Drop leading and trailing newlines in longstrings.

Long, heredoc style strings can now have
a non semantic leading newline character. This makes it
easier to define large columns of text.

examples/numarray/build.janet

@@ -4,7 +4,7 @@
     :name "numarray"
     :source @["numarray.c"])
 
-(import build/numarray :prefix "")
+(import build/numarray :as numarray)
 
 (def a (numarray/new 30))
 (print (get a 20))

examples/numarray/numarray.c

@@ -100,12 +100,12 @@ Janet num_array_get(void *p, Janet key) {
 
 static const JanetReg cfuns[] = {
     {
-        "numarray/new", num_array_new,
+        "new", num_array_new,
         "(numarray/new size)\n\n"
         "Create new numarray"
     },
     {
-        "numarray/scale", num_array_scale,
+        "scale", num_array_scale,
         "(numarray/scale numarray factor)\n\n"
         "scale numarray by factor"
     },

src/core/parse.c

@@ -257,12 +257,24 @@ static int escape1(JanetParser *p, JanetParseState *state, uint8_t c) {
 
 static int stringend(JanetParser *p, JanetParseState *state) {
     Janet ret;
+    uint8_t *bufstart = p->buf;
+    int32_t buflen = (int32_t) p->bufcount;
+    if (state->flags & PFLAG_LONGSTRING) {
+        /* Check for leading newline character so we can remove it */
+        if (bufstart[0] == '\n') {
+            bufstart++;
+            buflen--;
+        }
+        if (buflen > 0 && bufstart[buflen - 1] == '\n') {
+            buflen--;
+        }
+    }
     if (state->flags & PFLAG_BUFFER) {
-        JanetBuffer *b = janet_buffer((int32_t)p->bufcount);
-        janet_buffer_push_bytes(b, p->buf, (int32_t)p->bufcount);
+        JanetBuffer *b = janet_buffer(buflen);
+        janet_buffer_push_bytes(b, bufstart, buflen);
         ret = janet_wrap_buffer(b);
     } else {
-        ret = janet_wrap_string(janet_string(p->buf, (int32_t)p->bufcount));
+        ret = janet_wrap_string(janet_string(bufstart, buflen));
     }
     p->bufcount = 0;
     popstate(p, ret);