lab / projects / scheme.forth.jl.git / blobdiff