regex_compile should return -1 if not a regular grammar; give backends names

src/hammer.h

@@ -46,6 +46,14 @@ typedef enum HParserBackend_ {
   PB_MAX = PB_GLR
 } HParserBackend;
 
+static const char* HParserBackendNames[] = { 
+  "Packrat",
+  "Regular",
+  "LL(k)",
+  "LALR",
+  "GLR"
+};
+
 typedef enum HTokenType_ {
   // Before you change the explicit values of these, think of the poor bindings ;_;
   TT_NONE = 1,
@@ -178,6 +186,7 @@ typedef struct HCaseResult_ {
 #else
   HResultTiming timestamp;
 #endif
+  size_t length;
 } HCaseResult;
 
 typedef struct HBackendResults_ {