a major refactoring in the C and the Haskell runtimes. Note incompatible change in the PGF format!!!

The following are the outcomes:

   - Predef.nonExist is fully supported by both the Haskell and the C runtimes

   - Predef.BIND is now an internal compiler defined token. For now
     it behaves just as usual for the Haskell runtime, i.e. it generates &+.
     However, the special treatment will let us to handle it properly in 
     the C runtime.

   - This required a major change in the PGF format since both 
     nonExist and BIND may appear inside 'pre' and this was not supported
     before.

1 files changed, 12 insertions, 19 deletions

diff --git a/src/runtime/c/pgf/reader.c b/src/runtime/c/pgf/reader.c
index 95b5a4c04..ebc5050e4 100644
--- a/src/runtime/c/pgf/reader.c
+++ b/src/runtime/c/pgf/reader.c
@@ -586,27 +586,13 @@ pgf_read_printnames(PgfReader* rdr)
 	return printnames;
 }
 
-static PgfTokens*
-pgf_read_tokens(PgfReader* rdr)
-{
-	size_t len = pgf_read_len(rdr);
-	gu_return_on_exn(rdr->err, NULL);
-
-	PgfTokens* tokens = gu_new_seq(PgfToken, len, rdr->opool);
-	for (size_t i = 0; i < len; i++) {
-		PgfToken token = pgf_read_string(rdr);
-		gu_return_on_exn(rdr->err, NULL);
-
-		gu_seq_set(tokens, PgfToken, i, token);
-	}
-
-	return tokens;
-}
+static PgfSequence*
+pgf_read_sequence(PgfReader* rdr);
 
 static void
 pgf_read_alternative(PgfReader* rdr, PgfAlternative* alt)
 {
-	alt->form = pgf_read_tokens(rdr);
+	alt->form = pgf_read_sequence(rdr);
 	gu_return_on_exn(rdr->err,);
 
 	size_t n_prefixes = pgf_read_len(rdr);
@@ -672,12 +658,12 @@ pgf_read_symbol(PgfReader* rdr)
 			gu_new_variant(PGF_SYMBOL_KS,
 						   PgfSymbolKS,
 						   &sym, rdr->opool);
-		sym_ks->tokens = pgf_read_tokens(rdr);
+		sym_ks->token = pgf_read_string(rdr);
 		gu_return_on_exn(rdr->err, gu_null_variant);
 		break;
 	}
 	case PGF_SYMBOL_KP: {
-		PgfTokens* default_form = pgf_read_tokens(rdr);
+		PgfSequence* default_form = pgf_read_sequence(rdr);
 		gu_return_on_exn(rdr->err, gu_null_variant);
 		
 		size_t n_forms = pgf_read_len(rdr);
@@ -703,6 +689,13 @@ pgf_read_symbol(PgfReader* rdr)
 		gu_return_on_exn(rdr->err, gu_null_variant);
 		break;
 	}
+	case PGF_SYMBOL_BIND: {
+		gu_new_variant(PGF_SYMBOL_BIND,
+		               PgfSymbolBIND,
+		               &sym, rdr->opool);
+		gu_return_on_exn(rdr->err, gu_null_variant);
+		break;
+	}
 	default:
 		pgf_read_tag_error(rdr);
 	}