hook up LALR backend stub

src/backends/lalr.c

@@ -0,0 +1,86 @@
+#include <assert.h>
+#include "../internal.h"
+#include "../cfgrammar.h"
+#include "../parsers/parser_internal.h"
+
+
+
+void h_lalr_free(HParser *parser)
+{
+  // XXX free data structures
+  parser->backend_data = NULL;
+  parser->backend = PB_PACKRAT;
+}
+
+
+/* LALR table generation */
+
+int h_lalr_compile(HAllocator* mm__, HParser* parser, const void* params)
+{
+  return -1;
+}
+
+
+/* LR driver */
+
+HParseResult *h_lr_parse(HAllocator* mm__, const HParser* parser, HInputStream* stream)
+{
+  return NULL;
+}
+
+
+
+
+HParserBackendVTable h__lalr_backend_vtable = {
+  .compile = h_lalr_compile,
+  .parse = h_lr_parse,
+  .free = h_lalr_free
+};
+
+
+
+
+// dummy!
+int test_lalr(void)
+{
+  /* for k=2:
+
+     S -> A | B
+     A -> X Y a
+     B -> Y b
+     X -> x | ''
+     Y -> y         -- for k=3 use "yy"
+  */
+
+  // XXX make LALR example
+  HParser *X = h_optional(h_ch('x'));
+  HParser *Y = h_sequence(h_ch('y'), h_ch('y'), NULL);
+  HParser *A = h_sequence(X, Y, h_ch('a'), NULL);
+  HParser *B = h_sequence(Y, h_ch('b'), NULL);
+  HParser *p = h_choice(A, B, NULL);
+
+  HCFGrammar *g = h_cfgrammar(&system_allocator, p);
+
+  if(g == NULL) {
+    fprintf(stderr, "h_cfgrammar failed\n");
+    return 1;
+  }
+
+  h_pprint_grammar(stdout, g, 0);
+  // print states of the LR(0) automaton
+  // print LALR(1) table
+
+  if(h_compile(p, PB_LALR, NULL)) {
+    fprintf(stderr, "does not compile\n");
+    return 2;
+  }
+
+
+  HParseResult *res = h_parse(p, (uint8_t *)"xyya", 4);
+  if(res)
+    h_pprint(stdout, res->ast, 0, 2);
+  else
+    printf("no parse\n");
+
+  return 0;
+}