cleanup and bugfixing on domain parser

examples/glue.c

@@ -1,4 +1,5 @@
 #include "glue.h"
+#include "../src/internal.h"  // for h_carray_*
 
 
 // The action equivalent of h_ignore.
@@ -31,10 +32,68 @@ const HParsedToken *act_index0(const HParseResult *p)
     return act_index(0, p);
 }
 
-HParsedToken *h_make_token(HArena *arena, HTokenType type, void *value)
+void h_seq_snoc(HParsedToken *xs, const HParsedToken *x)
+{
+  assert(xs != NULL);
+  assert(xs->token_type == TT_SEQUENCE);
+
+  h_carray_append(xs->seq, (void *)x);
+}
+
+void h_seq_append(HParsedToken *xs, const HParsedToken *ys)
+{
+  assert(xs != NULL);
+  assert(xs->token_type == TT_SEQUENCE);
+  assert(ys != NULL);
+  assert(ys->token_type == TT_SEQUENCE);
+
+  for(size_t i; i<ys->seq->used; i++)
+	h_carray_append(xs->seq, ys->seq->elements[i]);
+}
+
+// Flatten nested sequences. Always returns a sequence.
+// If input element is not a sequence, returns it as a singleton sequence.
+const HParsedToken *h_token_flatten(HArena *arena, const HParsedToken *p)
+{
+  assert(p != NULL);
+
+  HParsedToken *ret = h_make_token_seq(arena);
+  switch(p->token_type) {
+  case TT_SEQUENCE:
+    // Flatten and append all.
+    for(size_t i; i<p->seq->used; i++) {
+	  h_seq_append(ret, h_token_flatten(arena, h_seq_index(p, i)));
+	}
+	break;
+  default:
+    // Make singleton sequence.
+    h_seq_snoc(ret, p);
+	break;
+  }
+
+  return ret;
+}
+
+// Action version of h_token_flatten.
+const HParsedToken *act_flatten(const HParseResult *p) {
+  return h_token_flatten(p->arena, p->ast);
+}
+
+HParsedToken *h_make_token_(HArena *arena, HTokenType type)
 {
   HParsedToken *ret = h_arena_malloc(arena, sizeof(HParsedToken));
   ret->token_type = type;
+  return ret;
+}
+
+HParsedToken *h_make_token_seq(HArena *arena)
+{
+  return h_make_token_(arena, TT_SEQUENCE);
+}
+
+HParsedToken *h_make_token(HArena *arena, HTokenType type, void *value)
+{
+  HParsedToken *ret = h_make_token_(arena, type);
   ret->user = value;
   return ret;
 }