Add support for parsing variables

This adds a reader flag and serdi option for extending a syntax with support
for SPARQL-like variables, for storing things like patterns or simple queries.

1 files changed, 14 insertions, 0 deletions

diff --git a/src/writer.c b/src/writer.c
index b1404a91..fbc9dd5d 100644
--- a/src/writer.c
+++ b/src/writer.c
@@ -881,6 +881,18 @@ write_blank(SerdWriter* const        writer,
 }
 
 SERD_WARN_UNUSED_RESULT static SerdStatus
+write_variable(SerdWriter* const writer, const SerdNode* node)
+{
+  SerdStatus st = SERD_SUCCESS;
+
+  TRY(st, esink("?", 1, writer));
+  TRY(st, esink(serd_node_string(node), node->n_bytes, writer));
+
+  writer->last_sep = SEP_NONE;
+  return st;
+}
+
+SERD_WARN_UNUSED_RESULT static SerdStatus
 write_node(SerdWriter*        writer,
            const SerdNode*    node,
            const SerdField    field,
@@ -895,6 +907,8 @@ write_node(SerdWriter*        writer,
     return write_curie(writer, node, field, flags);
   case SERD_BLANK:
     return write_blank(writer, node, field, flags);
+  case SERD_VARIABLE:
+    return write_variable(writer, node);
   }
 
   return SERD_ERR_INTERNAL;