spork/stream: add make-stdin, make-stdout, and make-stderr

Author: amano-kenji

spork/stream.janet

@@ -26,3 +26,18 @@
         (when (not (empty? chunk))
           (yield chunk)))))
   (coro (fetch-lines @"")))
+
+(defn make-stdin
+  "Return a readable stream on /dev/stdin"
+  []
+  (os/open "/dev/stdin" :r))
+
+(defn make-stdout
+  "Return a writable stream on /dev/stdout"
+  []
+  (os/open "/dev/stdout" :w))
+
+(defn make-stderr
+  "Return a writable stream on /dev/stderr"
+  []
+  (os/open "/dev/stderr" :w))