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
\ Symbol to be bound to welcome message procedure by library
create-symbol welcome welcome-symbol
: definition? ( obj -- obj bool )
define-symbol tagged-list? ;
-: make-lambda ( params body -- lambda-exp )
- lambda-symbol -2rot cons cons ;
-
-( Handles iterative expansion of defines in
- terms of nested lambdas. Most Schemes only
- handle one iteration of expansion! )
-: definition-var-val ( obj -- var val )
-
- cdr 2dup cdr 2swap car ( val var )
-
- begin
- symbol-type istype? false =
- while
- 2dup cdr 2swap car ( val formals var' )
- -2rot 2swap ( var' formals val )
- make-lambda nil cons ( var' val' )
- 2swap ( val' var' )
- repeat
+: definition-var ( obj -- var )
+ cdr car ;
- 2swap car
-;
+: definition-val ( obj -- val )
+ cdr cdr car ;
: eval-definition ( obj env -- res )
- 2dup 2rot ( env env obj )
- definition-var-val ( env env var val )
- 2rot eval ( env var val )
+ 2swap
+ 2over 2over
+ definition-val 2swap
+ eval
- 2rot ( var val env )
+ 2swap definition-var 2swap
+
+ 2rot
define-var
ok-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
R> drop ['] eval goto-deferred \ Tail call optimization
endof
- except-message: ." object not applicable." recoverable-exception throw
+ except-message: ." object '" drop print ." ' not applicable." recoverable-exception throw
endcase
;
-( Simply evaluates the given procedure with expbody as its argument. )
-: 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
exit
then
- begin? if
- begin-actions 2swap
- eval-sequence
- ['] eval goto-deferred
- then
-
application? if
2over 2over ( env exp env exp )
operator ( env exp env opname )
- 2dup lookup-macro nil? false = if
- \ Macro function evaluation
+ 2swap eval ( env exp proc )
- ( env exp env opname mproc )
- 2swap 2drop -2rot 2drop cdr ( env mproc body )
+ -2rot ( proc env exp )
+ operands 2swap ( proc operands env )
+ list-of-vals ( proc argvals )
- macro-expand
+ apply
+ exit
+ then
- 2swap
- ['] eval goto-deferred
- else
- \ Regular function application
+ except-message: ." tried to evaluate object with unknown type." recoverable-exception throw
+; is eval
- 2drop ( env exp env opname )
+\ }}}
- 2swap eval ( env exp proc )
+\ ---- Macro Expansion ---- {{{
- -2rot ( proc env exp )
- operands 2swap ( proc operands env )
- list-of-vals ( proc argvals )
+( Simply evaluates the given procedure with expbody as its argument. )
+: macro-eval ( 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
- apply
- exit
- then
+ extend-env eval-sequence eval
+;
+
+: expand-macro ( exp -- result )
+ pair-type istype? invert if exit then
+ 2dup car symbol-type istype? invert if 2drop exit then
+
+ lookup-macro nil? if
+ 2drop exit then
+
+ 2over cdr macro-eval
+
+ 2dup no-match-symbol objeq? if
+ 2drop exit
+ else
+ 2swap 2drop
then
- except-message: ." tried to evaluate object with unknown type." recoverable-exception throw
-; is eval
+ R> drop ['] expand goto-deferred
+;
+
+: expand-quasiquote-item ( exp -- result )
+ nil? if exit then
+
+ unquote? if
+ 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-type istype? if
+ 2dup car recurse
+ 2swap cdr recurse
+ cons
+ then
+;
+
+: expand-quasiquote ( exp -- result )
+ quasiquote-symbol 2swap cdr
+
+ expand-quasiquote-item
+
+ cons ;
+
+: expand-definition ( exp -- result )
+ define-symbol 2swap
+
+ 2dup definition-var
+ 2swap definition-val expand
+ nil ( define var val' nil )
+
+ cons cons cons ;
+
+: expand-assignment ( exp -- result )
+ set!-symbol 2swap
+
+ 2dup assignment-var
+ 2swap assignment-val expand
+ nil ( define var val' nil )
+
+ cons cons cons ;
+
+: 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
+
+ self-evaluating? if exit then
+
+ quote? if exit then
+
+ quasiquote? if expand-quasiquote exit then
+
+ definition? if expand-definition exit then
+
+ assignment? if expand-assignment exit then
+
+ macro-definition? if expand-define-macro exit then
+
+ lambda? if expand-lambda exit then
+
+ if? if expand-if exit then
+
+ application? if expand-application exit then
+
+; is expand
\ }}}
2swap 2drop ( port obj )
+ expand
+
global-env obj@ eval ( port res )
again
;
true exit
then
+ expand
+
global-env obj@ eval
fg cyan ." ; " print reset-term
The Lambda Lab / projects / scheme.forth.jl.git / blobdiff