Add empty syntax type for suppressing output

1 files changed, 11 insertions, 6 deletions

diff --git a/src/serdi.c b/src/serdi.c
index 155e570a..74b8cad4 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__)
@@ -63,7 +64,7 @@ print_usage(const char* const name, const bool error)
   fprintf(os, "  -i SYNTAX    Input syntax: turtle/ntriples/trig/nquads.\n");
   fprintf(os, "  -k BYTES     Parser stack size.\n");
   fprintf(os, "  -l           Lax (non-strict) parsing.\n");
-  fprintf(os, "  -o SYNTAX    Output syntax: turtle/ntriples/nquads.\n");
+  fprintf(os, "  -o SYNTAX    Output syntax: empty/turtle/ntriples/nquads.\n");
   fprintf(os, "  -p PREFIX    Add PREFIX to blank node IDs.\n");
   fprintf(os, "  -q           Suppress all output except data.\n");
   fprintf(os, "  -r ROOT_URI  Keep relative URIs within ROOT_URI.\n");
@@ -96,14 +97,15 @@ main(int argc, char** argv)
     return print_usage(prog, true);
   }
 
-  SerdSyntax      input_syntax  = (SerdSyntax)0;
-  SerdSyntax      output_syntax = (SerdSyntax)0;
+  SerdSyntax      input_syntax  = SERD_SYNTAX_EMPTY;
+  SerdSyntax      output_syntax = SERD_SYNTAX_EMPTY;
   SerdWriterFlags writer_flags  = 0;
   bool            from_string   = false;
   bool            from_stdin    = false;
   bool            bulk_read     = true;
   bool            bulk_write    = false;
   bool            lax           = false;
+  bool            osyntax_set   = false;
   bool            quiet         = false;
   size_t          stack_size    = 4194304;
   const char*     add_prefix    = NULL;
@@ -171,12 +173,15 @@ main(int argc, char** argv)
         stack_size = (size_t)size;
         break;
       } else if (opt == 'o') {
+        osyntax_set = true;
         if (argv[a][o + 1] || ++a == argc) {
           return missing_arg(prog, 'o');
         }
 
-        if (!(output_syntax = serd_syntax_by_name(argv[a]))) {
-          return print_usage(prog, true);
+        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);
         }
         break;
       } else if (opt == 'p') {
@@ -217,7 +222,7 @@ 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;
   }