Remove :generate verb from loop.

Instead, one case use `:in` as with otehr data structures.

CHANGELOG.md

@@ -2,6 +2,10 @@
 All notable changes to this project will be documented in this file.
 
 ## Unreleased - ???
+- Add `fiber/last-value` to get the value that was last yielded, errored, or signaled
+  by a fiber.
+- Remove `:generate` verb from `loop` macros. Instead, use the `:in` verb
+  which will now work on fibers as well as other data structures.
 - Define `next`, `get`, and `in` for fibers. This lets
   `each`, `map`, and similar iteration macros can now iterate over fibers.
 - Remove macro `eachy`, which can be replaced by `each`.

src/boot/boot.janet

@@ -442,17 +442,6 @@
          (def ,binding ,i)
          ,body))))
 
-(defn- loop-fiber-template
-  [binding expr body]
-  (with-syms [f s]
-    (def ds (if (idempotent? binding) binding (gensym)))
-    ~(let [,f ,expr]
-       (while true
-         (def ,ds (,resume ,f))
-         (if (= :dead (,fiber/status ,f)) (break))
-         ,;(if (= ds binding) [] [~(def ,binding ,ds)])
-         ,;body))))
-
 (defn- loop1
   [body head i]
 
@@ -490,7 +479,6 @@
       :pairs (each-template binding object :pairs [rest])
       :in (each-template binding object :each [rest])
       :iterate (iterate-template binding object rest)
-      :generate (loop-fiber-template binding object [rest])
       (error (string "unexpected loop verb " verb)))))
 
 (defmacro forv
@@ -564,9 +552,6 @@
 
   * :in -- iterate over the values in a data structure or fiber.
 
-  * :generate -- iterate over values yielded from a fiber. Can be paired with
-    the generator function for the producer/consumer pattern.
-
   `loop` also accepts conditionals to refine the looping further. Conditionals are of
   the form:
 
@@ -614,7 +599,7 @@
 (undef _env)
 
 (undef loop1 check-indexed for-template for-var-template iterate-template
-       each-template range-template loop-fiber-template)
+       each-template range-template)
 
 (defn sum
   "Returns the sum of xs. If xs is empty, returns 0."

test/suite0002.janet

@@ -49,7 +49,7 @@
 # Generators
 (def gen (generate [x :range [0 100] :when (pos? (% x 4))] x))
 (var gencount 0)
-(loop [x :generate gen]
+(loop [x :in gen]
   (++ gencount)
   (assert (pos? (% x 4)) "generate in loop"))
 (assert (= gencount 75) "generate loop count")

test/suite0008.janet

@@ -309,7 +309,7 @@ neldb\0\0\0\xD8\x05printG\x01\0\xDE\xDE\xDE'\x03\0marshal_tes/\x02
 # Issue 428
 (var result nil)
 (defn f [] (yield {:a :ok}))
-(assert-no-error "issue 428 1" (loop [{:a x} :generate (fiber/new f)] (set result x)))
+(assert-no-error "issue 428 1" (loop [{:a x} :in (fiber/new f)] (set result x)))
 (assert (= result :ok) "issue 428 2")
 
 # Inline 3 argument get