altos/lisp: working on lexical scoping

Not working yet

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 129 insertions, 7 deletions

diff --git a/src/lisp/ao_lisp_const.lisp b/src/lisp/ao_lisp_const.lisp
index 5ca89bd4..621fefc4 100644
--- a/src/lisp/ao_lisp_const.lisp
+++ b/src/lisp/ao_lisp_const.lisp
@@ -1,7 +1,129 @@
-cadr (lambda (l) (car (cdr l)))
-caddr (lambda (l) (car (cdr (cdr l))))
-list (lexpr (l) l)
-1+ (lambda (x) (+ x 1))
-1- (lambda (x) (- x 1))
-last (lambda (x) (cond ((cdr x) (last (cdr x))) ((car x))))
-prog* (lexpr (l) (last l))
+					; basic list accessors
+
+
+(setq cadr (lambda (l) (car (cdr l))))
+(setq caddr (lambda (l) (car (cdr (cdr l)))))
+(setq list (lexpr (l) l))
+
+					; evaluate a list of sexprs
+
+(setq progn (lexpr (l) (last l)))
+
+					; simple math operators
+
+(setq 1+ (lambda (x) (+ x 1)))
+(setq 1- (lambda (x) (- x 1)))
+
+					; define a variable without returning the value
+
+(set 'def (macro (def-param)
+		 (list
+		  'progn
+		  (list
+		   'set
+		   (list
+		    'quote
+		    (car def-param))
+		   (cadr def-param)
+		   )
+		  (list
+		   'quote
+		   (car def-param)
+		   )
+		  )
+		 )
+     )
+
+					; define a set of local
+					; variables and then evaluate
+					; a list of sexprs
+					;
+					; (let (var-defines) sexprs)
+					;
+					; where var-defines are either
+					;
+					; (name value)
+					;
+					; or
+					;
+					; (name)
+					;
+					; e.g.
+					;
+					; (let ((x 1) (y)) (setq y (+ x 1)) y)
+
+(def let (macro (let-param)
+		((lambda (vars exprs make-names make-exprs make-nils)
+		   (progn
+
+					;
+					; make the list of names in the let
+					;
+
+		     (set 'make-names (lambda (vars)
+				       (cond (vars
+					      (cons (car (car vars))
+						    (make-names (cdr vars))))
+					     )
+				       )
+			  )
+					;
+					; the set of expressions is
+					; the list of set expressions
+					; pre-pended to the
+					; expressions to evaluate
+					;
+		     (set 'make-exprs (lambda (vars exprs)
+				       (progn
+					 (cond (vars (cons
+						      (list set
+							    (list quote
+								  (car (car vars))
+								  )
+							    (cadr (car vars))
+							    )
+						      (make-exprs (cdr vars) exprs)
+						      )
+						     )
+					       (exprs)
+					       )
+					 )
+				       )
+			  )
+		     (set 'exprs (make-exprs vars exprs))
+
+					;
+					; the parameters to the lambda is a list
+					; of nils of the right length
+					;
+		     (set 'make-nils (lambda (vars)
+				      (cond (vars (cons nil (make-nils (cdr vars))))
+					    )
+				      )
+			  )
+					;
+					; build the lambda.
+					;
+		     (set 'last-let-value 
+		     (cons
+		      (list
+		       'lambda
+		       (make-names vars)
+		       (cond ((cdr exprs) (cons 'progn exprs))
+			     ((car exprs))
+			     )
+		       )
+		      (make-nils vars)
+		      )
+		     )
+		     )
+		     
+		   )
+		 (car let-param)
+		 (cdr let-param)
+		 ()
+		 ()
+		 ()
+		 )
+		)
+     )