move api additions to glue.[ch]

examples/glue.c

@@ -0,0 +1,65 @@
+#include "glue.h"
+
+
+// The action equivalent of h_ignore.
+const HParsedToken *act_ignore(const HParseResult *p)
+{
+  return NULL;
+}
+
+// Helper to build HAction's that pick one index out of a sequence.
+const HParsedToken *act_index(int i, const HParseResult *p)
+{
+    if(!p) return NULL;
+
+    const HParsedToken *tok = p->ast;
+
+    if(!tok || tok->token_type != TT_SEQUENCE)
+        return NULL;
+
+    const HCountedArray *seq = tok->seq;
+    size_t n = seq->used;
+
+    if(i<0 || (size_t)i>=n)
+        return NULL;
+    else
+        return tok->seq->elements[i];
+}
+
+const HParsedToken *act_index0(const HParseResult *p)
+{
+    return act_index(0, p);
+}
+
+HParsedToken *h_make_token(HArena *arena, HTokenType type, void *value)
+{
+  HParsedToken *ret = h_arena_malloc(arena, sizeof(HParsedToken));
+  ret->token_type = type;
+  ret->user = value;
+  return ret;
+}
+
+#define H_MAKE(TYP) \
+  ((TYP ## _t *) h_arena_malloc(p->arena, sizeof(TYP ## _t)))
+
+#define H_MAKE_TOKEN(TYP, VAL) \
+  h_make_token(p->arena, TT_ ## TYP, VAL)
+
+HParsedToken *h_carray_index(const HCountedArray *a, size_t i)
+{
+  assert(i < a->used);
+  return a->elements[i];
+}
+
+HParsedToken *h_seq_index(const HParsedToken *p, size_t i)
+{
+  assert(p->token_type == TT_SEQUENCE);
+  return h_carray_index(p->seq, i);
+}
+
+void *h_seq_index_user(HTokenType type, const HParsedToken *p, size_t i)
+{
+  HParsedToken *elem = h_seq_index(p, i);
+  assert(elem->token_type == (HTokenType)type);
+  return elem->user;
+}