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ref: eceeddf6d218e12cefb36fb9594c29be37852dd2
parent: c61dc10002d41b6be70bd328038eef014f293074
author: JeffBezanson <[email protected]>
date: Sun Jul 26 23:34:33 EDT 2009

adding support for optional arguments
error checking formal argument lists
making filter preserve the order of elements in the input list


--- a/femtolisp/ast/rpasses-out.lsp
+++ b/femtolisp/ast/rpasses-out.lsp
@@ -5,25 +5,31 @@
 						       (*named* class (r-call
   c "POSIXt" "POSIXct")))))))
 	       (<- Sys.timezone (lambda ()
-				  (let () (r-block (r-call as.vector (r-call
-  Sys.getenv "TZ"))))))
+				  (let ()
+				       (r-block (r-call as.vector (r-call
+								   Sys.getenv
+								   "TZ"))))))
 	       (<- as.POSIXlt (lambda (x tz)
-				(let ((x ()) (tzone ()) (fromchar ()) (tz ()))
+				(let ((x ())
+				      (tzone ())
+				      (fromchar ())
+				      (tz ()))
 				     (r-block (when (missing tz)
 						    (<- tz ""))
 					      (<- fromchar (lambda (x)
-							     (let ((res ()) (f
-  ())
-  (j ()) (xx ()))
+							     (let ((res ())
+								   (f ())
+								   (j ())
+								   (xx ()))
 								  (r-block (<-
   xx (r-call r-index x 1))
-  (if (r-call is.na xx)
-      (r-block (<- j 1) (while (&& (r-call is.na xx)
-				   (r-call <= (<- j (r-call + j 1))
-					   (r-call length x)))
-			       (<- xx (r-call r-index x j)))
-	       (if (r-call is.na xx)
-		   (<- f "%Y-%m-%d"))))
+  (if (r-call is.na xx) (r-block (<- j 1)
+				 (while (&& (r-call is.na xx)
+					    (r-call <= (<- j (r-call + j 1))
+						    (r-call length x)))
+					(<- xx (r-call r-index x j)))
+				 (if (r-call is.na xx)
+				     (<- f "%Y-%m-%d"))))
   (if (|\|\|| (r-call is.na xx) (r-call ! (r-call is.na (r-call strptime xx
 								(<- f "%Y-%m-%d %H:%M:%OS"))))
 	      (r-call ! (r-call is.na (r-call strptime xx
@@ -37,25 +43,19 @@
 	      (r-call ! (r-call is.na (r-call strptime xx
 					      (<- f "%Y/%m/%d")))))
       (r-block (<- res (r-call strptime x f))
-	       (if (r-call nchar tz)
-		   (r-block (<- res (r-call attr<- res
-					    "tzone" tz))
-			    tz))
+	       (if (r-call nchar tz) (r-block (<- res (r-call attr<- res "tzone"
+							      tz))
+					      tz))
 	       (return res)))
   (r-call stop "character string is not in a standard unambiguous format")))))
-					      (if (r-call inherits x
-							  "POSIXlt")
+					      (if (r-call inherits x "POSIXlt")
 						  (return x))
-					      (if (r-call inherits x
-							  "Date")
+					      (if (r-call inherits x "Date")
 						  (return (r-call .Internal (r-call
   Date2POSIXlt x))))
-					      (<- tzone (r-call attr x
-								"tzone"))
-					      (if (|\|\|| (r-call inherits x
-								  "date")
-							  (r-call inherits x
-								  "dates"))
+					      (<- tzone (r-call attr x "tzone"))
+					      (if (|\|\|| (r-call inherits x "date")
+							  (r-call inherits x "dates"))
 						  (<- x (r-call as.POSIXct x)))
 					      (if (r-call is.character x)
 						  (return (r-call fromchar (r-call
@@ -87,26 +87,25 @@
 						    (<- tz ""))
 					      (r-call UseMethod "as.POSIXct")))))
 	       (<- as.POSIXct.Date (lambda (x ...)
-				     (let () (r-block (r-call structure (r-call
-  * (r-call unclass x) 86400)
-							      (*named* class (r-call
+				     (let ()
+					  (r-block (r-call structure (r-call *
+  (r-call unclass x) 86400)
+							   (*named* class (r-call
   c "POSIXt" "POSIXct")))))))
 	       (<- as.POSIXct.date (lambda (x ...)
 				     (let ((x ()))
-					  (r-block (if (r-call inherits x
-							       "date")
+					  (r-block (if (r-call inherits x "date")
 						       (r-block (<- x (r-call
   * (r-call - x 3653) 86400))
 								(return (r-call
-  structure x (*named* class (r-call c "POSIXt"
-				     "POSIXct")))))
+  structure x (*named* class (r-call c "POSIXt" "POSIXct")))))
 						       (r-call stop (r-call
   gettextf "'%s' is not a \"date\" object"
   (r-call deparse (substitute x)))))))))
 	       (<- as.POSIXct.dates (lambda (x ...)
-				      (let ((x ()) (z ()))
-					   (r-block (if (r-call inherits x
-								"dates")
+				      (let ((x ())
+					    (z ()))
+					   (r-block (if (r-call inherits x "dates")
 							(r-block (<- z (r-call
   attr x "origin"))
 								 (<- x (r-call
@@ -119,13 +118,13 @@
 					   (r-call r-index z 1)
 					   (r-call r-index z 2) 0)))))
 								 (return (r-call
-  structure x (*named* class (r-call c "POSIXt"
-				     "POSIXct")))))
+  structure x (*named* class (r-call c "POSIXt" "POSIXct")))))
 							(r-call stop (r-call
   gettextf "'%s' is not a \"dates\" object"
   (r-call deparse (substitute x)))))))))
 	       (<- as.POSIXct.POSIXlt (lambda (x tz)
-					(let ((tzone ()) (tz ()))
+					(let ((tzone ())
+					      (tz ()))
 					     (r-block (when (missing tz)
 							    (<- tz ""))
 						      (<- tzone (r-call attr x
@@ -145,8 +144,7 @@
 					(let ((tz ()))
 					     (r-block (when (missing tz)
 							    (<- tz ""))
-						      (if (r-call inherits x
-								  "POSIXct")
+						      (if (r-call inherits x "POSIXct")
 							  (return x))
 						      (if (|\|\|| (r-call
 								   is.character
@@ -174,26 +172,27 @@
 								    (r-call
   deparse (substitute x))))))))
 	       (<- as.numeric.POSIXlt (lambda (x)
-					(let () (r-block (r-call as.POSIXct x)))))
+					(let ()
+					     (r-block (r-call as.POSIXct x)))))
 	       (<- format.POSIXlt (lambda (x format usetz ...)
-				    (let ((np ()) (secs ()) (times ()) (format
-  ())
-						  (usetz ()))
-					 (r-block (when (missing usetz)
-							(<- usetz *r-false*))
-						  (when (missing format)
+				    (let ((np ())
+					  (secs ())
+					  (times ())
+					  (usetz ())
+					  (format ()))
+					 (r-block (when (missing format)
 							(<- format ""))
+						  (when (missing usetz)
+							(<- usetz *r-false*))
 						  (if (r-call ! (r-call
 								 inherits x "POSIXlt"))
 						      (r-call stop "wrong class"))
-						  (if (r-call == format
-							      "")
+						  (if (r-call == format "")
 						      (r-block (<- times (r-call
   unlist (r-call r-index (r-call unclass x)
 		 (r-call : 1 3))))
 							       (<- secs (r-call
-  r-aref x (index-in-strlist sec (r-call attr x
-					 #0="names"))))
+  r-aref x (index-in-strlist sec (r-call attr x #0="names"))))
 							       (<- secs (r-call
   r-index secs (r-call ! (r-call is.na secs))))
 							       (<- np (r-call
@@ -215,11 +214,9 @@
   (r-call all (r-call == (r-call r-index times
 				 (r-call ! (r-call is.na times)))
 		      0))
-  "%Y-%m-%d"
-  (if (r-call == np 0)
-      "%Y-%m-%d %H:%M:%S"
-      (r-call paste "%Y-%m-%d %H:%M:%OS" np
-	      (*named* sep "")))))))
+  "%Y-%m-%d" (if (r-call == np 0) "%Y-%m-%d %H:%M:%S"
+		 (r-call paste "%Y-%m-%d %H:%M:%OS" np
+			 (*named* sep "")))))))
 						  (r-call .Internal (r-call
   format.POSIXlt x format usetz))))))
 	       (<- strftime format.POSIXlt)
@@ -230,21 +227,22 @@
 					    (r-call .Internal (r-call strptime
   (r-call as.character x) format tz))))))
 	       (<- format.POSIXct (lambda (x format tz usetz ...)
-				    (let ((tzone ()) (format ()) (tz ()) (usetz
-  ()))
-					 (r-block (when (missing usetz)
-							(<- usetz *r-false*))
+				    (let ((tzone ())
+					  (usetz ())
+					  (tz ())
+					  (format ()))
+					 (r-block (when (missing format)
+							(<- format ""))
 						  (when (missing tz)
 							(<- tz ""))
-						  (when (missing format)
-							(<- format ""))
+						  (when (missing usetz)
+							(<- usetz *r-false*))
 						  (if (r-call ! (r-call
 								 inherits x "POSIXct"))
 						      (r-call stop "wrong class"))
 						  (if (&& (missing tz)
 							  (r-call ! (r-call
-  is.null (<- tzone (r-call attr x
-			    "tzone")))))
+  is.null (<- tzone (r-call attr x "tzone")))))
 						      (<- tz tzone))
 						  (r-call structure (r-call
   format.POSIXlt (r-call as.POSIXlt x tz) format usetz r-dotdotdot)
@@ -251,20 +249,20 @@
 							  (*named* names (r-call
   names x)))))))
 	       (<- print.POSIXct (lambda (x ...)
-				   (let () (r-block (r-call print (r-call
-								   format x (*named*
-  usetz *r-true*)
-								   r-dotdotdot)
-							    r-dotdotdot)
-						    (r-call invisible x)))))
+				   (let ()
+					(r-block (r-call print (r-call format
+  x (*named* usetz *r-true*) r-dotdotdot)
+							 r-dotdotdot)
+						 (r-call invisible x)))))
 	       (<- print.POSIXlt (lambda (x ...)
-				   (let () (r-block (r-call print (r-call
-								   format x (*named*
-  usetz *r-true*))
-							    r-dotdotdot)
-						    (r-call invisible x)))))
+				   (let ()
+					(r-block (r-call print (r-call format
+  x (*named* usetz *r-true*))
+							 r-dotdotdot)
+						 (r-call invisible x)))))
 	       (<- summary.POSIXct (lambda (object digits ...)
-				     (let ((x ()) (digits ()))
+				     (let ((x ())
+					   (digits ()))
 					  (r-block (when (missing digits)
 							 (<- digits 15))
 						   (<- x (r-call r-index (r-call
@@ -295,35 +293,32 @@
 								    digits)
 							   r-dotdotdot)))))
 	       (<- "+.POSIXt" (lambda (e1 e2)
-				(let ((e2 ()) (e1 ()) (coerceTimeUnit ()))
+				(let ((e2 ())
+				      (e1 ())
+				      (coerceTimeUnit ()))
 				     (r-block (<- coerceTimeUnit (lambda (x)
-								   (let () (r-block
-  (switch (r-call attr x
-		  "units")
-	  (*named* secs x) (*named* mins (r-call * 60 x))
-	  (*named* hours (r-call * (r-call * 60 60) x))
-	  (*named* days (r-call * (r-call * (r-call * 60 60) 24) x))
-	  (*named* weeks (r-call * (r-call * (r-call * (r-call * 60 60) 24) 7)
-				 x)))))))
+								   (let ()
+  (r-block (switch (r-call attr x "units")
+		   (*named* secs x) (*named* mins (r-call * 60 x))
+		   (*named* hours (r-call * (r-call * 60 60) x))
+		   (*named* days (r-call * (r-call * (r-call * 60 60) 24) x))
+		   (*named* weeks (r-call * (r-call * (r-call * (r-call * 60 60)
+							      24)
+						    7)
+					  x)))))))
 					      (if (r-call == (r-call nargs) 1)
 						  (return e1))
-					      (if (&& (r-call inherits e1
-							      "POSIXt")
-						      (r-call inherits e2
-							      "POSIXt"))
+					      (if (&& (r-call inherits e1 "POSIXt")
+						      (r-call inherits e2 "POSIXt"))
 						  (r-call stop "binary + is not defined for \"POSIXt\" objects"))
-					      (if (r-call inherits e1
-							  "POSIXlt")
+					      (if (r-call inherits e1 "POSIXlt")
 						  (<- e1 (r-call as.POSIXct e1)))
-					      (if (r-call inherits e2
-							  "POSIXlt")
+					      (if (r-call inherits e2 "POSIXlt")
 						  (<- e2 (r-call as.POSIXct e2)))
-					      (if (r-call inherits e1
-							  "difftime")
+					      (if (r-call inherits e1 "difftime")
 						  (<- e1 (r-call coerceTimeUnit
 								 e1)))
-					      (if (r-call inherits e2
-							  "difftime")
+					      (if (r-call inherits e2 "difftime")
 						  (<- e2 (r-call coerceTimeUnit
 								 e2)))
 					      (r-call structure (r-call + (r-call
@@ -334,27 +329,27 @@
 						      (*named* tzone (r-call
   check_tzones e1 e2)))))))
 	       (<- "-.POSIXt" (lambda (e1 e2)
-				(let ((e2 ()) (coerceTimeUnit ()))
+				(let ((e2 ())
+				      (coerceTimeUnit ()))
 				     (r-block (<- coerceTimeUnit (lambda (x)
-								   (let () (r-block
-  (switch (r-call attr x
-		  "units")
-	  (*named* secs x) (*named* mins (r-call * 60 x))
-	  (*named* hours (r-call * (r-call * 60 60) x))
-	  (*named* days (r-call * (r-call * (r-call * 60 60) 24) x))
-	  (*named* weeks (r-call * (r-call * (r-call * (r-call * 60 60) 24) 7)
-				 x)))))))
+								   (let ()
+  (r-block (switch (r-call attr x "units")
+		   (*named* secs x) (*named* mins (r-call * 60 x))
+		   (*named* hours (r-call * (r-call * 60 60) x))
+		   (*named* days (r-call * (r-call * (r-call * 60 60) 24) x))
+		   (*named* weeks (r-call * (r-call * (r-call * (r-call * 60 60)
+							      24)
+						    7)
+					  x)))))))
 					      (if (r-call ! (r-call inherits e1
 								    "POSIXt"))
 						  (r-call stop "Can only subtract from POSIXt objects"))
 					      (if (r-call == (r-call nargs) 1)
 						  (r-call stop "unary - is not defined for \"POSIXt\" objects"))
-					      (if (r-call inherits e2
-							  "POSIXt")
+					      (if (r-call inherits e2 "POSIXt")
 						  (return (r-call difftime e1
 								  e2)))
-					      (if (r-call inherits e2
-							  "difftime")
+					      (if (r-call inherits e2 "difftime")
 						  (<- e2 (r-call unclass (r-call
   coerceTimeUnit e2))))
 					      (if (r-call ! (r-call is.null (r-call
@@ -366,7 +361,9 @@
 						      (*named* class (r-call c
   "POSIXt" "POSIXct")))))))
 	       (<- Ops.POSIXt (lambda (e1 e2)
-				(let ((e2 ()) (e1 ()) (boolean ()))
+				(let ((e2 ())
+				      (e1 ())
+				      (boolean ()))
 				     (r-block (if (r-call == (r-call nargs) 1)
 						  (r-call stop "unary" .Generic
 							  " not defined for \"POSIXt\" objects"))
@@ -406,11 +403,8 @@
 				       (r-block (<- tzs (r-call unique (r-call
   sapply (r-call list r-dotdotdot) (lambda (x)
 				     (let ((y ()))
-					  (r-block (<- y (r-call attr x
-								 "tzone"))
-						   (if (r-call is.null y)
-						       ""
-						       y)))))))
+					  (r-block (<- y (r-call attr x "tzone"))
+						   (if (r-call is.null y) "" y)))))))
 						(<- tzs (r-call r-index tzs
 								(r-call != tzs
   "")))
@@ -422,7 +416,10 @@
 						    (r-call r-index tzs 1)
 						    ())))))
 	       (<- Summary.POSIXct (lambda (... na.rm)
-				     (let ((val ()) (tz ()) (args ()) (ok ()))
+				     (let ((val ())
+					   (tz ())
+					   (args ())
+					   (ok ()))
 					  (r-block (<- ok (switch .Generic (*named*
   max *r-missing*)
 								  (*named* min
@@ -450,7 +447,10 @@
 							    tz)
 						   val))))
 	       (<- Summary.POSIXlt (lambda (... na.rm)
-				     (let ((val ()) (tz ()) (args ()) (ok ()))
+				     (let ((val ())
+					   (tz ())
+					   (args ())
+					   (ok ()))
 					  (r-block (<- ok (switch .Generic (*named*
   max *r-missing*)
 								  (*named* min
@@ -472,11 +472,13 @@
 								   .Generic (r-call
   c args (*named* na.rm na.rm))))
 						   (r-call as.POSIXlt (r-call
-  structure val (*named* class (r-call c "POSIXt"
-				       "POSIXct"))
+  structure val (*named* class (r-call c "POSIXt" "POSIXct"))
   (*named* tzone tz)))))))
 	       (<- "[.POSIXct" (lambda (x ... drop)
-				 (let ((val ()) (x ()) (cl ()) (drop ()))
+				 (let ((val ())
+				       (x ())
+				       (cl ())
+				       (drop ()))
 				      (r-block (when (missing drop)
 						     (<- drop *r-true*))
 					       (<- cl (r-call oldClass x))
@@ -494,7 +496,10 @@
 							%r:4)
 					       val))))
 	       (<- "[[.POSIXct" (lambda (x ... drop)
-				  (let ((val ()) (x ()) (cl ()) (drop ()))
+				  (let ((val ())
+					(x ())
+					(cl ())
+					(drop ()))
 				       (r-block (when (missing drop)
 						      (<- drop *r-true*))
 						(<- cl (r-call oldClass x))
@@ -513,7 +518,10 @@
 							 %r:5)
 						val))))
 	       (<- "[<-.POSIXct" (lambda (x ... value)
-				   (let ((x ()) (tz ()) (cl ()) (value ()))
+				   (let ((x ())
+					 (tz ())
+					 (cl ())
+					 (value ()))
 					(r-block (if (r-call ! (r-call
 								as.logical (r-call
   length value)))
@@ -521,10 +529,11 @@
 						 (<- value (r-call as.POSIXct
 								   value))
 						 (<- cl (r-call oldClass x))
-						 (<- tz (r-call attr x
-								"tzone"))
+						 (<- tz (r-call attr x "tzone"))
 						 (r-block (ref= %r:6 (r-block
-  (<- value (r-call class<- value ())) ()))
+  (<- value (r-call class<- value
+		    ()))
+  ()))
 							  (<- x (r-call class<-
   x %r:6))
 							  %r:6)
@@ -538,13 +547,14 @@
 							  tz)
 						 x))))
 	       (<- as.character.POSIXt (lambda (x ...)
-					 (let () (r-block (r-call format x
-								  r-dotdotdot)))))
+					 (let ()
+					      (r-block (r-call format x
+							       r-dotdotdot)))))
 	       (<- as.data.frame.POSIXct as.data.frame.vector)
 	       (<- is.na.POSIXlt (lambda (x)
-				   (let () (r-block (r-call is.na (r-call
-								   as.POSIXct
-								   x))))))
+				   (let ()
+					(r-block (r-call is.na (r-call
+								as.POSIXct x))))))
 	       (<- c.POSIXct (lambda (... recursive)
 			       (let ((recursive ()))
 				    (r-block (when (missing recursive)
@@ -567,7 +577,8 @@
 							     target current)
 						     (r-call NextMethod "all.equal")))))
 	       (<- ISOdatetime (lambda (year month day hour min sec tz)
-				 (let ((x ()) (tz ()))
+				 (let ((x ())
+				       (tz ()))
 				      (r-block (when (missing tz)
 						     (<- tz ""))
 					       (<- x (r-call paste year month
@@ -580,43 +591,50 @@
   tz))
 						       (*named* tz tz))))))
 	       (<- ISOdate (lambda (year month day hour min sec tz)
-			     (let ((hour ()) (min ()) (sec ()) (tz ()))
-				  (r-block (when (missing tz)
-						 (<- tz "GMT"))
-					   (when (missing sec)
-						 (<- sec 0))
+			     (let ((tz ())
+				   (sec ())
+				   (min ())
+				   (hour ()))
+				  (r-block (when (missing hour)
+						 (<- hour 12))
 					   (when (missing min)
 						 (<- min 0))
-					   (when (missing hour)
-						 (<- hour 12))
+					   (when (missing sec)
+						 (<- sec 0))
+					   (when (missing tz)
+						 (<- tz "GMT"))
 					   (r-call ISOdatetime year month day
 					    hour min sec tz)))))
 	       (<- as.matrix.POSIXlt (lambda (x ...)
-				       (let () (r-block (r-call as.matrix (r-call
+				       (let ()
+					    (r-block (r-call as.matrix (r-call
   as.data.frame (r-call unclass x))
-								r-dotdotdot)))))
+							     r-dotdotdot)))))
 	       (<- mean.POSIXct (lambda (x ...)
-				  (let () (r-block (r-call structure (r-call
-  mean (r-call unclass x) r-dotdotdot)
-							   (*named* class (r-call
+				  (let ()
+				       (r-block (r-call structure (r-call mean
+  (r-call unclass x) r-dotdotdot)
+							(*named* class (r-call
   c "POSIXt" "POSIXct"))
-							   (*named* tzone (r-call
+							(*named* tzone (r-call
   attr x "tzone")))))))
 	       (<- mean.POSIXlt (lambda (x ...)
-				  (let () (r-block (r-call as.POSIXlt (r-call
-  mean (r-call as.POSIXct x) r-dotdotdot))))))
+				  (let ()
+				       (r-block (r-call as.POSIXlt (r-call mean
+  (r-call as.POSIXct x) r-dotdotdot))))))
 	       (<- difftime (lambda (time1 time2 tz units)
-			      (let ((zz ()) (z ()) (time2 ()) (time1 ()) (tz ())
-					    (units ()))
-				   (r-block (when (missing units)
-						  (<- units (r-call c "auto"
-								    "secs"
-								    "mins"
-								    "hours"
-								    "days"
-								    "weeks")))
-					    (when (missing tz)
+			      (let ((zz ())
+				    (z ())
+				    (time2 ())
+				    (time1 ())
+				    (units ())
+				    (tz ()))
+				   (r-block (when (missing tz)
 						  (<- tz ""))
+					    (when (missing units)
+						  (<- units (r-call c "auto" "secs"
+								    "mins" "hours"
+								    "days" "weeks")))
 					    (<- time1 (r-call as.POSIXct time1
 							      (*named* tz tz)))
 					    (<- time2 (r-call as.POSIXct time2
@@ -625,8 +643,7 @@
 								    time1)
 							  (r-call unclass time2)))
 					    (<- units (r-call match.arg units))
-					    (if (r-call == units
-							"auto")
+					    (if (r-call == units "auto")
 						(r-block (if (r-call all (r-call
   is.na z))
 							     (<- units "secs")
@@ -633,12 +650,11 @@
 							     (r-block (<- zz (r-call
   min (r-call abs z) (*named* na.rm *r-true*)))
   (if (|\|\|| (r-call is.na zz) (r-call < zz 60))
-      (<- units "secs")
-      (if (r-call < zz 3600)
-	  (<- units "mins")
-	  (if (r-call < zz 86400)
-	      (<- units "hours")
-	      (<- units "days"))))))))
+      (<- units "secs") (if (r-call < zz 3600)
+			    (<- units "mins")
+			    (if (r-call < zz 86400)
+				(<- units "hours")
+				(<- units "days"))))))))
 					    (switch units (*named* secs (r-call
   structure z (*named* units "secs")
   (*named* class "difftime")))
@@ -673,13 +689,13 @@
 								    (*named*
   class "difftime"))))))))
 	       (<- as.difftime (lambda (tim format units)
-				 (let ((format ()) (units ()))
-				      (r-block (when (missing units)
-						     (<- units "auto"))
-					       (when (missing format)
+				 (let ((units ())
+				       (format ()))
+				      (r-block (when (missing format)
 						     (<- format "%X"))
-					       (if (r-call inherits tim
-							   "difftime")
+					       (when (missing units)
+						     (<- units "auto"))
+					       (if (r-call inherits tim "difftime")
 						   (return tim))
 					       (if (r-call is.character tim)
 						   (r-block (r-call difftime (r-call
@@ -695,9 +711,7 @@
   units "auto")
 								(r-call stop "need explicit units for numeric conversion"))
 							    (if (r-call ! (r-call
-  %in% units (r-call c "secs"
-		     "mins" "hours" "days"
-		     "weeks")))
+  %in% units (r-call c "secs" "mins" "hours" "days" "weeks")))
 								(r-call stop "invalid units specified"))
 							    (r-call structure
 								    tim (*named*
@@ -709,17 +723,17 @@
 	       (<- "units<-" (lambda (x value)
 			       (let () (r-block (r-call UseMethod "units<-")))))
 	       (<- units.difftime (lambda (x)
-				    (let () (r-block (r-call attr x
-							     "units")))))
+				    (let ()
+					 (r-block (r-call attr x "units")))))
 	       (<- "units<-.difftime" (lambda (x value)
-					(let ((newx ()) (sc ()) (from ()))
+					(let ((newx ())
+					      (sc ())
+					      (from ()))
 					     (r-block (<- from (r-call units x))
 						      (if (r-call == from value)
 							  (return x))
 						      (if (r-call ! (r-call
-  %in% value (r-call c "secs"
-		     "mins" "hours" "days"
-		     "weeks")))
+  %in% value (r-call c "secs" "mins" "hours" "days" "weeks")))
 							  (r-call stop "invalid units specified"))
 						      (<- sc (r-call cumprod (r-call
   c (*named* secs 1) (*named* mins 60)
@@ -732,11 +746,11 @@
   value)
 							      (*named* class "difftime"))))))
 	       (<- as.double.difftime (lambda (x units ...)
-					(let ((x ()) (units ()))
+					(let ((x ())
+					      (units ()))
 					     (r-block (when (missing units)
 							    (<- units "auto"))
-						      (if (r-call != units
-								  "auto")
+						      (if (r-call != units "auto")
 							  (r-block (<- x (r-call
   units<- x units))
 								   units))
@@ -745,11 +759,13 @@
 	       (<- as.data.frame.difftime
 		   as.data.frame.vector)
 	       (<- format.difftime (lambda (x ...)
-				     (let () (r-block (r-call paste (r-call
-  format (r-call unclass x) r-dotdotdot)
-							      (r-call units x))))))
+				     (let ()
+					  (r-block (r-call paste (r-call format
+  (r-call unclass x) r-dotdotdot)
+							   (r-call units x))))))
 	       (<- print.difftime (lambda (x digits ...)
-				    (let ((y ()) (digits ()))
+				    (let ((y ())
+					  (digits ()))
 					 (r-block (when (missing digits)
 							(<- digits (r-call
 								    getOption
@@ -760,14 +776,12 @@
   length x)
   1))
 						      (r-block (r-call cat "Time differences in "
-  (r-call attr x
-	  "units")
-  "\n" (*named* sep ""))
+  (r-call attr x "units") "\n" (*named* sep ""))
 							       (<- y (r-call
   unclass x))
 							       (r-block (<- y
-  (r-call attr<- y
-	  "units" ()))
+  (r-call attr<- y "units"
+	  ()))
   ())
 							       (r-call print y))
 						      (r-call cat "Time difference of "
@@ -774,24 +788,26 @@
 							      (r-call format (r-call
   unclass x)
   (*named* digits digits))
-							      " "
-							      (r-call attr x
-  "units")
-							      "\n"
-							      (*named* sep "")))
+							      " " (r-call attr
+  x "units")
+							      "\n" (*named* sep
+  "")))
 						  (r-call invisible x)))))
 	       (<- round.difftime (lambda (x digits ...)
-				    (let ((units ()) (digits ()))
+				    (let ((units ())
+					  (digits ()))
 					 (r-block (when (missing digits)
 							(<- digits 0))
-						  (<- units (r-call attr x
-								    "units"))
+						  (<- units (r-call attr x "units"))
 						  (r-call structure (r-call
   NextMethod)
 							  (*named* units units)
 							  (*named* class "difftime"))))))
 	       (<- "[.difftime" (lambda (x ... drop)
-				  (let ((val ()) (x ()) (cl ()) (drop ()))
+				  (let ((val ())
+					(x ())
+					(cl ())
+					(drop ()))
 				       (r-block (when (missing drop)
 						      (<- drop *r-true*))
 						(<- cl (r-call oldClass x))
@@ -810,11 +826,13 @@
 							 %r:7)
 						val))))
 	       (<- Ops.difftime (lambda (e1 e2)
-				  (let ((u1 ()) (e2 ()) (boolean ()) (e1 ()) (coerceTimeUnit
-  ()))
+				  (let ((u1 ())
+					(e2 ())
+					(boolean ())
+					(e1 ())
+					(coerceTimeUnit ()))
 				       (r-block (<- coerceTimeUnit (lambda (x)
-  (let () (r-block (switch (r-call attr x
-				   "units")
+  (let () (r-block (switch (r-call attr x "units")
 			   (*named* secs x)
 			   (*named* mins (r-call * 60 x))
 			   (*named* hours (r-call * (r-call * 60 60) x))
@@ -852,16 +870,12 @@
 								    (*named* >=
   *r-true*)
 								    *r-false*))
-						(if boolean
-						    (r-block (if (&& (r-call
+						(if boolean (r-block (if (&& (r-call
   inherits e1 "difftime")
-  (r-call inherits e2
-	  "difftime"))
-								 (r-block (<-
-  e1 (r-call coerceTimeUnit e1))
-  (<- e2 (r-call coerceTimeUnit e2))))
-							     (r-call NextMethod
-  .Generic))
+  (r-call inherits e2 "difftime"))
+  (r-block (<- e1 (r-call coerceTimeUnit e1))
+	   (<- e2 (r-call coerceTimeUnit e2))))
+  (r-call NextMethod .Generic))
 						    (if (|\|\|| (r-call ==
   .Generic "+")
 								(r-call ==
@@ -868,27 +882,20 @@
   .Generic "-"))
 							(r-block (if (&& (r-call
   inherits e1 "difftime")
-  (r-call ! (r-call inherits e2
-		    "difftime")))
+  (r-call ! (r-call inherits e2 "difftime")))
   (return (r-call structure (r-call NextMethod .Generic)
-		  (*named* units (r-call attr e1
-					 "units"))
+		  (*named* units (r-call attr e1 "units"))
 		  (*named* class "difftime"))))
 								 (if (&& (r-call
-  ! (r-call inherits e1
-	    "difftime"))
-  (r-call inherits e2
-	  "difftime"))
+  ! (r-call inherits e1 "difftime"))
+  (r-call inherits e2 "difftime"))
   (return (r-call structure (r-call NextMethod .Generic)
-		  (*named* units (r-call attr e2
-					 "units"))
+		  (*named* units (r-call attr e2 "units"))
 		  (*named* class "difftime"))))
 								 (<- u1 (r-call
   attr e1 "units"))
 								 (if (r-call ==
-  (r-call attr e2
-	  "units")
-  u1)
+  (r-call attr e2 "units") u1)
   (r-block (r-call structure (r-call NextMethod .Generic)
 		   (*named* units u1) (*named* class "difftime")))
   (r-block (<- e1 (r-call coerceTimeUnit e1))
@@ -899,14 +906,13 @@
 							(r-block (r-call stop
   .Generic "not defined for \"difftime\" objects"))))))))
 	       (<- "*.difftime" (lambda (e1 e2)
-				  (let ((e2 ()) (e1 ()) (tmp ()))
-				       (r-block (if (&& (r-call inherits e1
-								"difftime")
-							(r-call inherits e2
-								"difftime"))
+				  (let ((e2 ())
+					(e1 ())
+					(tmp ()))
+				       (r-block (if (&& (r-call inherits e1 "difftime")
+							(r-call inherits e2 "difftime"))
 						    (r-call stop "both arguments of * cannot be \"difftime\" objects"))
-						(if (r-call inherits e2
-							    "difftime")
+						(if (r-call inherits e2 "difftime")
 						    (r-block (<- tmp e1)
 							     (<- e1 e2)
 							     (<- e2 tmp)))
@@ -916,25 +922,27 @@
   attr e1 "units"))
 							(*named* class "difftime"))))))
 	       (<- "/.difftime" (lambda (e1 e2)
-				  (let () (r-block (if (r-call inherits e2
-							       "difftime")
-						       (r-call stop "second argument of / cannot be a \"difftime\" object"))
-						   (r-call structure (r-call /
-  (r-call unclass e1) e2)
-							   (*named* units (r-call
+				  (let ()
+				       (r-block (if (r-call inherits e2 "difftime")
+						    (r-call stop "second argument of / cannot be a \"difftime\" object"))
+						(r-call structure (r-call / (r-call
+  unclass e1)
+  e2)
+							(*named* units (r-call
   attr e1 "units"))
-							   (*named* class "difftime"))))))
+							(*named* class "difftime"))))))
 	       (<- Math.difftime (lambda (x ...)
-				   (let () (r-block (r-call stop .Generic
-							    "not defined for \"difftime\" objects")))))
+				   (let ()
+					(r-block (r-call stop .Generic
+							 "not defined for \"difftime\" objects")))))
 	       (<- mean.difftime (lambda (x ... na.rm)
-				   (let ((args ()) (coerceTimeUnit ()) (na.rm
-  ()))
+				   (let ((args ())
+					 (coerceTimeUnit ())
+					 (na.rm ()))
 					(r-block (when (missing na.rm)
 						       (<- na.rm *r-false*))
 						 (<- coerceTimeUnit (lambda (x)
-  (let () (r-block (r-call as.vector (switch (r-call attr x
-						     "units")
+  (let () (r-block (r-call as.vector (switch (r-call attr x "units")
 					     (*named* secs x)
 					     (*named* mins (r-call * 60 x))
 					     (*named* hours (r-call * (r-call
@@ -957,15 +965,14 @@
 						     (r-block (r-call structure
   (r-call mean (r-call as.vector x)
 	  (*named* na.rm na.rm))
-  (*named* units (r-call attr x
-			 "units"))
+  (*named* units (r-call attr x "units"))
   (*named* class "difftime"))))))))
 	       (<- Summary.difftime (lambda (... na.rm)
-				      (let ((args ()) (ok ()) (coerceTimeUnit
-							       ()))
+				      (let ((args ())
+					    (ok ())
+					    (coerceTimeUnit ()))
 					   (r-block (<- coerceTimeUnit (lambda (x)
-  (let () (r-block (r-call as.vector (switch (r-call attr x
-						     "units")
+  (let () (r-block (r-call as.vector (switch (r-call attr x "units")
 					     (*named* secs x)
 					     (*named* mins (r-call * 60 x))
 					     (*named* hours (r-call * (r-call
@@ -996,15 +1003,24 @@
 							    (*named* units "secs")
 							    (*named* class "difftime"))))))
 	       (<- seq.POSIXt (lambda (from to by length.out along.with ...)
-				(let ((mon ()) (yr ()) (r1 ()) (by2 ()) (by ())
-				      (valid ()) (res ()) (to ()) (from ()) (status
-  ())
-				      (tz ()) (cfrom ()) (length.out ()) (along.with
-  ()))
-				     (r-block (when (missing along.with)
-						    (<- along.with ()))
-					      (when (missing length.out)
+				(let ((mon ())
+				      (yr ())
+				      (r1 ())
+				      (by2 ())
+				      (by ())
+				      (valid ())
+				      (res ())
+				      (to ())
+				      (from ())
+				      (status ())
+				      (tz ())
+				      (cfrom ())
+				      (along.with ())
+				      (length.out ()))
+				     (r-block (when (missing length.out)
 						    (<- length.out ()))
+					      (when (missing along.with)
+						    (<- along.with ()))
 					      (if (missing from)
 						  (r-call stop "'from' must be specified"))
 					      (if (r-call ! (r-call inherits
@@ -1015,8 +1031,7 @@
   cfrom)
 							  1)
 						  (r-call stop "'from' must be of length 1"))
-					      (<- tz (r-call attr cfrom
-							     "tzone"))
+					      (<- tz (r-call attr cfrom "tzone"))
 					      (if (r-call ! (missing to))
 						  (r-block (if (r-call ! (r-call
   inherits to "POSIXt"))
@@ -1060,8 +1075,7 @@
 							   (return (r-call
 								    structure
 								    res (*named*
-  class (r-call c "POSIXt"
-		"POSIXct"))
+  class (r-call c "POSIXt" "POSIXct"))
 								    (*named*
   tzone tz)))))
 					      (if (r-call != (r-call length by)
@@ -1068,18 +1082,16 @@
 							  1)
 						  (r-call stop "'by' must be of length 1"))
 					      (<- valid 0)
-					      (if (r-call inherits by
-							  "difftime")
+					      (if (r-call inherits by "difftime")
 						  (r-block (<- by (r-call * (switch
-  (r-call attr by
-	  "units")
-  (*named* secs 1) (*named* mins 60) (*named* hours 3600)
-  (*named* days 86400) (*named* weeks (r-call * 7 86400)))
+  (r-call attr by "units") (*named* secs 1)
+  (*named* mins 60) (*named* hours 3600) (*named* days 86400)
+  (*named* weeks (r-call * 7 86400)))
   (r-call unclass by))))
 						  (if (r-call is.character by)
 						      (r-block (<- by2 (r-call
-  r-aref (r-call strsplit by
-		 " " (*named* fixed *r-true*))
+  r-aref (r-call strsplit by " "
+		 (*named* fixed *r-true*))
   1))
 							       (if (|\|\|| (r-call
   > (r-call length by2) 2)
@@ -1089,10 +1101,7 @@
 							       (<- valid (r-call
   pmatch (r-call r-index by2
 		 (r-call length by2))
-  (r-call c "secs"
-	  "mins" "hours" "days"
-	  "weeks" "months" "years"
-	  "DSTdays")))
+  (r-call c "secs" "mins" "hours" "days" "weeks" "months" "years" "DSTdays")))
 							       (if (r-call
 								    is.na valid)
 								   (r-call stop
@@ -1103,12 +1112,11 @@
   by (r-call r-index (r-call c 1 60 3600 86400
 			     (r-call * 7 86400))
 	     valid))
-  (if (r-call == (r-call length by2) 2)
-      (<- by (r-call * by
-		     (r-call as.integer (r-call r-index by2 1))))))
+  (if (r-call == (r-call length by2) 2) (<- by (r-call * by
+						       (r-call as.integer (r-call
+  r-index by2 1))))))
 								   (<- by (if
-  (r-call == (r-call length by2) 2)
-  (r-call as.integer (r-call r-index by2 1))
+  (r-call == (r-call length by2) 2) (r-call as.integer (r-call r-index by2 1))
   1))))
 						      (if (r-call ! (r-call
   is.numeric by))
@@ -1131,8 +1139,7 @@
 							   (return (r-call
 								    structure
 								    res (*named*
-  class (r-call c "POSIXt"
-		"POSIXct"))
+  class (r-call c "POSIXt" "POSIXct"))
 								    (*named*
   tzone tz))))
 						  (r-block (<- r1 (r-call
@@ -1152,13 +1159,10 @@
 					  (index-in-strlist year (r-call attr
   r1 #0#)))
 			  (r-call r-aref to
-				  (index-in-strlist year (r-call attr to
-								 #0#)))
+				  (index-in-strlist year (r-call attr to #0#)))
 			  by))))
   (r-block (<- r1 (r-call r-aref<- r1
-			  (index-in-strlist year (r-call attr r1
-							 #0#))
-			  yr))
+			  (index-in-strlist year (r-call attr r1 #0#)) yr))
 	   yr)
   (r-block (ref= %r:9 (r-call - 1)) (<- r1 (r-call r-aref<- r1
 						   (index-in-strlist isdst (r-call
@@ -1169,12 +1173,11 @@
 							       (if (r-call ==
   valid 6)
 								   (r-block (if
-  (missing to)
-  (r-block (<- mon (r-call seq.int (r-call r-aref r1
-					   (index-in-strlist mon (r-call attr
-  r1 #0#)))
-			   (*named* by by)
-			   (*named* length length.out))))
+  (missing to) (r-block (<- mon (r-call seq.int (r-call r-aref r1
+							(index-in-strlist mon
+  (r-call attr r1 #0#)))
+					(*named* by by)
+					(*named* length length.out))))
   (r-block (<- to (r-call as.POSIXlt to))
 	   (<- mon (r-call seq.int (r-call r-aref r1
 					   (index-in-strlist mon (r-call attr
@@ -1193,9 +1196,7 @@
   to #0#))))
 			   by))))
   (r-block (<- r1 (r-call r-aref<- r1
-			  (index-in-strlist mon (r-call attr r1
-							#0#))
-			  mon))
+			  (index-in-strlist mon (r-call attr r1 #0#)) mon))
 	   mon)
   (r-block (ref= %r:10 (r-call - 1)) (<- r1 (r-call r-aref<- r1
 						    (index-in-strlist isdst (r-call
@@ -1205,54 +1206,55 @@
   (<- res (r-call as.POSIXct r1)))
 								   (if (r-call
   == valid 8)
-  (r-block (if (r-call ! (missing to))
-	       (r-block (<- length.out (r-call + 2
-					       (r-call floor (r-call / (r-call
-  - (r-call unclass (r-call as.POSIXct to))
-  (r-call unclass (r-call as.POSIXct from)))
-  86400))))))
+  (r-block (if (r-call ! (missing to)) (r-block (<- length.out (r-call + 2
+  (r-call floor (r-call / (r-call - (r-call unclass (r-call as.POSIXct to))
+				  (r-call unclass (r-call as.POSIXct from)))
+			86400))))))
 	   (r-block (ref= %r:11 (r-call seq.int (r-call r-aref r1
 							(index-in-strlist mday
-  (r-call attr r1
-	  #0#)))
+  (r-call attr r1 #0#)))
 					(*named* by by)
 					(*named* length length.out)))
 		    (<- r1 (r-call r-aref<- r1
-				   (index-in-strlist mday (r-call attr r1
-								  #0#))
+				   (index-in-strlist mday (r-call attr r1 #0#))
 				   %r:11))
 		    %r:11)
 	   (r-block (ref= %r:12 (r-call - 1))
 		    (<- r1 (r-call r-aref<- r1
-				   (index-in-strlist isdst (r-call attr r1
-								   #0#))
+				   (index-in-strlist isdst (r-call attr r1 #0#))
 				   %r:12))
 		    %r:12)
 	   (<- res (r-call as.POSIXct r1))
-	   (if (r-call ! (missing to))
-	       (<- res (r-call r-index res
-			       (r-call <= res
-				       (r-call as.POSIXct to)))))))))
+	   (if (r-call ! (missing to)) (<- res (r-call r-index res
+						       (r-call <= res
+							       (r-call
+								as.POSIXct to)))))))))
 							   (return res)))))))
 	       (<- cut.POSIXt (lambda (x breaks labels start.on.monday right
 					 ...)
-				(let ((res ()) (maxx ()) (incr ()) (start ())
-				      (valid ()) (by2 ()) (breaks ()) (x ()) (labels
-  ())
-				      (start.on.monday ()) (right ()))
-				     (r-block (when (missing right)
-						    (<- right *r-false*))
+				(let ((res ())
+				      (maxx ())
+				      (incr ())
+				      (start ())
+				      (valid ())
+				      (by2 ())
+				      (breaks ())
+				      (x ())
+				      (right ())
+				      (start.on.monday ())
+				      (labels ()))
+				     (r-block (when (missing labels)
+						    (<- labels ()))
 					      (when (missing start.on.monday)
 						    (<- start.on.monday
 							*r-true*))
-					      (when (missing labels)
-						    (<- labels ()))
+					      (when (missing right)
+						    (<- right *r-false*))
 					      (if (r-call ! (r-call inherits x
 								    "POSIXt"))
 						  (r-call stop "'x' must be a date-time object"))
 					      (<- x (r-call as.POSIXct x))
-					      (if (r-call inherits breaks
-							  "POSIXt")
+					      (if (r-call inherits breaks "POSIXt")
 						  (r-block (<- breaks (r-call
   as.POSIXct breaks)))
 						  (if (&& (r-call is.numeric
@@ -1268,8 +1270,8 @@
   length breaks)
   1))
 							  (r-block (<- by2 (r-call
-  r-aref (r-call strsplit breaks
-		 " " (*named* fixed *r-true*))
+  r-aref (r-call strsplit breaks " "
+		 (*named* fixed *r-true*))
   1))
 								   (if (|\|\||
   (r-call > (r-call length by2) 2) (r-call < (r-call length by2) 1))
@@ -1277,10 +1279,7 @@
 								   (<- valid (r-call
   pmatch (r-call r-index by2
 		 (r-call length by2))
-  (r-call c "secs"
-	  "mins" "hours" "days"
-	  "weeks" "months" "years"
-	  "DSTdays")))
+  (r-call c "secs" "mins" "hours" "days" "weeks" "months" "years" "DSTdays")))
 								   (if (r-call
   is.na valid)
   (r-call stop "invalid specification of 'breaks'"))
@@ -1325,20 +1324,20 @@
   #0#))
 				      %r:13))
 		    %r:13)
-	   (if start.on.monday
-	       (r-block (ref= %r:14 (r-call + (r-call r-aref start
-						      (index-in-strlist mday (r-call
-  attr start #0#)))
-					    (r-call ifelse (r-call > (r-call
-  r-aref start (index-in-strlist wday (r-call attr start
-					      #0#)))
-								   0)
-						    1 (r-call - 6))))
-			(<- start (r-call r-aref<- start
-					  (index-in-strlist mday (r-call attr
+	   (if start.on.monday (r-block (ref= %r:14 (r-call + (r-call r-aref
+  start (index-in-strlist mday (r-call attr start #0#)))
+							    (r-call ifelse (r-call
+  > (r-call r-aref start
+	    (index-in-strlist wday (r-call attr start #0#)))
+  0)
+								    1 (r-call
+  - 6))))
+					(<- start (r-call r-aref<- start
+							  (index-in-strlist
+							   mday (r-call attr
   start #0#))
-					  %r:14))
-			%r:14))
+							  %r:14))
+					%r:14))
 	   (<- incr (r-call * 7 86400))))
 								   (if (r-call
   == valid 6)
@@ -1400,7 +1399,8 @@
 	       (<- julian (lambda (x ...)
 			    (let () (r-block (r-call UseMethod "julian")))))
 	       (<- julian.POSIXt (lambda (x origin ...)
-				   (let ((res ()) (origin ()))
+				   (let ((res ())
+					 (origin ()))
 					(r-block (when (missing origin)
 						       (<- origin (r-call
 								   as.POSIXct
@@ -1427,8 +1427,7 @@
 						   (r-call format x
 							   (r-call ifelse
 								   abbreviate
-								   "%a"
-								   "%A"))))))
+								   "%a" "%A"))))))
 	       (<- months (lambda (x abbreviate)
 			    (let () (r-block (r-call UseMethod "months")))))
 	       (<- months.POSIXt (lambda (x abbreviate)
@@ -1452,7 +1451,8 @@
 							   (r-call + x 1)
 							   (*named* sep ""))))))
 	       (<- trunc.POSIXt (lambda (x units)
-				  (let ((x ()) (units ()))
+				  (let ((x ())
+					(units ()))
 				       (r-block (when (missing units)
 						      (<- units (r-call c "secs"
   "mins" "hours" "days")))
@@ -1460,8 +1460,7 @@
 								  units))
 						(<- x (r-call as.POSIXlt x))
 						(if (r-call > (r-call length (r-call
-  r-aref x (index-in-strlist sec (r-call attr x
-					 #0#))))
+  r-aref x (index-in-strlist sec (r-call attr x #0#))))
 							    0)
 						    (switch units (*named* secs
   (r-block (r-block (ref= %r:16 (r-call trunc (r-call r-aref x
@@ -1468,42 +1467,29 @@
 						      (index-in-strlist sec (r-call
   attr x #0#)))))
 		    (<- x (r-call r-aref<- x
-				  (index-in-strlist sec (r-call attr x
-								#0#))
+				  (index-in-strlist sec (r-call attr x #0#))
 				  %r:16))
 		    %r:16)))
 							    (*named* mins (r-block
   (r-block (<- x (r-call r-aref<- x
-			 (index-in-strlist sec (r-call attr x
-						       #0#))
-			 0))
+			 (index-in-strlist sec (r-call attr x #0#)) 0))
 	   0)))
 							    (*named* hours (r-block
   (r-block (<- x (r-call r-aref<- x
-			 (index-in-strlist sec (r-call attr x
-						       #0#))
-			 0))
+			 (index-in-strlist sec (r-call attr x #0#)) 0))
 	   0)
   (r-block (<- x (r-call r-aref<- x
-			 (index-in-strlist min (r-call attr x
-						       #0#))
-			 0))
+			 (index-in-strlist min (r-call attr x #0#)) 0))
 	   0)))
 							    (*named* days (r-block
   (r-block (<- x (r-call r-aref<- x
-			 (index-in-strlist sec (r-call attr x
-						       #0#))
-			 0))
+			 (index-in-strlist sec (r-call attr x #0#)) 0))
 	   0)
   (r-block (<- x (r-call r-aref<- x
-			 (index-in-strlist min (r-call attr x
-						       #0#))
-			 0))
+			 (index-in-strlist min (r-call attr x #0#)) 0))
 	   0)
   (r-block (<- x (r-call r-aref<- x
-			 (index-in-strlist hour (r-call attr x
-							#0#))
-			 0))
+			 (index-in-strlist hour (r-call attr x #0#)) 0))
 	   0)
   (r-block (ref= %r:17 (r-call - 1)) (<- x (r-call r-aref<- x
 						   (index-in-strlist isdst (r-call
@@ -1512,7 +1498,8 @@
 	   %r:17)))))
 						x))))
 	       (<- round.POSIXt (lambda (x units)
-				  (let ((x ()) (units ()))
+				  (let ((x ())
+					(units ()))
 				       (r-block (when (missing units)
 						      (<- units (r-call c "secs"
   "mins" "hours" "days")))
@@ -1530,13 +1517,13 @@
 						(r-call trunc.POSIXt x
 							(*named* units units))))))
 	       (<- "[.POSIXlt" (lambda (x ... drop)
-				 (let ((val ()) (drop ()))
+				 (let ((val ())
+				       (drop ()))
 				      (r-block (when (missing drop)
 						     (<- drop *r-true*))
-					       (<- val (r-call lapply x
-							       "[" r-dotdotdot
-							       (*named* drop
-  drop)))
+					       (<- val (r-call lapply x "["
+							       r-dotdotdot (*named*
+  drop drop)))
 					       (r-block (ref= %r:18 (r-call
   attributes x))
 							(<- val (r-call
@@ -1545,7 +1532,9 @@
 							%r:18)
 					       val))))
 	       (<- "[<-.POSIXlt" (lambda (x i value)
-				   (let ((x ()) (cl ()) (value ()))
+				   (let ((x ())
+					 (cl ())
+					 (value ()))
 					(r-block (if (r-call ! (r-call
 								as.logical (r-call
   length value)))
@@ -1554,7 +1543,9 @@
 								   value))
 						 (<- cl (r-call oldClass x))
 						 (r-block (ref= %r:19 (r-block
-  (<- value (r-call class<- value ())) ()))
+  (<- value (r-call class<- value
+		    ()))
+  ()))
 							  (<- x (r-call class<-
   x %r:19))
 							  %r:19)
@@ -1570,15 +1561,16 @@
 							  cl)
 						 x))))
 	       (<- as.data.frame.POSIXlt (lambda (x row.names optional ...)
-					   (let ((value ()) (row.names ()) (optional
-  ()))
+					   (let ((value ())
+						 (optional ())
+						 (row.names ()))
 						(r-block (when (missing
+								row.names)
+							       (<- row.names ()))
+							 (when (missing
 								optional)
 							       (<- optional
 								   *r-false*))
-							 (when (missing
-								row.names)
-							       (<- row.names ()))
 							 (<- value (r-call
 								    as.data.frame.POSIXct
 								    (r-call
@@ -1611,22 +1603,24 @@
 							%r:23)
 					       y))))
 	       (<- diff.POSIXt (lambda (x lag differences ...)
-				 (let ((i1 ()) (xlen ()) (r ()) (ismat ()) (lag
-  ())
-					       (differences ()))
-				      (r-block (when (missing differences)
-						     (<- differences 1))
-					       (when (missing lag)
+				 (let ((i1 ())
+				       (xlen ())
+				       (r ())
+				       (ismat ())
+				       (differences ())
+				       (lag ()))
+				      (r-block (when (missing lag)
 						     (<- lag 1))
+					       (when (missing differences)
+						     (<- differences 1))
 					       (<- ismat (r-call is.matrix x))
-					       (<- r (if (r-call inherits x
-								 "POSIXlt")
+					       (<- r (if (r-call inherits x "POSIXlt")
 							 (r-call as.POSIXct x)
 							 x))
-					       (<- xlen (if ismat
-							    (r-call r-index (r-call
+					       (<- xlen (if ismat (r-call
+								   r-index (r-call
   dim x)
-								    1)
+								   1)
 							    (r-call length r)))
 					       (if (|\|\|| (r-call > (r-call
   length lag)
@@ -1650,20 +1644,15 @@
 								    units "secs"))))
 					       (<- i1 (r-call : (r-call - 1)
 							      (r-call - lag)))
-					       (if ismat
-						   (for i (r-call : 1
-								  differences)
-						     (<- r (r-call - (r-call
+					       (if ismat (for i (r-call : 1
+  differences)
+							   (<- r (r-call - (r-call
   r-index r i1 *r-missing*
   (*named* drop *r-false*))
-								   (r-call
-								    r-index r
-								    (r-call :
-  (r-call - (r-call nrow r)) (r-call - (r-call + (r-call - (r-call nrow r) lag)
-					       1)))
-								    *r-missing*
-								    (*named*
-  drop *r-false*)))))
+  (r-call r-index r
+	  (r-call : (r-call - (r-call nrow r))
+		  (r-call - (r-call + (r-call - (r-call nrow r) lag) 1)))
+	  *r-missing* (*named* drop *r-false*)))))
 						   (for i (r-call : 1
 								  differences)
 						     (<- r (r-call - (r-call
@@ -1676,7 +1665,8 @@
 						 1))))))))
 					       r))))
 	       (<- duplicated.POSIXlt (lambda (x incomparables ...)
-					(let ((x ()) (incomparables ()))
+					(let ((x ())
+					      (incomparables ()))
 					     (r-block (when (missing
 							     incomparables)
 							    (<- incomparables
@@ -1694,11 +1684,12 @@
 							  (r-call ! (r-call
   duplicated x incomparables r-dotdotdot)))))))
 	       (<- sort.POSIXlt (lambda (x decreasing na.last ...)
-				  (let ((decreasing ()) (na.last ()))
-				       (r-block (when (missing na.last)
-						      (<- na.last NA))
-						(when (missing decreasing)
+				  (let ((na.last ())
+					(decreasing ()))
+				       (r-block (when (missing decreasing)
 						      (<- decreasing *r-false*))
+						(when (missing na.last)
+						      (<- na.last NA))
 						(r-call r-index x
 							(r-call order (r-call
   as.POSIXct x)
--- a/femtolisp/compiler.lsp
+++ b/femtolisp/compiler.lsp
@@ -26,6 +26,7 @@
 	  :add2 :sub2 :neg :largc :lvargc
 	  :loada0 :loada1 :loadc00 :loadc01 :call.l :tcall.l
 	  :brne :brne.l :cadr :brnn :brnn.l :brn :brn.l
+	  :optargs
 	  
 	  dummy_t dummy_f dummy_nil]))
     (for 0 (1- (length keys))
@@ -171,7 +172,7 @@
 		      ((number? nxt)
 		       (case vi
 			 ((:loadv.l :loadg.l :setg.l :loada.l :seta.l
-			   :largc :lvargc :call.l :tcall.l)
+			   :largc :lvargc :call.l :tcall.l :optargs)
 			  (io.write bcode (int32 nxt))
 			  (set! i (+ i 1)))
 			 
@@ -346,6 +347,7 @@
     (if (and (pair? head)
 	     (eq? (car head) 'lambda)
 	     (list? (cadr head))
+	     (every symbol? (cadr head))
 	     (not (length> (cadr head) 255)))
 	(compile-let  g env tail? x)
 	(compile-call g env tail? x))))
@@ -505,6 +507,28 @@
 		    (else ())))))
     (lambda (expr) (delete-duplicates (get-defined-vars- expr)))))
 
+(define (lambda-vars l)
+  (define (check-formals l o)
+    (or
+     (null? l) (symbol? l)
+     (and
+      (pair? l)
+      (or (symbol? (car l))
+	  (and (pair? (car l))
+	       (or (every pair? (cdr l))
+		   (error (string "compile error: invalid argument list "
+				  o ". optional arguments must come last."))))
+	  (error (string "compile error: invalid formal argument " (car l)
+			 " in list " o)))
+      (check-formals (cdr l) o))
+     (if (eq? l o)
+	 (error (string "compile error: invalid argument list " o))
+	 (error (string "compile error: invalid formal argument " l
+			" in list " o)))))
+  (check-formals l l)
+  (map (lambda (s) (if (pair? s) (car s) s))
+       (to-proper l)))
+
 (define compile-f-
   (let ((*defines-processed-token* (gensym)))
     ; to eval a top-level expression we need to avoid internal define
@@ -529,24 +553,35 @@
       
       (let ((g    (make-code-emitter))
 	    (args (cadr f))
+	    (vars (lambda-vars (cadr f)))
+	    (opta (filter pair? (cadr f)))
 	    (name (if (eq? (lastcdr f) *defines-processed-token*)
 		      'lambda
 		      (lastcdr f))))
-	(cond ((not (null? let?))      (emit g :let))
-	      ((length> args 255)      (emit g (if (null? (lastcdr args))
-						   :largc :lvargc)
-					     (length args)))
-	      ((null? (lastcdr args))  (emit g :argc  (length args)))
-	      (else  (emit g :vargc (if (atom? args) 0 (length args)))))
-	(compile-in g (cons (to-proper args) env) #t
-		    (if (eq? (lastcdr f) *defines-processed-token*)
-			(caddr f)
-			(lambda-body f)))
-	(emit g :ret)
-	(values (function (encode-byte-code (bcode:code g))
-			  (const-to-idx-vec g) name)
-		(aref g 3))))))
+	(let ((nargs (if (atom? args) 0 (length args))))
 
+	  ; emit argument checking prologue
+	  (if (not (null? opta))
+	      (begin (bcode:indexfor g (list->vector (map cadr opta)))
+		     (emit g :optargs (- nargs (length opta)))))
+
+	  (cond ((not (null? let?))      (emit g :let))
+		((> nargs 255)           (emit g (if (null? (lastcdr args))
+						     :largc :lvargc)
+					       nargs))
+		((null? (lastcdr args))  (emit g :argc  nargs))
+		(else  (emit g :vargc nargs)))
+
+	  ; compile body and return
+	  (compile-in g (cons vars env) #t
+		      (if (eq? (lastcdr f) *defines-processed-token*)
+			  (caddr f)
+			  (lambda-body f)))
+	  (emit g :ret)
+	  (values (function (encode-byte-code (bcode:code g))
+			    (const-to-idx-vec g) name)
+		  (aref g 3)))))))
+
 (define (compile f) (compile-f () f))
 
 (define (ref-int32-LE a i)
@@ -604,7 +639,7 @@
 		  (princ (number->string (aref code i)))
 		  (set! i (+ i 1)))
 		 
-		 ((:loada.l :seta.l :largc :lvargc :call.l :tcall.l)
+		 ((:loada.l :seta.l :largc :lvargc :call.l :tcall.l :optargs)
 		  (princ (number->string (ref-int32-LE code i)))
 		  (set! i (+ i 4)))
 
--- a/femtolisp/flisp.boot
+++ b/femtolisp/flisp.boot
@@ -1,1 +1,1 @@
-(zero? #function("7000r1~`W;" [] zero?) vector.map #function("8000r2c0e1\x7f31u42;" [#function("8000vc0e1~31u42;" [#function(":000v`\x80azc0qw2~;" [#function(":000r1\x80~i20i21~[31\\;" [])]) vector.alloc]) length] vector.map) vector->list #function("9000r1c0e1~31_u43;" [#function(":000va~c0qw2\x7f;" [#function("8000r1i10\x80~z[\x81Ko01;" [])]) length] vector->list) values #function("9000s0~F16602~NA650~M;\x80~K;" [] #5=[(*values*) ()]) untrace #function("8000r1c0e1~31u42;" [#function("9000ve0~316@0e1\x80e2~31b2[42;^;" [traced? set-top-level-value! function:vals]) top-level-value] untrace) traced? #function("8000r1e0~31e0\x8031>;" [function:code] [#function(":000s0e0c1~K312c2~x2;" [println x #.apply]) ()]) trace #function("8000r1c0e1~31u322c2;" [#function("8000vc0e130u42;" [#function("?000ve0\x80317a0e1i10e2c3~c4c5c6c7i10L2~L3L2c8c7\x80L2~L3L3L33142;^;" [traced? set-top-level-value! eval lambda begin println cons quote apply]) gensym]) top-level-value ok] trace) to-proper #function("9000r1~\x8740~;~?660~L1;~Me0~N31K;" [to-proper] to-proper) table.values #function("9000r1e0c1_~43;" [table.foldl #function("7000r3\x7fg2K;" [])] table.values) table.pairs #function("9000r1e0c1_~43;" [table.foldl #function("7000r3~\x7fKg2K;" [])] table.pairs) table.keys #function("9000r1e0c1_~43;" [table.foldl #function("7000r3~g2K;" [])] table.keys) table.invert #function("8000r1c0e130u42;" [#function("9000ve0c1q_\x80332~;" [table.foldl #function("9000r3e0\x80\x7f~43;" [put!])]) table] table.invert) table.foreach #function("9000r2e0c1q_\x7f43;" [table.foldl #function("8000r3\x80~\x7f322];" [])] table.foreach) table.clone #function("8000r1c0e130u42;" [#function("9000ve0c1q_\x80332~;" [table.foldl #function("9000r3e0\x80~\x7f43;" [put!])]) table] table.clone) symbol-syntax #function("9000r1e0e1~^43;" [get *syntax-environment*] symbol-syntax) string.trim #function("9000r3c0^^u43;" [#function("8000vc0qm02c1qm12c2e3\x8031u42;" [#function(";000r4g2g3X16?02e0\x7fe1~g232326A0\x80~\x7fe2~g232g344;g2;" [string.find string.char string.inc] trim-start) #function("<000r3e0g2`3216D02e1\x7fe2~e3~g23232326?0\x81~\x7fe3~g23243;g2;" [> string.find string.char string.dec] trim-end) #function("<000ve0i10\x80i10i11`~34\x81i10i12~3343;" [string.sub]) length])] string.trim) string.tail #function(";000r2e0~e1~`\x7f3342;" [string.sub string.inc] string.tail) string.rpad #function("<000r3e0~e1g2\x7fe2~31z3242;" [string string.rep string.count] string.rpad) string.rep #function(";000r2\x7fb4X6`0e0\x7f`32650c1;\x7faW680e2~41;\x7fb2W690e2~~42;e2~~~43;e3\x7f316@0e2~e4~\x7faz3242;e4e2~~32\x7fb2U242;" [<= "" string odd? string.rep] string.rep) string.map #function("9000r2c0e130e2\x7f31u43;" [#function("8000vc0`u322e1~41;" [#function(";000v^~\x81X6S02e0\x80i10e1i11~3231322e2i11~32m05\x0b/;" [io.putc string.char string.inc]) io.tostring!]) buffer length] string.map) string.lpad #function(";000r3e0e1g2\x7fe2~31z32~42;" [string string.rep string.count] string.lpad) string.join #function("8000r2~\x8750c0;c1e230u42;" ["" #function("8000ve0~\x80M322e1c2q\x80N322e3~41;" [io.write for-each #function("8000r1e0\x80i11322e0\x80~42;" [io.write]) io.tostring!]) buffer] string.join) simple-sort #function("8000r1~A17602~NA640~;c0~Mu42;" [#function("9000vc0e1c2q\x80N32u42;" [#function(":000ve0e1~M31\x80L1e1~N3143;" [nconc simple-sort]) separate #function("7000r1~\x80X;" [])])] simple-sort) set-syntax! #function("9000r2e0e1~\x7f43;" [put! *syntax-environment*] set-syntax!) separate #function(":000r2\x80~\x7f__44;" [] #0=[#function("6000r4\x7f\x8780g2g3K;~\x7fM316@0\x80~\x7fN\x7fMg2Kg344;\x80~\x7fNg2\x7fMg3K44;" [] #0#) ()]) self-evaluating? #function("8000r1~?16602~C@17K02e0~3116A02~C16:02~e1~31<;" [constant? top-level-value] self-evaluating?) reverse! #function("8000r1c0_u42;" [#function("9000v^\x80F6C02\x80N\x80~\x80m02P2o005\x1c/2~;" [])] reverse!) reverse #function("9000r1e0c1_~43;" [foldl #.cons] reverse) revappend #function("8000r2e0e1~31\x7f42;" [nconc reverse] revappend) repl #function("9000r0c0^^u43;" [#function("6000vc0m02c1qm12\x7f302e240;" [#function("8000r0e0c1312e2e3312c4c5c6tu
\ No newline at end of file
+(*banner* ";  _\n; |_ _ _ |_ _ |  . _ _\n; | (-||||_(_)|__|_)|_)\n;-------------------|----------------------------------------------------------\n\n" *syntax-environment* #table(assert #function("<000r1c0~]c1c2c3~L2L2L2L4;" [if raise quote assert-failed])  letrec #function("?000s1e0e0c1L1e2c3~32L1e2c4~32e5\x7f3134L1e2c6~3242;" [nconc lambda map #.car #function("9000r1e0c1L1e2~3142;" [nconc set! copy-list]) copy-list #function("6000r1^;" [])])  backquote #function("7000r1e0~41;" [bq-process])  label #function(":000r2c0~L1c1~\x7fL3L3^L2;" [lambda set!])  do #function("A000s2c0e130\x7fMe2c3~32e2e4~32e2c5~32u46;" [#function("B000vc0~c1g2c2\x7fe3c4L1e5\x81N3132e3c4L1e5i0231e3~L1g432L133L4L3L2L1e3~L1g332L3;" [letrec lambda if nconc begin copy-list]) gensym map #.car cadr #function("7000r1e0~31F680e1~41;~M;" [cddr caddr])])  when #function("<000s1c0~c1\x7fK^L4;" [if begin])  unwind-protect #function("9000r2c0e130e130u43;" [#function("@000vc0\x7fc1_\x81L3L2L1c2c3\x80c1~L1c4\x7fL1c5~L2L3L3L3\x7fL1L3L3;" [let lambda prog1 trycatch begin raise]) gensym])  dotimes #function("<000s1c0~M~\x86u43;" [#function("=000vc0`c1\x7faL3e2c3L1~L1L1e4\x813133L4;" [for - nconc lambda copy-list])])  define-macro #function("?000s1c0c1~ML2e2c3L1~NL1e4\x7f3133L3;" [set-syntax! quote nconc lambda copy-list])  receive #function("@000s2c0c1_\x7fL3e2c1L1~L1e3g23133L3;" [call-with-values lambda nconc copy-list])  unless #function("=000s1c0~^c1\x7fKL4;" [if begin])  let #function(";000s1c0^u42;" [#function("<000v\x80C6D0\x80m02\x81Mo002\x81No01530^2c0e1c2L1e3c4\x8032L1e5\x813133e3c6\x8032u43;" [#function("8000v\x806;0c0\x80~L3530~\x7fK;" [label]) nconc lambda map #function("6000r1~F650~M;~;" []) copy-list #function("6000r1~F650~\x86;^;" [])])])  cond #function(":000s0c0^u42;" [#function("7000vc0qm02~\x8041;" [#function("8000r1~?640^;c0~Mu42;" [#function(";000v~Mc0<17702~M]<6@0~N\x8750~M;c1~NK;~N\x87@0c2~Mi10\x80N31L3;c3~Mc1~NKi10\x80N31L4;" [else begin or if])] cond-clauses->if)])])  throw #function(":000r2c0c1c2c3L2~\x7fL4L2;" [raise list quote thrown-value])  time #function("8000r1c0e130u42;" [#function(">000vc0~c1L1L2L1c2\x80c3c4c5c1L1~L3c6L4L3L3;" [let time.now prog1 princ "Elapsed time: " - " seconds\n"]) gensym])  let* #function("A000s1~?6E0e0c1L1_L1e2\x7f3133L1;e0c1L1e3~31L1L1e2~NF6H0e0c4L1~NL1e2\x7f3133L1530\x7f3133e5~31L2;" [nconc lambda copy-list caar let* cadar])  case #function(";000s1c0^u42;" [#function("8000vc0m02c1e230u42;" [#function(";000r2\x7fc0\x8450c0;\x7f\x8740^;\x7fC6=0c1~e2\x7f31L3;\x7f?6=0c3~e2\x7f31L3;\x7fN\x87>0c3~e2\x7fM31L3;e4c5\x7f326=0c6~c7\x7fL2L3;c8~c7\x7fL2L3;" [else eq? quote-value eqv? every #.symbol? memq quote memv] vals->cond) #function("<000vc0~i10L2L1e1c2L1e3c4qi113232L3;" [let nconc cond map #function("8000r1i10\x80~M32~NK;" [])]) gensym])])  catch #function("8000r2c0e130u42;" [#function("@000vc0\x81c1~L1c2c3c4~L2c5c6~L2c7c8L2L3c5c9~L2\x80L3L4c:~L2c;~L2L4L3L3;" [trycatch lambda if and pair? eq car quote thrown-value cadr caddr raise]) gensym])) *whitespace* "\t\n\v\f\r \u0085  ᠎           \u2028\u2029   " /= #function("7000r2~\x7fW@;" [] /=) 1+ #function("7000r1~ay;" [] 1+) 1- #function("7000r1~az;" [] 1-) 1arg-lambda? #function("8000r1~F16T02~Mc0<16J02~NF16B02~\x86F16:02e1~\x86a42;" [lambda length=] 1arg-lambda?) <= #function("7000r2~\x7fX17602~\x7fW;" [] <=) > #function("7000r2\x7f~X;" [] >) >= #function("7000r2\x7f~X17602~\x7fW;" [] >=) Instructions #table(:sub2 74  :nop 0  :set-cdr! 32  :/ 37  :setc 63  :tapply 72  :lvargc 77  :cons 27  :loada1 79  :tcall.l 83  dummy_nil 94  :equal? 14  :cdr 30  :call 3  :eqv? 13  := 39  :setg.l 60  :list 28  :atom? 15  :aref 43  :load0 48  :let 70  dummy_t 92  :argc 66  :brne.l 85  :< 40  :null? 17  :loadg 53  :load1 49  :car 29  :brt.l 10  :vargc 67  :loada 55  :set-car! 31  :setg 59  :aset! 44  :loadc01 81  :bound? 21  :optargs 91  :pair? 22  :symbol? 19  :brn 89  :fixnum? 25  :loadi8 50  :not 16  :* 36  :neg 75  :pop 2  :largc 76  :loadnil 47  :brf 6  :vector 42  :- 35  :loadv 51  :loada.l 56  :seta.l 62  :closure 65  :loadc00 80  :number? 2
\ No newline at end of file
--- a/femtolisp/flisp.c
+++ b/femtolisp/flisp.c
@@ -931,6 +931,30 @@
             Stack[SP-1] = 0;
             curr_frame = SP;
             NEXT_OP;
+        OP(OP_OPTARGS)
+            n = GET_INT32(ip); ip+=4;
+            v = fn_vals(Stack[bp-1]);
+            v = vector_elt(v, 0);
+            if (nargs >= n) {  // if we have all required args
+                s = vector_size(v);
+                n += s;
+                if (nargs < n) {  // but not all optional args
+                    i = n - nargs;
+                    SP += i;
+                    Stack[SP-1] = Stack[SP-i-1];
+                    Stack[SP-2] = Stack[SP-i-2];
+                    Stack[SP-3] = Stack[SP-i-3];
+                    Stack[SP-4] = Stack[SP-i-4];
+                    Stack[SP-5] = Stack[SP-i-5];
+                    curr_frame = SP;
+                    s = s - i;
+                    for(n=0; n < i; n++) {
+                        Stack[bp+nargs+n] = vector_elt(v, s+n);
+                    }
+                    nargs += i;
+                }
+            }
+            NEXT_OP;
         OP(OP_NOP) NEXT_OP;
         OP(OP_DUP) SP++; Stack[SP-1] = Stack[SP-2]; NEXT_OP;
         OP(OP_POP) POPN(1); NEXT_OP;
@@ -1662,7 +1686,7 @@
 #endif
 }
 
-static uint32_t compute_maxstack(uint8_t *code, size_t len)
+static uint32_t compute_maxstack(uint8_t *code, size_t len, value_t vals)
 {
     uint8_t *ip = code+4, *end = code+len;
     uint8_t op;
@@ -1688,6 +1712,12 @@
             sp += (n+2);
             break;
         case OP_LET: break;
+        case OP_OPTARGS:
+            ip += 4;
+            assert(isvector(vals));
+            if (vector_size(vals) > 0)
+                sp += vector_size(vector_elt(vals, 0));
+            break;
 
         case OP_TCALL: case OP_CALL:
             n = *ip++;  // nargs
@@ -1824,7 +1854,7 @@
         for(i=0; i < sz; i++)
             data[i] -= 48;
     }
-    uint32_t ms = compute_maxstack((uint8_t*)data, cv_len(arr));
+    uint32_t ms = compute_maxstack((uint8_t*)data, cv_len(arr), args[1]);
     PUT_INT32(data, ms);
     function_t *fn = (function_t*)alloc_words(4);
     value_t fv = tagptr(fn, TAG_FUNCTION);
--- a/femtolisp/opcodes.h
+++ b/femtolisp/opcodes.h
@@ -27,6 +27,7 @@
     OP_TAPPLY, OP_ADD2, OP_SUB2, OP_NEG, OP_LARGC, OP_LVARGC,
     OP_LOADA0, OP_LOADA1, OP_LOADC00, OP_LOADC01, OP_CALLL, OP_TCALLL,
     OP_BRNE, OP_BRNEL, OP_CADR, OP_BRNN, OP_BRNNL, OP_BRN, OP_BRNL,
+    OP_OPTARGS,
 
     OP_BOOL_CONST_T, OP_BOOL_CONST_F, OP_THE_EMPTY_LIST,
 
@@ -69,7 +70,7 @@
     &&L_OP_LVARGC,                                                      \
     &&L_OP_LOADA0, &&L_OP_LOADA1, &&L_OP_LOADC00, &&L_OP_LOADC01,       \
     &&L_OP_CALLL, &&L_OP_TCALLL, &&L_OP_BRNE, &&L_OP_BRNEL, &&L_OP_CADR,\
-    &&L_OP_BRNN, &&L_OP_BRNNL, &&L_OP_BRN, &&L_OP_BRNL                  \
+    &&L_OP_BRNN, &&L_OP_BRNNL, &&L_OP_BRN, &&L_OP_BRNL, &&L_OP_OPTARGS  \
     }
 
 #define VM_APPLY_LABELS                                                 \
--- a/femtolisp/system.lsp
+++ b/femtolisp/system.lsp
@@ -224,15 +224,16 @@
 		(set-car! lst (f (car lst)))
 		(set! lst (cdr lst)))))
 
-(define filter
-  (letrec ((filter-
-	    (lambda (pred lst accum)
-	      (cond ((null? lst) accum)
-		    ((pred (car lst))
-		     (filter- pred (cdr lst) (cons (car lst) accum)))
-		    (#t
-		     (filter- pred (cdr lst) accum))))))
-    (lambda (pred lst) (filter- pred lst ()))))
+(define (filter pred lst)
+  (define (filter- f lst acc)
+    (cdr
+     (prog1 acc
+      (while (pair? lst)
+	     (begin (if (pred (car lst))
+			(set! acc
+			      (cdr (set-cdr! acc (cons (car lst) ())))))
+		    (set! lst (cdr lst)))))))
+  (filter- pred lst (list ())))
 
 (define separate
   (letrec ((separate-
--- a/femtolisp/todo
+++ b/femtolisp/todo
@@ -159,7 +159,7 @@
   . write a function to evaluate directly from list to list, use it for
     Nth arg and for user function rest args
   . modify vararg builtins accordingly
-- filter should be stable. right now it reverses.
+* filter should be stable. right now it reverses.
 
 
 femtoLisp3...with symbolic C interface
@@ -975,7 +975,8 @@
 - remaining c types
 - remaining cvalues functions
 - finish ios
-- optional and keyword arguments
+* optional arguments
+- keyword arguments
 - some kind of record, struct, or object system
 
 - special efficient reader for #array
@@ -1042,6 +1043,8 @@
 * try removing MAX_ARGS trickery
 - apply optimization, avoid redundant list copying calling vararg fns
 - let eversion
+- variable analysis - avoid holding references to values in frames
+  captured by closures but not used inside them
 * lambda lifting
 * let optimization
 * fix equal? on functions
--- a/femtolisp/unittest.lsp
+++ b/femtolisp/unittest.lsp
@@ -116,6 +116,14 @@
 (assert (equal? (apply f (iota 995))  '(994)))
 (assert (equal? (apply f (iota 1000)) '(994 995 996 997 998 999)))
 
+; optional arguments
+(assert (equal? ((lambda ((b 0)) b)) 0))
+(assert (equal? ((lambda (a (b 2)) (list a b)) 1) '(1 2)))
+(assert (equal? ((lambda (a (b 2)) (list a b)) 1 3) '(1 3)))
+(assert (equal? ((lambda (a (b 2) (c 3)) (list a b c)) 1) '(1 2 3)))
+(assert (equal? ((lambda (a (b 2) (c 3)) (list a b c)) 1 8) '(1 8 3)))
+(assert (equal? ((lambda (a (b 2) (c 3)) (list a b c)) 1 8 9) '(1 8 9)))
+
 ; ok, a couple end-to-end tests as well
 (define (fib n) (if (< n 2) n (+ (fib (- n 1)) (fib (- n 2)))))
 (assert (equal? (fib 20) 6765))