initial commit

Now the rough framework is established and the grammar class is sort
of ready.

It remains to write a general input reading mechanism.

1 files changed, 106 insertions, 0 deletions

diff --git a/src/grammar.c b/src/grammar.c
new file mode 100644
index 0000000..9265ef5
--- /dev/null
+++ b/src/grammar.c
@@ -0,0 +1,106 @@
+#include "grammar.h"
+
+struct TNT_s {
+  int type;                     /* 0 => T and NT otherwise */
+  union { T t; NT nt; } data;
+};
+
+struct Rule_s {
+  NT left;
+  List *right;
+};
+
+TNT *new_tnt(int type, ...)
+{
+  va_list args;
+  va_start(args, type);
+
+  TNT *result = MYALLOC(TNT, 1);
+  result->type = type;
+
+  if (type) result->data.nt = va_arg(args, NT);
+  else result->data.t = va_arg(args, T);
+
+  va_end(args);
+
+  return result;
+}
+
+Rule *new_rule(NT left, List *right)
+{
+  if (!right) return NULL;
+  
+  Rule *rule = MYALLOC(Rule, 1);
+
+  rule->left = left;
+  rule->right = right;
+
+  return rule;
+}
+
+void print_tnt(void *element)
+{
+  TNT *tnt = (TNT*) element;
+
+  if (tnt->type)
+    printf("NT %u, ", tnt->data.nt);
+  else
+    printf("T %lu, ", tnt->data.t);
+}
+
+void print_rule(void *r)
+{
+  Rule *rule = (Rule *)r;
+  printf("Rule: NT %u => ", rule->left);
+  
+  map_list(rule->right, print_tnt);
+
+  printf("\n");
+}
+
+void print_grammar(Grammar g)
+{
+  printf("Printing a grammar:\n");
+  map_list(g, print_rule);
+  printf("\n");
+}
+
+List *new_tnt_string(char *format, int format_len, ...)
+{
+  /* FORMAT_LEN does not include the terminating null byte, so it
+     should be > 0. */
+  
+  if (format_len <= 0) return NULL;
+  
+  List *result = new_list();
+  
+  va_list args;
+  va_start(args, format_len);
+  
+  for (int point = 0; point < format_len; point++) {
+    switch (*(format+point)) {
+    case 'n':
+      add_to_list(result, new_tnt(1, va_arg(args, NT)));
+      break;
+    case 't':
+      add_to_list(result, new_tnt(0, va_arg(args, T)));
+      break;
+    default:
+      eprintf("Wront character: %c\n", *(format+point));
+      destroy_list(result, 1);
+      va_end(args);
+      return NULL;
+      break;
+    }
+  }
+
+  va_end(args);
+
+  return result;
+}
+
+void destroy_rule(Rule *rule)
+{
+  destroy_list(rule->right, 1);
+  free(rule);
+}