Dynamically determine which regex implementation to use:

NFA or derivatives. The default behavior is NFA, with
derivatives used if the regular expression contains
uses of complement or intersection. The --dv-regex
option forces derivatives always.

1 files changed, 4 insertions, 0 deletions

diff --git a/txr.c b/txr.c
index 16faa19a..ff1397f7 100644
--- a/txr.c
+++ b/txr.c
@@ -281,6 +281,10 @@ int txr_main(int argc, char **argv)
              prog_string, string_utf8(*argv), nao);
       return EXIT_FAILURE;
 #endif
+    } else if (!strcmp(*argv, "--dv-regex")) {
+      opt_derivative_regex = 1;
+      argv++, argc--;
+      continue;
     }
 
     {