:sparkles: (Janet) chapter 4 and 5

Janet/chapter4/html-prettier.janet

···
+(defn element-to-struct [tag attrs children]
+  {:tag tag :attrs (struct ;attrs) :children children})
+
+(def html-peg (peg/compile
+	       ~{:main (* :nodes -1)
+		 :nodes (any (+ :element :text))
+		 :element (unref
+			   {:main (/ (* :open-tag (group :nodes) :close-tag) ,element-to-struct)
+			    :open-tag (* "<" (<- :w+ :tag-name) (group (? (* :s+ :attributes))) ">")
+			    :attributes
+			      {:main (some (* :attribute (? :s+)))
+			       :attribute (* (<- :w+) "=" :quoted-string)
+			       :quoted-string (* `"` (<- (any (if-not `"` 1))) `"`)}
+			    :close-tag (* "</" (backmatch :tag-name) ">")})
+		 :text (<- (some (if-not "<" 1)))}))
+
+(defn main [&]
+  (def input (string/trim (file/read stdin :all)))
+  (pp (peg/match html-peg input)))

Janet/chapter5/blocking.janet

···
+(defn print-dots []
+  (while true
+    (prin ".")
+    (flush)
+    (ev/sleep 0)))
+
+(ev/call print-dots)
+
+(def f (file/open "lorem-ipsum.txt" :r))
+(print "About to read")
+(def bytes (file/read f 10))
+(print "Done reading")
+(file/close f)
+(print "Done closing the file")
+(printf "read %q" bytes)
+(os/exit 0)

Janet/chapter5/dynamic.janet

···
+(def file (file/open "output.txt" :w))
+(print "everything is normal")
+(with-dyns [*out* file]
+  (print "but this writes to a file"))
+(print "back to normal")

Janet/chapter5/event-loop.janet

···
+(defn visualize-time []
+  (var stopped false)
+  (while (not stopped)
+    (prin ".")
+    (flush)
+    (if (= (ev/sleep 0.1) :stop)
+      (set stopped true))))
+
+(def background-fiber (ev/call visualize-time))
+
+(print "hello")
+(ev/sleep 1)
+(print "goodbye")
+
+(ev/go background-fiber :stop)

Janet/chapter5/fiber-caught.janet

···
+(defn do-your-best []
+  (error "oh no"))
+
+(defn believe-in-yourself []
+  (while true
+    (do-your-best)))
+
+(def fiber (fiber/new believe-in-yourself :e))
+(resume fiber)

Janet/chapter5/fiber.janet

···
+(defn print-something []
+  (print "something"))
+
+(def fiber (fiber/new print-something))
+(resume fiber)
+
+(defn range [count]
+  (for i 0 count
+    (yield i))
+  "done")
+
+(def fiber (fiber/new (fn [] (range 5))))
+
+(each value fiber
+  (print value))
+
+(defn yield-twice [x]
+  (yield x)
+  (yield x))
+
+(defn double-range [count]
+  (for i 0 count
+    (yield-twice i)))
+
+(def fiber (fiber/new (fn [] (double-range 5))))
+(each value fiber
+  (print value))

Janet/chapter5/fiberror.janet

···
+(defn do-your-best []
+  (error "oh no"))
+
+(defn believe-in-yourself []
+  (while true
+    (do-your-best)))
+
+(def fiber (fiber/new believe-in-yourself))
+(resume fiber)

Janet/chapter5/lorem-ipsum.txt

···
+Lorem ipsum dolor sit amet.

Janet/chapter5/output.txt

···
+but this writes to aa file

Janet/chapter5/streams.janet

···
+(defn print-dots []
+  (while true
+    (prin ".")
+    (flush)
+    (ev/sleep 0)))
+
+(ev/call print-dots)
+
+(def f (os/open "lorem-ipsum.txt" :r))
+(print "About to read")
+(def bytes (ev/read f 10))
+(print "Done reading")
+(ev/close f)
+(print "Done closing the file")
+(printf "read %q" bytes)
+(os/exit 0)