include debugging.4th
defer read
+defer expand
defer eval
defer print
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
: quote-body ( quote-obj -- quote-body-obj )
cdr car ;
-: quasiquote? ( obj -- obj bool )
- quasiquote-symbol tagged-list? ;
-
-: unquote? ( obj -- obj bool )
- unquote-symbol tagged-list? ;
-
-: unquote-splicing? ( obj -- obj bool )
- unquote-splicing-symbol tagged-list? ;
-
-: eval-unquote ( env obj -- res )
- cdr ( env args )
-
- nil? if
- except-message: ." no arguments to unquote." recoverable-exception throw
- then
-
- 2dup cdr
- nil? false = if
- except-message: ." too many arguments to unquote." recoverable-exception throw
- then
-
- 2drop car 2swap eval
-;
-
-( Create a new list from elements of l1 consed on to l2 )
-: join-lists ( l2 l1 -- l3 )
- nil? if 2drop exit then
-
- 2dup car
- -2rot cdr
- recurse cons
-;
-
-defer eval-quasiquote-item
-: eval-quasiquote-pair ( env obj -- res )
- 2over 2over ( env obj env obj )
-
- cdr eval-quasiquote-item
-
- -2rot car ( cdritem env objcar )
-
- unquote-splicing? if
- eval-unquote ( cdritems caritem )
-
- 2swap nil? if
- 2drop
- else
- 2swap join-lists
- then
- else
- eval-quasiquote-item ( cdritems caritem )
- 2swap cons
- then
-
-;
-
-:noname ( env obj )
- nil? if
- 2swap 2drop exit
- then
-
- unquote? if
- eval-unquote exit
- then
-
- pair-type istype? if
- eval-quasiquote-pair exit
- then
-
- 2swap 2drop
-; is eval-quasiquote-item
-
-: eval-quasiquote ( obj env -- res )
- 2swap cdr ( env args )
-
- nil? if
- except-message: ." no arguments to quasiquote." recoverable-exception throw
- then
-
- 2dup cdr ( env args args-cdr )
- nil? false = if
- except-message: ." too many arguments to quasiquote." recoverable-exception throw
- then
-
- 2drop car ( env arg )
-
- eval-quasiquote-item
-;
-
: variable? ( obj -- obj bool )
symbol-type istype? ;
: 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
- quasiquote? if
- 2swap eval-quasiquote
- exit
- then
-
variable? if
2swap lookup-var
exit
exit
then
- begin? if
- begin-actions 2swap
- eval-sequence
- ['] eval goto-deferred
- then
-
application? if
2over 2over ( env exp env exp )
extend-env eval-sequence eval
;
-defer expand
-
-: expand-quasiquote ;
-: expand-definition ;
-: expand-assignment ;
-: expand-define-macro ;
-: expand-if ;
-: expand-lambda ;
-: expand-begin ;
-: expand-application ;
-
: expand-macro ( exp -- result )
pair-type istype? invert if exit then
2dup car symbol-type istype? invert if 2drop exit then
cons cons cons ;
-:noname ( exp -- result )
+: expand-list ( exp -- res )
+ nil? if exit then
+
+ 2dup car expand
+ 2swap cdr recurse
+
+ cons ;
+
+: macro-definition-nameparams
+ cdr car ;
+
+: expand-define-macro ( exp -- res )
+ define-macro-symbol 2swap
+ 2dup macro-definition-nameparams
+ 2swap macro-definition-body expand-list
+
+ cons cons ;
+
+: expand-lambda ( exp -- res )
+ lambda-symbol 2swap
+ 2dup lambda-parameters
+ 2swap lambda-body expand-list
+
+ cons cons ;
+
+: expand-if ( exp -- res )
+ if-symbol 2swap
+
+ 2dup if-predicate expand
+ 2swap 2dup if-consequent expand
+ 2swap if-alternative none? if
+ 2drop nil
+ else
+ expand nil cons
+ then
+
+ cons cons cons ;
+
+: expand-application ( exp -- res )
+ 2dup operator expand
+ 2swap operands expand-list
+
+ cons ;
+:noname ( exp -- result )
expand-macro
- quote? if exit then
+ self-evaluating? if exit then
- quasiquote? if expand-quasiquote exit then
+ quote? if exit then
definition? if expand-definition exit then
macro-definition? if expand-define-macro exit then
- if? if expand-if exit then
-
lambda? if expand-lambda exit then
- begin? if expand-begin exit then
+ if? if expand-if exit then
application? if expand-application exit then
include scheme-primitives.4th
- s" scheme-derived-forms.scm" load 2drop
-
-\ s" scheme-library.scm" load 2drop
+ s" testing-library.scm" load 2drop
+ \ s" scheme-library.scm" load 2drop
\ }}}
enable-gc
\ Display welcome message
- \ welcome-symbol nil cons global-env obj@ eval 2drop
+ welcome-symbol nil cons global-env obj@ eval 2drop
begin
['] repl-body catch