parser: show starting line of unterminated form.

* parser.y (parse): Note the line number before parsing.
If the error seems to be bad termination, issue an extra
message indicating the starting line number of the form.

1 files changed, 5 insertions, 0 deletions

diff --git a/parser.y b/parser.y
index 29814d79..139ba052 100644
--- a/parser.y
+++ b/parser.y
@@ -1887,6 +1887,7 @@ int parse_once(val stream, val name, parser_t *parser)
 int parse(parser_t *parser, val name, enum prime_parser prim)
 {
   int res = 0;
+  cnum start_line = parser->lineno;
 
   parser->errors = 0;
   parser->eof = 0;
@@ -1916,5 +1917,9 @@ int parse(parser_t *parser, val name, enum prime_parser prim)
 
   uw_catch_end;
 
+  if (parser->errors && parser->syntax_tree == nil && start_line != 1)
+    yyerrorf(parser->scanner, lit("while parsing form starting at line ~a"),
+             num(start_line), nao);
+
   return res;
 }