Add a read-line function (Issue #97).

This reads a line of text from a file as a string. The returned string includes the trailing newline character.

This leaks memory too, because strings are not region-allocated (Issue #149)

lib/harlan/io.kfc

@@ -9,6 +9,7 @@
   (extern hscanf-float ((ptr FILE) str (ptr float)) -> int)
   (extern hscanfu64 ((ptr FILE) (ptr u64)) -> int)
   (extern hgets ((ptr FILE)) -> str)
+  (extern file-read-line ((ptr FILE)) -> str)
 
   (define (file-open name)
     (fopen name "r"))

rt/builtin.cpp

@@ -155,6 +155,16 @@ char* hgets(FILE *f) {
 	return new_str;
 }
 
+// This will leake memory (#149)
+char *file$dread$dline(FILE *f) {
+	char *buf = NULL;
+	size_t size = 0;
+
+	getline(&buf, &size, f);
+
+	return buf;
+}
+
 void flush$dstdout() {
 	cout.flush();
 }

test/read-file.kfc

@@ -11,7 +11,10 @@
            (i (file-read-int f))
            (u (file-read-u64 f))
            (flt (file-read-float f))
-           (s (file-read-string f)))
+           (s (file-read-string f))
+           (line (file-read-line f)) ;; We have to read to the end of
+                                     ;; the previous line.
+           (line (file-read-line f)))
       (fclose f)
       (println i)
       (assert (= i 42))
@@ -21,5 +24,6 @@
       (assert (< (h-abs (- flt 3.141592654)) 0.000000001))
       (println* "'" s "'")
       (assert (= s "hello"))
+      (println* "'" line "'")
+      (assert (= line "this is a line\n"))
       0)))
-

test/read-file.txt

@@ -2,3 +2,4 @@
 44
 3.141592654
 hello
+this is a line