Add file/lines iterator

src/boot/boot.janet

@@ -1749,6 +1749,19 @@
   (printf (dyn *pretty-format* "%q") x)
   (flush))
 
+(defn file/lines
+  "Return an iterator over the lines of a file"
+  [file-or-path &opt mode]
+  (default mode :r)
+  (if (bytes? file-or-path)
+    (coro
+      (with [f (file/open file-or-path mode)]
+        (while (def line (file/read f :line))
+          (yield line))))
+    (coro
+      (while (def line (file/read file-or-path :line))
+        (yield line)))))
+
 ###
 ###
 ### Pattern Matching

test/suite0009.janet

@@ -102,6 +102,19 @@
     (os/execute [janet "-e" `(repeat 20 (print :hello))`] :p {:out f})
     (file/flush f)))
 
+# each-line iterator
+
+(assert-no-error "file/lines iterator"
+   (def outstream (os/open "unique.txt" :wct))
+   (def buf1 "123\n456\n")
+   (defer (:close outstream)
+     (:write outstream buf1))
+   (var buf2 "")
+   (each line (file/lines "unique.txt")
+      (set buf2 (string buf2 line)))
+   (assert (= buf1 buf2) "file/lines iterator")
+   (os/rm "unique.txt"))
+
 # Issue #593
 (assert-no-error "file writing 3"
   (def outfile (file/open "unique.txt" :w))