add LL backend stub

src/Makefile

@@ -26,7 +26,8 @@ PARSERS := \
 	indirect
 
 BACKENDS := \
-	packrat
+	packrat \
+	ll
 
 HAMMER_PARTS := \
 	bitreader.o \

src/backends/ll.c

@@ -0,0 +1,17 @@
+#include <assert.h>
+#include "../internal.h"
+#include "../parsers/parser_internal.h"
+
+
+int h_ll_compile(HAllocator* mm__, const HParser* parser, const void* params) {
+  return -1; // TODO
+}
+
+HParseResult *h_ll_parse(HAllocator* mm__, const HParser* parser, HParseState* parse_state) {
+  return NULL; // TODO
+}
+
+HParserBackendVTable h__ll_backend_vtable = {
+  .compile = h_ll_compile,
+  .parse = h_ll_parse
+};

src/compile.c

@@ -4,6 +4,7 @@
 
 static HParserBackendVTable *backends[PB_MAX] = {
   &h__packrat_backend_vtable,
+  &h__ll_backend_vtable,
 };
 
 int h_compile(const HParser* parser, HParserBackend backend, const void* params) {

src/hammer.h

@@ -34,6 +34,7 @@ typedef struct HParseState_ HParseState;
 typedef enum HParserBackend_ {
   PB_MIN = 0,
   PB_PACKRAT = PB_MIN, // PB_MIN is always the default.
+  PB_LL,
   PB_MAX
 } HParserBackend;
 

src/internal.h

@@ -215,6 +215,7 @@ struct HBitWriter_ {
 
 // Backends {{{
 extern HParserBackendVTable h__packrat_backend_vtable;
+extern HParserBackendVTable h__ll_backend_vtable;
 // }}}
 
 // TODO(thequux): Set symbol visibility for these functions so that they aren't exported.