Add empty syntax type for suppressing output

1 files changed, 9 insertions, 4 deletions

diff --git a/src/serdi.c b/src/serdi.c
index 72b7afe1..e546f463 100644
--- a/src/serdi.c
+++ b/src/serdi.c
@@ -31,6 +31,7 @@
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 #define SERDI_ERROR(msg) fprintf(stderr, "serdi: " msg)
 #define SERDI_ERRORF(fmt, ...) fprintf(stderr, "serdi: " fmt, __VA_ARGS__)
@@ -95,14 +96,15 @@ main(int argc, char** argv)
     return print_usage(argv[0], true);
   }
 
-  SerdSyntax      input_syntax  = (SerdSyntax)0;
-  SerdSyntax      output_syntax = (SerdSyntax)0;
+  SerdSyntax      input_syntax  = SERD_SYNTAX_EMPTY;
+  SerdSyntax      output_syntax = SERD_SYNTAX_EMPTY;
   SerdReaderFlags reader_flags  = 0;
   SerdWriterFlags writer_flags  = 0;
   bool            from_string   = false;
   bool            from_stdin    = false;
   bool            bulk_read     = true;
   bool            bulk_write    = false;
+  bool            osyntax_set   = false;
   bool            quiet         = false;
   size_t          stack_size    = 4194304;
   const char*     add_prefix    = NULL;
@@ -158,11 +160,14 @@ main(int argc, char** argv)
       }
       stack_size = (size_t)size;
     } else if (argv[a][1] == 'o') {
+      osyntax_set = true;
       if (++a == argc) {
         return missing_arg(argv[0], 'o');
       }
 
-      if (!(output_syntax = serd_syntax_by_name(argv[a]))) {
+      if (!strcmp(argv[a], "empty")) {
+        output_syntax = SERD_SYNTAX_EMPTY;
+      } else if (!(output_syntax = serd_syntax_by_name(argv[a]))) {
         return print_usage(argv[0], true);
       }
     } else if (argv[a][1] == 'p') {
@@ -206,7 +211,7 @@ main(int argc, char** argv)
   }
 
   const bool input_has_graphs = serd_syntax_has_graphs(input_syntax);
-  if (!output_syntax) {
+  if (!output_syntax && !osyntax_set) {
     output_syntax = input_has_graphs ? SERD_NQUADS : SERD_NTRIPLES;
   }