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, 3 insertions, 0 deletions

diff --git a/src/serdi.c b/src/serdi.c
index 1925cd88..2801a2da 100644
--- a/src/serdi.c
+++ b/src/serdi.c
@@ -72,6 +72,7 @@ print_usage(const char* name, bool error)
   fprintf(os, "  -s INPUT     Parse INPUT as string.\n");
   fprintf(os, "  -t           Write terser output without newlines.\n");
   fprintf(os, "  -v           Display version information and exit.\n");
+  fprintf(os, "  -x           Support parsing variable nodes like `?x'.\n");
   return error ? 1 : 0;
 }
 
@@ -246,6 +247,8 @@ main(int argc, char** argv)
         return missing_arg(argv[0], 'w');
       }
       out_filename = argv[a];
+    } else if (argv[a][1] == 'x') {
+      reader_flags |= SERD_READ_VARIABLES;
     } else {
       SERDI_ERRORF("invalid option -- '%s'\n", argv[a] + 1);
       return print_usage(argv[0], true);