X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=src%2Flisp%2Fao_lisp_const.lisp;h=5c1aa75be79f983bfdab5c019286feea9c82ac3a;hb=835bf4131f9e20575bfdf2179462ebdf54a14761;hp=d9b1c1f2ed3e250cb21fcb1dae899e53594917bb;hpb=e1acf5eb12aceda7aa838df031c1da1129d0fa5d;p=fw%2Faltos

diff --git a/src/lisp/ao_lisp_const.lisp b/src/lisp/ao_lisp_const.lisp
index d9b1c1f2..5c1aa75b 100644
--- a/src/lisp/ao_lisp_const.lisp
+++ b/src/lisp/ao_lisp_const.lisp
@@ -14,100 +14,320 @@
 ; Lisp code placed in ROM
 
 					; return a list containing all of the arguments
-
 (set (quote list) (lexpr (l) l))
 
-					;
-					; Define a variable without returning the value
-					; Useful when defining functions to avoid
-					; having lots of output generated
-					;
+(set (quote set!)
+     (macro (name value rest)
+	    (list
+	     set
+	     (list
+	      quote
+	      name)
+	     value)
+	    )
+     )
 
-(set (quote define) (macro (name val rest)
-			(list
-			 'progn
-			 (list
-			  'set
-			  (list 'quote name)
-			  val)
-			 (list 'quote name)
-			 )
-			)
+(set! append
+     (lexpr (args)
+	    ((lambda (append-list append-lists)
+	       (set! append-list
+		    (lambda (a b)
+		      (cond ((null? a) b)
+			    (else (cons (car a) (append-list (cdr a) b)))
+			    )
+		      )
+		    )
+	       (set! append-lists
+		    (lambda (lists)
+		      (cond ((null? lists) lists)
+			    ((null? (cdr lists)) (car lists))
+			    (else (append-list (car lists) (append-lists (cdr lists))))
+			    )
+		      )
+		    )
+	       (append-lists args)
+	       ) () ())
+	    )
+     )
+
+(append '(a b c) '(d e f) '(g h i))
+
+					; boolean operators
+
+(set! or
+     (macro (l)
+	    ((lambda (_or)
+	       (set! _or
+		    (lambda (l)
+		      (cond ((null? l) #f)
+			    ((null? (cdr l))
+			     (car l))
+			    (else
+			     (list
+			      cond
+			      (list
+			       (car l))
+			      (list
+			       'else
+			       (_or (cdr l))
+			       )
+			      )
+			     )
+			    )
+		      )
+		    )
+	       (_or l)) ())))
+
+					; execute to resolve macros
+
+(or #f #t)
+
+
+(set! and
+     (macro (l)
+	    ((lambda (_and)
+	       (set! _and
+		    (lambda (l)
+		      (cond ((null? l) #t)
+			    ((null? (cdr l))
+			     (car l))
+			    (else
+			     (list
+			      cond
+			      (list
+			       (car l)
+			       (_and (cdr l))
+			       )
+			      )
+			     )
+			    )
+		      )
+		    )
+	       (_and l)) ())
+	    )
      )
 
+
+					; execute to resolve macros
+
+(and #t #f)
+
+(set! quasiquote
+  (macro (x rest)
+	 ((lambda (constant? combine-skeletons expand-quasiquote)
+	    (set! constant?
+					; A constant value is either a pair starting with quote,
+					; or anything which is neither a pair nor a symbol
+
+		 (lambda (exp)
+		   (cond ((pair? exp)
+			  (eq? (car exp) 'quote)
+			  )
+			 (else
+			  (not (symbol? exp))
+			  )
+			 )
+		   )
+		 )
+	    (set! combine-skeletons
+		 (lambda (left right exp)
+		   (cond
+		    ((and (constant? left) (constant? right)) 
+		     (cond ((and (eqv? (eval left) (car exp))
+				 (eqv? (eval right) (cdr exp)))
+			    (list 'quote exp)
+			    )
+			   (else
+			    (list 'quote (cons (eval left) (eval right)))
+			    )
+			   )
+		     )
+		    ((null? right)
+		     (list 'list left)
+		     )
+		    ((and (pair? right) (eq? (car right) 'list))
+		     (cons 'list (cons left (cdr right)))
+		     )
+		    (else
+		     (list 'cons left right)
+		     )
+		    )
+		   )
+		 )
+
+	    (set! expand-quasiquote
+		 (lambda (exp nesting)
+		   (cond
+
+					; non cons -- constants
+					; themselves, others are
+					; quoted
+
+		    ((not (pair? exp)) 
+		     (cond ((constant? exp)
+			    exp
+			    )
+			   (else
+			    (list 'quote exp)
+			    )
+			   )
+		     )
+
+					; check for an unquote exp and
+					; add the param unquoted
+
+		    ((and (eq? (car exp) 'unquote) (= (length exp) 2))
+		     (cond ((= nesting 0)
+			    (car (cdr exp))
+			    )
+			   (else
+			    (combine-skeletons ''unquote 
+					       (expand-quasiquote (cdr exp) (- nesting 1))
+					       exp))
+			   )
+		     )
+
+					; nested quasi-quote --
+					; construct the right
+					; expression
+
+		    ((and (eq? (car exp) 'quasiquote) (= (length exp) 2))
+		     (combine-skeletons ''quasiquote 
+					(expand-quasiquote (cdr exp) (+ nesting 1))
+					exp))
+
+					; check for an
+					; unquote-splicing member,
+					; compute the expansion of the
+					; value and append the rest of
+					; the quasiquote result to it
+
+		    ((and (pair? (car exp))
+			  (eq? (car (car exp)) 'unquote-splicing)
+			  (= (length (car exp)) 2))
+		     (cond ((= nesting 0)
+			    (list 'append (car (cdr (car exp)))
+				  (expand-quasiquote (cdr exp) nesting))
+			    )
+			   (else
+			    (combine-skeletons (expand-quasiquote (car exp) (- nesting 1))
+					       (expand-quasiquote (cdr exp) nesting)
+					       exp))
+			   )
+		     )
+
+					; for other lists, just glue
+					; the expansion of the first
+					; element to the expansion of
+					; the rest of the list
+
+		    (else (combine-skeletons (expand-quasiquote (car exp) nesting)
+					     (expand-quasiquote (cdr exp) nesting)
+					     exp)
+			  )
+		    )
+		   )
+		 )
+	    (expand-quasiquote x 0)
+	    ) () () ())
+	 )
+  )
 					;
-					; A slightly more convenient form
-					; for defining lambdas.
+					; Define a variable without returning the value
+					; Useful when defining functions to avoid
+					; having lots of output generated.
 					;
-					; (defun <name> (<params>) s-exprs)
+					; Also accepts the alternate
+					; form for defining lambdas of
+					; (define (name x y z) sexprs ...) 
 					;
 
-(define defun (macro (name args exprs)
-		  (list
-		   define
-		   name
-		   (cons 'lambda (cons args exprs))
+(set! define
+      (macro (first rest)
+
+					; check for alternate lambda definition form
+
+	     (cond ((list? first)
+		    (set! rest
+			  (append
+			   (list
+			    'lambda
+			    (cdr first))
+			   rest))
+		    (set! first (car first))
+		    )
+		   (else
+		    (set! rest (car rest))
+		    )
 		   )
-		  )
-     )
+	     `(begin
+	       (set! ,first ,rest)
+	       (quote ,first))
+	     )
+      )
 
 					; basic list accessors
 
 
-(defun caar (l) (car (car l)))
+(define (caar l) (car (car l)))
 
-(defun cadr (l) (car (cdr l)))
+(define (cadr l) (car (cdr l)))
 
-(defun caddr (l) (car (cdr (cdr l))))
+(define (cdar l) (cdr (car l)))
 
-(defun nth (list n)
-  (cond ((= n 0) (car list))
-	((nth (cdr list) (1- n)))
-	)
+(define (caddr l) (car (cdr (cdr l))))
+
+(define (list-tail x k)
+  (if (zero? k)
+      x
+    (list-tail (cdr x (- k 1)))
+    )
   )
 
-					; simple math operators
+(define (list-ref x k)
+  (car (list-tail x k))
+  )
 
-(defun 1+ (x) (+ x 1))
-(defun 1- (x) (- x 1))
+					; (if <condition> <if-true>)
+					; (if <condition> <if-true> <if-false)
 
-(define zero? (macro (value rest)
-		     (list
-		      eq?
-		      value
-		      0)
-		     )
+(define if
+  (macro (test args)
+	 (cond ((null? (cdr args))
+		`(cond (,test ,(car args)))
+		)
+	       (else
+		`(cond (,test ,(car args))
+		       (else ,(cadr args)))
+		)
+	       )
+	 )
   )
 
+(if (> 3 2) 'yes)
+(if (> 3 2) 'yes 'no)
+(if (> 2 3) 'no 'yes)
+(if (> 2 3) 'no)
+
+					; simple math operators
+
+(define zero? (macro (value rest) `(eq? ,value 0)))
+
 (zero? 1)
 (zero? 0)
 (zero? "hello")
 
-(define positive? (macro (value rest)
-			 (list
-			  >
-			  value
-			  0)
-			 )
-  )
+(define positive? (macro (value rest) `(> ,value 0)))
 
 (positive? 12)
 (positive? -12)
 
-(define negative? (macro (value rest)
-			 (list
-			  <
-			  value
-			  0)
-			 )
-  )
+(define negative? (macro (value rest) `(< ,value 0)))
 
 (negative? 12)
 (negative? -12)
 
-(defun abs (x) (cond ((>= x 0) x)
-		     (else (- x)))
-       )
+(define (abs x) (if (>= x 0) x (- x)))
 
 (abs 12)
 (abs -12)
@@ -138,53 +358,92 @@
 (min 1 2 3)
 (min 3 2 1)
 
-(defun even? (x) (zero? (% x 2)))
+(define (even? x) (zero? (% x 2)))
 
 (even? 2)
 (even? -2)
 (even? 3)
 (even? -1)
 
-(defun odd? (x) (not (even? x)))
+(define (odd? x) (not (even? x)))
 
 (odd? 2)
 (odd? -2)
 (odd? 3)
 (odd? -1)
 
-(define exact? number?)
-(defun inexact? (x) #f)
 
-					; (if <condition> <if-true>)
-					; (if <condition> <if-true> <if-false)
+					; define a set of local
+					; variables all at once 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)) (set! y (+ x 1)) y)
 
-(define if (macro (test args)
-	       (cond ((null? (cdr args))
-		      (list
-		       cond
-		       (list test (car args)))
-		      )
-		     (else
-		      (list
-		       cond
-		       (list test (car args))
-		       (list 'else (cadr args))
-		       )
-		      )
-		     )
-	       )
+(define let (macro (vars exprs)
+		((lambda (make-names make-vals)
+
+					;
+					; make the list of names in the let
+					;
+
+		   (set! make-names (lambda (vars)
+				      (cond ((not (null? vars))
+					     (cons (car (car vars))
+						   (make-names (cdr vars))))
+					    (else ())
+					    )
+				      )
+			 )
+
+					; the parameters to the lambda is a list
+					; of nils of the right length
+
+		   (set! make-vals (lambda (vars)
+				     (cond ((not (null? vars))
+					    (cons (cond ((null? (cdr (car vars))) ())
+							(else
+							 (car (cdr (car vars))))
+							)
+						  (make-vals (cdr vars))))
+					   (else ())
+					   )
+				     )
+			 )
+					; prepend the set operations
+					; to the expressions
+
+					; build the lambda.
+
+		   `((lambda ,(make-names vars) ,@exprs) ,@(make-vals vars))
+		   )
+		 ()
+		 ()
+		 )
+		)
      )
+		   
 
-(if (> 3 2) 'yes)
-(if (> 3 2) 'yes 'no)
-(if (> 2 3) 'no 'yes)
-(if (> 2 3) 'no)
+(let ((x 1) (y)) (set! y 2) (+ x y))
 
 					; define a set of local
-					; variables and then evaluate
-					; a list of sexprs
+					; variables one at a time and
+					; then evaluate a list of
+					; sexprs
 					;
-					; (let (var-defines) sexprs)
+					; (let* (var-defines) sexprs)
 					;
 					; where var-defines are either
 					;
@@ -196,9 +455,9 @@
 					;
 					; e.g.
 					;
-					; (let ((x 1) (y)) (set! y (+ x 1)) y)
+					; (let* ((x 1) (y)) (set! y (+ x 1)) y)
 
-(define let (macro (vars exprs)
+(define let* (macro (vars exprs)
 		((lambda (make-names make-exprs make-nils)
 
 					;
@@ -209,6 +468,7 @@
 				      (cond ((not (null? vars))
 					     (cons (car (car vars))
 						   (make-names (cdr vars))))
+					    (else ())
 					    )
 				      )
 			 )
@@ -231,7 +491,7 @@
 					      (make-exprs (cdr vars) exprs)
 					      )
 					     )
-					    (exprs)
+					    (else exprs)
 					    )
 				      )
 			 )
@@ -241,6 +501,7 @@
 
 		   (set! make-nils (lambda (vars)
 				     (cond ((not (null? vars)) (cons () (make-nils (cdr vars))))
+					   (else ())
 					   )
 				     )
 			 )
@@ -251,9 +512,7 @@
 
 					; build the lambda.
 
-		   (cons (cons 'lambda (cons (make-names vars) exprs))
-			 (make-nils vars)
-			 )
+		   `((lambda ,(make-names vars) ,@exprs) ,@(make-nils vars))
 		   )
 		 ()
 		 ()
@@ -262,67 +521,17 @@
 		)
      )
 
-(let ((x 1)) x)
+(let* ((x 1)) x)
 
-					; boolean operators
+(define when (macro (test l) `(cond (,test ,@l))))
 
-(define or (lexpr (l)
-	       (let ((ret #f))
-		 (while (not (null? l))
-		   (cond ((car l) (set! ret #t) (set! l ()))
-			 ((set! l (cdr l)))))
-		 ret
-		 )
-	       )
-     )
+(when #t (write 'when))
 
-					; execute to resolve macros
+(define unless (macro (test l) `(cond ((not ,test) ,@l))))
 
-(or #f #t)
+(unless #f (write 'unless))
 
-(define and (lexpr (l)
-	       (let ((ret #t))
-		 (while (not (null? l))
-		   (cond ((car l)
-			  (set! l (cdr l)))
-			 (#t
-			  (set! ret #f)
-			  (set! l ()))
-			 )
-		   )
-		 ret
-		 )
-	       )
-     )
-
-					; execute to resolve macros
-
-(and #t #f)
-
-
-(define append (lexpr (args)
-		      (let ((append-list (lambda (a b)
-					   (cond ((null? a) b)
-						 (else (cons (car a) (append-list (cdr a) b)))
-						 )
-					   )
-					 )
-			    (append-lists (lambda (lists)
-					    (cond ((null? lists) lists)
-						  ((null? (cdr lists)) (car lists))
-						  (else (append-list (car lists) (append-lists (cdr lists))))
-						  )
-					    )
-					  )
-			    )
-			(append-lists args)
-			)
-		      )
-  )
-
-(append '(a b c) '(d e f) '(g h i))
-
-(defun reverse (list)
+(define (reverse list)
   (let ((result ()))
     (while (not (null? list))
       (set! result (cons (car list) result))
@@ -333,22 +542,20 @@
 
 (reverse '(1 2 3))
 
-(define list-tail
-  (lambda (x k)
-    (if (zero? k)
-	x
-      (list-tail (cdr x) (- k 1)))))
+(define (list-tail x k)
+  (if (zero? k)
+      x
+    (list-tail (cdr x) (- k 1)))))
 
 (list-tail '(1 2 3) 2)
 
-(defun list-ref (x k) (car (list-tail x k)))
+(define (list-ref x k) (car (list-tail x k)))
 
 (list-ref '(1 2 3) 2)
-
     
 					; recursive equality
 
-(defun equal? (a b)
+(define (equal? a b)
   (cond ((eq? a b) #t)
 	((and (pair? a) (pair? b))
 	 (and (equal? (car a) (car b))
@@ -361,32 +568,41 @@
 (equal? '(a b c) '(a b c))
 (equal? '(a b c) '(a b b))
 
-(defun _member (obj list test?)
-  (if (null? list)
-      #f
-    (if (test? obj (car list))
-	list
-      (memq obj (cdr list)))))
+(define member (lexpr (obj list test?)
+		      (cond ((null? list)
+			     #f
+			     )
+			    (else
+			     (if (null? test?) (set! test? equal?) (set! test? (car test?)))
+			     (if (test? obj (car list))
+				 list
+			       (member obj (cdr list) test?))
+			     )
+			    )
+		      )
+  )
+
+(member '(2) '((1) (2) (3)))
+
+(member '(4) '((1) (2) (3)))
 
-(defun memq (obj list) (_member obj list eq?))
+(define (memq obj list) (member obj list eq?))
 
 (memq 2 '(1 2 3))
 
 (memq 4 '(1 2 3))
 
-(defun memv (obj list) (_member obj list eqv?))
+(memq '(2) '((1) (2) (3)))
+
+(define (memv obj list) (member obj list eqv?))
 
 (memv 2 '(1 2 3))
 
 (memv 4 '(1 2 3))
 
-(defun member (obj list) (_member obj list equal?))
-
-(member '(2) '((1) (2) (3)))
+(memv '(2) '((1) (2) (3)))
 
-(member '(4) '((1) (2) (3)))
-
-(defun _assoc (obj list test?)
+(define (_assoc obj list test?)
   (if (null? list)
       #f
     (if (test? obj (caar list))
@@ -396,9 +612,9 @@
     )
   )
 
-(defun assq (obj list) (_assoc obj list eq?))
-(defun assv (obj list) (_assoc obj list eqv?))
-(defun assoc (obj list) (_assoc obj list equal?))
+(define (assq obj list) (_assoc obj list eq?))
+(define (assv obj list) (_assoc obj list eqv?))
+(define (assoc obj list) (_assoc obj list equal?))
 
 (assq 'a '((a 1) (b 2) (c 3)))
 (assv 'b '((a 1) (b 2) (c 3)))
@@ -409,52 +625,52 @@
 (char? #\q)
 (char? "h")
 
-(defun char-upper-case? (c) (<= #\A c #\Z))
+(define (char-upper-case? c) (<= #\A c #\Z))
 
 (char-upper-case? #\a)
 (char-upper-case? #\B)
 (char-upper-case? #\0)
 (char-upper-case? #\space)
 
-(defun char-lower-case? (c) (<= #\a c #\a))
+(define (char-lower-case? c) (<= #\a c #\a))
 
 (char-lower-case? #\a)
 (char-lower-case? #\B)
 (char-lower-case? #\0)
 (char-lower-case? #\space)
 
-(defun char-alphabetic? (c) (or (char-upper-case? c) (char-lower-case? c)))
+(define (char-alphabetic? c) (or (char-upper-case? c) (char-lower-case? c)))
 
 (char-alphabetic? #\a)
 (char-alphabetic? #\B)
 (char-alphabetic? #\0)
 (char-alphabetic? #\space)
 
-(defun char-numeric? (c) (<= #\0 c #\9))
+(define (char-numeric? c) (<= #\0 c #\9))
 
 (char-numeric? #\a)
 (char-numeric? #\B)
 (char-numeric? #\0)
 (char-numeric? #\space)
 
-(defun char-whitespace? (c) (or (<= #\tab c #\return) (= #\space c)))
+(define (char-whitespace? c) (or (<= #\tab c #\return) (= #\space c)))
 
 (char-whitespace? #\a)
 (char-whitespace? #\B)
 (char-whitespace? #\0)
 (char-whitespace? #\space)
 
-(defun char->integer (c) c)
-(defun integer->char (c) char-integer)
+(define (char->integer c) c)
+(define (integer->char c) char-integer)
 
-(defun char-upcase (c) (if (char-lower-case? c) (+ c (- #\A #\a)) c))
+(define (char-upcase c) (if (char-lower-case? c) (+ c (- #\A #\a)) c))
 
 (char-upcase #\a)
 (char-upcase #\B)
 (char-upcase #\0)
 (char-upcase #\space)
 
-(defun char-downcase (c) (if (char-upper-case? c) (+ c (- #\a #\A)) c))
+(define (char-downcase c) (if (char-upper-case? c) (+ c (- #\a #\A)) c))
 
 (char-downcase #\a)
 (char-downcase #\B)
@@ -463,23 +679,21 @@
 
 (define string (lexpr (chars) (list->string chars)))
 
-(patom "apply\n")
+(display "apply\n")
 (apply cons '(a b))
 
-(define save ())
-
 (define map (lexpr (proc lists)
-		   (let ((args (lambda (lists)
-				 (if (null? lists) ()
-				   (cons (caar lists) (args (cdr lists))))))
-			 (next (lambda (lists)
-				 (if (null? lists) ()
-				   (cons (cdr (car lists)) (next (cdr lists))))))
-			 (domap (lambda (lists)
-				  (if (null? (car lists)) ()
-				    (cons (apply proc (args lists)) (domap (next lists)))
-					)))
-			 )
+		   (let* ((args (lambda (lists)
+				  (if (null? lists) ()
+				    (cons (caar lists) (args (cdr lists))))))
+			  (next (lambda (lists)
+				  (if (null? lists) ()
+				    (cons (cdr (car lists)) (next (cdr lists))))))
+			  (domap (lambda (lists)
+				   (if (null? (car lists)) ()
+				     (cons (apply proc (args lists)) (domap (next lists)))
+				     )))
+			  )
 		     (domap lists))))
 
 (map cadr '((a b) (d e) (g h)))
@@ -488,33 +702,94 @@
 			(apply map proc lists)
 			#t))
 
-(for-each patom '("hello" " " "world" "\n"))
+(for-each display '("hello" " " "world" "\n"))
+
+(define _string-ml (lambda (strings)
+			     (if (null? strings) ()
+			       (cons (string->list (car strings)) (_string-ml (cdr strings))))))
 
 (define string-map (lexpr (proc strings)
-			  (let ((make-lists (lambda (strings)
-					      (if (null? strings) ()
-						(cons (string->list (car strings)) (make-lists (cdr strings))))))
-				)
-			    (list->string (apply map proc (make-lists strings))))))
+			  (list->string (apply map proc (_string-ml strings))))))
 
-(string-map 1+ "HAL")
+(string-map (lambda (x) (+ 1 x)) "HAL")
 
 (define string-for-each (lexpr (proc strings)
-			       (apply string-map proc strings)
-			       #t))
+			       (apply for-each proc (_string-ml strings))))
+
+(string-for-each write-char "IBM\n")
 
-(string-for-each patom "IBM")
+(define newline (lambda () (write-char #\newline)))
 
+(newline)
 
 (call-with-current-continuation
  (lambda (exit)
    (for-each (lambda (x)
-	       (print "test" x)
+	       (write "test" x)
 	       (if (negative? x)
 		   (exit x)))
 	     '(54 0 37 -3 245 19))
    #t))
 
+
+					; `q -> (quote q)
+					; `(q) -> (append (quote (q)))
+					; `(a ,(+ 1 2)) -> (append (quote (a)) (list (+ 1 2)))
+					; `(a ,@(list 1 2 3) -> (append (quote (a)) (list 1 2 3))
+
+
+
+`(hello ,(+ 1 2) ,@(list 1 2 3) `foo)
+
+(define repeat (macro (count rest)
+		       `(let ((__count__ ,count))
+			  (while (<= 0 (set! __count__ (- __count__ 1))) ,@rest))))
+
+(repeat 2 (write 'hello))
+(repeat 3 (write 'goodbye))
+
+(define case (macro (test l)
+		    (let* ((_unarrow
+					; construct the body of the
+					; case, dealing with the
+					; lambda version ( => lambda)
+			    
+			    (lambda (l)
+			      (cond ((null? l) l)
+				    ((eq? (car l) '=>) `(( ,(cadr l) __key__)))
+				    (else l))))
+			   (_case (lambda (l)
+
+					; Build the case elements, which is
+					; simply a list of cond clauses
+
+				    (cond ((null? l) ())
+
+					; else case
+
+					  ((eq? (caar l) 'else)
+					   `((else ,@(_unarrow (cdr (car l))))))
+
+					; regular case
+					  
+					  (else
+					   (cons
+					    `((eqv? ,(caar l) __key__)
+					      ,@(_unarrow (cdr (car l))))
+					    (_case (cdr l)))
+					   )
+					  ))))
+
+					; now construct the overall
+					; expression, using a lambda
+					; to hold the computed value
+					; of the test expression
+
+		      `((lambda (__key__)
+			  (cond ,@(_case l))) ,test))))
+
+(case 12 (1 "one") (2 "two") (3 => (lambda (x) (write "the value is" x))) (12 "twelve") (else "else"))
+
 ;(define number->string (lexpr (arg opt)
 ;			      (let ((base (if (null? opt) 10 (car opt)))
 					;