allow #f argument to continuation-mark-set->{list[*],iterator}

There's a small performance advantage in avoiding a call to
`(current-continuation-marks)`. CS already allowed #f, but did not
handle it correctly.

pkgs/racket-doc/scribblings/reference/cont-marks.scrbl

@@ -77,40 +77,33 @@ other words, it produces the same value as
 ]}
 
 @defproc[(continuation-mark-set->list
-          [mark-set continuation-mark-set?]
+          [mark-set (or/c continuation-mark-set? #f)]
           [key-v any/c]
           [prompt-tag continuation-prompt-tag? (default-continuation-prompt-tag)])
          list?]{
 Returns a newly-created list containing the marks for @racket[key-v]
 in @racket[mark-set], which is a set of marks returned by
-@racket[current-continuation-marks]. The result list is truncated at
+@racket[current-continuation-marks] or @racket[#f] as a shorthand for
+@racket[(current-continuation-marks prompt-tag)]. The result list is truncated at
 the first point, if any, where continuation frames were originally
 separated by a prompt tagged with @racket[prompt-tag]. Producing the result
 takes time proportional to the size of the continuation reflected by
-@racket[mark-set].}
+@racket[mark-set].
 
-@defproc*[([(make-continuation-mark-key) continuation-mark-key?]
+@history[#:changed "8.0.0.1" @elem{Changed to allow @racket[mark-set] as @racket[#f].}]}
-           [(make-continuation-mark-key [sym symbol?]) continuation-mark-key?])]{
-Creates a continuation mark key that is not @racket[equal?] to the result
-of any other value (including prior and future results from
-@racket[make-continuation-mark-key]). The continuation mark key can be used
-as the key argument for @racket[with-continuation-mark] or accessor procedures
-like @racket[continuation-mark-set-first]. The mark key can be chaperoned
-or impersonated, unlike other values that are used as the mark key.
 
-The optional @racket[sym] argument, if provided, is used when printing
-the continuation mark.
-}
 
 @defproc[(continuation-mark-set->list*
-          [mark-set continuation-mark-set?]
+          [mark-set (or/c continuation-mark-set? #f)]
           [key-list (listof any/c)]
           [none-v any/c #f]
           [prompt-tag continuation-prompt-tag? (default-continuation-prompt-tag)])
          (listof vector?)]{
 Returns a newly-created list containing vectors of marks in
 @racket[mark-set] for the keys in @racket[key-list], up to
-@racket[prompt-tag]. The length of each vector in the result list is
+@racket[prompt-tag], where a @racket[#f] value for @racket[mark-set]
+is equivalent to @racket[(current-continuation-marks prompt-tag)].
+The length of each vector in the result list is
 the same as the length of @racket[key-list], and a value in a
 particular vector position is the value for the corresponding key in
 @racket[key-list]. Values for multiple keys appear in a single vector
@@ -118,10 +111,13 @@ only when the marks are for the same continuation frame in
 @racket[mark-set]. The @racket[none-v] argument is used for vector
 elements to indicate the lack of a value. Producing the result
 takes time proportional to the size of the continuation reflected by
-@racket[mark-set] times the length of @racket[key-list].}
+@racket[mark-set] times the length of @racket[key-list].
+
+@history[#:changed "8.0.0.1" @elem{Changed to allow @racket[mark-set] as @racket[#f].}]}
+
 
 @defproc[(continuation-mark-set->iterator
-          [mark-set continuation-mark-set?]
+          [mark-set (or/c continuation-mark-set? #f)]
           [key-list (listof any/c)]
           [none-v any/c #f]
           [prompt-tag continuation-prompt-tag? (default-continuation-prompt-tag)])
@@ -139,7 +135,9 @@ The time required for each step is proportional to the length of
 reflected by @racket[mark-set] between frames that have keys in
 @racket[key-list].
 
-@history[#:added "7.5.0.7"]}
+@history[#:added "7.5.0.7"
+         #:changed "8.0.0.1" @elem{Changed to allow @racket[mark-set] as @racket[#f].}]}
+
 
 @defproc[(continuation-mark-set-first 
           [mark-set (or/c continuation-mark-set? #f)]
@@ -163,6 +161,7 @@ Although @racket[#f] and @racket[(current-continuation-marks
 prompt-tag)] are equivalent for @racket[mark-set], providing @racket[#f]
 as @racket[mark-set] can enable shortcuts that make it even faster.}
 
+
 @defproc[(call-with-immediate-continuation-mark
           [key-v any/c]
           [proc (any/c . -> . any)]
@@ -198,15 +197,31 @@ continuation.
      (proc (vector-ref (car vecs) 0)))))
 ]}
 
+
+@defproc*[([(make-continuation-mark-key) continuation-mark-key?]
+           [(make-continuation-mark-key [sym symbol?]) continuation-mark-key?])]{
+Creates a continuation mark key that is not @racket[equal?] to the result
+of any other value (including prior and future results from
+@racket[make-continuation-mark-key]). The continuation mark key can be used
+as the key argument for @racket[with-continuation-mark] or accessor procedures
+like @racket[continuation-mark-set-first]. The mark key can be chaperoned
+or impersonated, unlike other values that are used as the mark key.
+
+The optional @racket[sym] argument, if provided, is used when printing
+the continuation mark.}
+
+
 @defproc[(continuation-mark-key? [v any/c]) boolean?]{
 Returns @racket[#t] if @racket[v] is a mark key created by
 @racket[make-continuation-mark-key], @racket[#f] otherwise.}
 
+
 @defproc[(continuation-mark-set? [v any/c]) boolean?]{
 Returns @racket[#t] if @racket[v] is a mark set created by
 @racket[continuation-marks] or @racket[current-continuation-marks],
 @racket[#f] otherwise.}
 
+
 @defproc[(continuation-mark-set->context [mark-set continuation-mark-set?])
           list?]{
 

pkgs/racket-test-core/tests/racket/contmark.rktl

@@ -90,6 +90,24 @@
 		    x
 		    x)))))
 
+;; Check that #f is allowed in place of marks:
+(begin
+  (test '(10)
+        values
+        (with-continuation-mark 'key3 10 (continuation-mark-set->list #f 'key3)))
+  (test '(#(10))
+        values
+        (with-continuation-mark 'key3 10 (continuation-mark-set->list* #f '(key3))))
+  (test '#(10)
+        values
+        (let-values ([(v proc) ((with-continuation-mark 'key3 10 (continuation-mark-set->iterator #f '(key3))))])
+          v))
+
+  ;; Prompt tag must be present:
+  (err/rt-test (continuation-mark-set->list #f 'key3 'none (make-continuation-prompt-tag)))
+  (err/rt-test (continuation-mark-set->list* #f '(key3) 'none (make-continuation-prompt-tag)))
+  (err/rt-test (continuation-mark-set->iterator #f '(key3) 'none (make-continuation-prompt-tag))))
+
 (wcm-test '(11) (lambda ()
 		  (with-continuation-mark 'key 10 
 		    (with-continuation-mark 'key 11

racket/src/bc/gc2/Makefile.in

@@ -602,6 +602,7 @@ EXTRA_OBJS_L = $(EXTRA_GMP) ../src/unwind.@LTO@ $(@FOREIGN_IF_USED@_OBJSLIB) $(L
 #  path.
 
 MZFWMMM = Racket.framework/Versions/$(FWVERSION)_3m/Racket
+MZFWMMM_DEST = "../Racket.framework/Versions/$(FWVERSION)_3m/Racket"
 
 MACLIBRKT_LIBS = ../libracket3m.@LIBSFX@ $(LIBRKTIO) -framework CoreFoundation
 
@@ -611,7 +612,8 @@ $(MZFWMMM): ../libracket3m.@LIBSFX@ $(LIBRKTIO)
 	rm -f Racket.framework/Racket
 	ln -s Versions/$(FWVERSION)_3m/Racket Racket.framework/Racket	
 	mkdir -p "../Racket.framework/Versions/$(FWVERSION)_3m"
-	cp "Racket.framework/Racket" "../Racket.framework/Versions/$(FWVERSION)_3m/Racket"
+	rm -f $(MZFWMMM_DEST)
+	cp "Racket.framework/Racket" $(MZFWMMM_DEST)
 
 # Depending on MACLIBRKT_LINK_MODE, use Framework or statically link the framework's code:
 MACLIBRKT_LINK_fw = -F. -framework Racket

racket/src/bc/src/fun.c

@@ -166,6 +166,7 @@ static Scheme_Object *get_set_cont_mark_by_pos(Scheme_Object *key,
                                                Scheme_Meta_Continuation *mc,
                                                MZ_MARK_POS_TYPE mpos,
                                                Scheme_Object *val);
+static Scheme_Cont_Mark_Chain *current_mark_chain(const char *who, Scheme_Object *prompt_tag);
 
 static Scheme_Object *jump_to_alt_continuation();
 static void reset_cjs(Scheme_Continuation_Jump_State *a);
@@ -7692,7 +7693,7 @@ static Scheme_Object *continuation_marks(Scheme_Thread *p,
 					 Scheme_Object *econt,
                                          Scheme_Meta_Continuation *mc,
                                          Scheme_Object *prompt_tag,
-                                         char *who,
+                                         const char *who,
 					 int just_chain,
                                          int use_boundary_prompt)
      /* cont => p is not used */
@@ -8018,6 +8019,13 @@ Scheme_Object *scheme_all_current_continuation_marks()
                             0, 1);
 }
 
+Scheme_Cont_Mark_Chain *current_mark_chain(const char *who, Scheme_Object *prompt_tag) {
+  return (Scheme_Cont_Mark_Chain *)continuation_marks(scheme_current_thread, NULL, NULL, NULL, 
+                                                      prompt_tag,
+                                                      who,
+                                                      1, 1);
+}
+
 static Scheme_Object *
 cc_marks(int argc, Scheme_Object *argv[])
 {
@@ -8141,8 +8149,9 @@ extract_cc_marks(int argc, Scheme_Object *argv[])
   Scheme_Object *pr;
   int is_chaperoned = 0;
 
-  if (!SAME_TYPE(SCHEME_TYPE(argv[0]), scheme_cont_mark_set_type)) {
+  if (SCHEME_TRUEP(argv[0])
-    scheme_wrong_contract("continuation-mark-set->list", "continuation-mark-set?", 0, argc, argv);
+      && !SAME_TYPE(SCHEME_TYPE(argv[0]), scheme_cont_mark_set_type)) {
+    scheme_wrong_contract("continuation-mark-set->list", "(or/c continuation-mark-set? #f)", 0, argc, argv);
     return NULL;
   }
   if (argc > 2) {
@@ -8160,6 +8169,9 @@ extract_cc_marks(int argc, Scheme_Object *argv[])
   } else
     prompt_tag = scheme_default_prompt_tag;
 
+  if (SCHEME_FALSEP(argv[0]))
+    chain = current_mark_chain("continuation-mark-set->list", prompt_tag);
+  else
     chain = ((Scheme_Cont_Mark_Set *)argv[0])->chain;
   key = argv[1];
 
@@ -8294,8 +8306,9 @@ do_extract_cc_markses(const char *who, int argc, Scheme_Object *argv[], int iter
   Scheme_Object *pr, **keys, *vals, *none, *prompt_tag;
   intptr_t len, i;
 
-  if (!SAME_TYPE(SCHEME_TYPE(argv[0]), scheme_cont_mark_set_type)) {
+  if (SCHEME_TRUEP(argv[0])
-    scheme_wrong_contract(who, "continuation-mark-set?", 0, argc, argv);
+      && !SAME_TYPE(SCHEME_TYPE(argv[0]), scheme_cont_mark_set_type)) {
+    scheme_wrong_contract(who, "(or/c continuation-mark-set? #f)", 0, argc, argv);
     return NULL;
   }
   len = scheme_proper_list_length(argv[1]);
@@ -8332,6 +8345,9 @@ do_extract_cc_markses(const char *who, int argc, Scheme_Object *argv[], int iter
     }
   }
 
+  if (SCHEME_FALSEP(argv[0]))
+    chain = current_mark_chain(who, prompt_tag);
+  else
     chain = ((Scheme_Cont_Mark_Set *)argv[0])->chain;
 
   if (iterator) {

racket/src/cs/rumble/control.ss

@@ -721,10 +721,7 @@
                    [(null? current-mc)
                     (unless (or (eq? tag the-default-continuation-prompt-tag)
                                 (eq? tag the-root-continuation-prompt-tag))
-                      (do-raise-arguments-error '|continuation application|
+                      (raise-no-prompt-tag '|continuation application| tag))
-                                                "continuation includes no prompt with the given tag"
-                                                exn:fail:contract:continuation
-                                                (list "tag" tag)))
                     (values accum null)]
                    [(eq? tag (strip-impersonator (metacontinuation-frame-tag (car current-mc))))
                     (values accum current-mc)]
@@ -802,9 +799,7 @@
        [(null? mc)
         (unless (or (eq? tag the-root-continuation-prompt-tag)
                     (eq? tag the-default-continuation-prompt-tag))
-          (do-raise-arguments-error who "continuation includes no prompt with the given tag"
+          (raise-no-prompt-tag who tag))
-                                    exn:fail:contract:continuation
-                                    (list "tag" tag)))
         (check-barrier-ok saw-barrier?)
         '()]
        [else
@@ -823,7 +818,7 @@
     (raise-no-prompt-tag who tag)))
 
 (define (raise-no-prompt-tag who tag)
-  (do-raise-arguments-error who "continuation includes no prompt with the given tag"
+  (do-raise-arguments-error who "no corresponding prompt in the continuation"
                             exn:fail:contract:continuation
                             (list "tag" tag)))
 
@@ -1375,15 +1370,15 @@
 (define/who continuation-mark-set->list
   (case-lambda
     [(marks key) (continuation-mark-set->list marks key the-default-continuation-prompt-tag)]
-    [(marks key prompt-tag)
+    [(marks key prompt-tag-in)
      (check who continuation-mark-set? :or-false marks)
-     (check who continuation-prompt-tag? prompt-tag)
+     (check who continuation-prompt-tag? prompt-tag-in)
-     (maybe-future-barricade prompt-tag)
+     (maybe-future-barricade prompt-tag-in)
-     (let ([prompt-tag (strip-impersonator prompt-tag)])
+     (let ([prompt-tag (strip-impersonator prompt-tag-in)])
        (let-values ([(key wrapper) (extract-continuation-mark-key-and-wrapper 'continuation-mark-set->list key)])
          (let chain-loop ([mark-chain (or (and marks
                                                (continuation-mark-set-mark-chain marks))
-                                          (current-mark-chain))])
+                                          (prune-mark-chain-suffix who prompt-tag prompt-tag-in (current-mark-chain)))])
            (cond
             [(null? mark-chain)
              null]
@@ -1427,12 +1422,15 @@
               [(v new-next)
                (values v (lambda () (loop new-next)))])))))]))
 
-(define (do-continuation-mark-set->list* who iterator? marks keys none-v prompt-tag)
+(define (do-continuation-mark-set->list* who iterator? marks keys none-v prompt-tag-in)
   (check who continuation-mark-set? :or-false marks)
   (check who list? keys)
-  (check who continuation-prompt-tag? prompt-tag)
+  (check who continuation-prompt-tag? prompt-tag-in)
-  (maybe-future-barricade prompt-tag)
+  (maybe-future-barricade prompt-tag-in)
-  (let ([prompt-tag (strip-impersonator prompt-tag)])
+  (let* ([prompt-tag (strip-impersonator prompt-tag-in)]
+         [mark-chain (or (and marks
+                              (continuation-mark-set-mark-chain marks))
+                         (prune-mark-chain-suffix who prompt-tag prompt-tag-in (current-mark-chain)))])
     (let-values ([(all-keys all-wrappers)
                   (map/2-values (lambda (k)
                                   (extract-continuation-mark-key-and-wrapper who k))
@@ -1440,9 +1438,7 @@
       (lambda ()
         (let* ([n (length all-keys)]
                [tmp (#%make-vector n)])
-          (let chain-loop ([mark-chain (or (and marks
+          (let chain-loop ([mark-chain mark-chain])
-                                                (continuation-mark-set-mark-chain marks))
-                                           (current-mark-chain))])
             (cond
              [(null? mark-chain)
               null]