Go Redefine Urself™ - user configs

[sqaxomonophonen]

Hack that exploits Go Rebuild Urself™ Technology to support user configs. Demo:

#define NOB_IMPLEMENTATION
#include "nob.h"

#ifndef FOO
#define FOO "default foo"
#endif

#ifndef BAR
#define BAR "default bar"
#endif

int main(int argc, char **argv)
{
   NOB_GO_DEFINE(FOO); 
   NOB_GO_DEFINE(BAR);
   NOB_GO_REBUILD_URSELF(argc, argv);
   for (int i=1; i<argc; ++i) {
      char* arg = argv[i];
      if (strlen(argv[i]) >= 4 && 0 == memcmp(arg, "FOO=", 4)) NOB_GO_REDEFINE(FOO, arg+4);
      if (strlen(argv[i]) >= 4 && 0 == memcmp(arg, "BAR=", 4)) NOB_GO_REDEFINE(BAR, arg+4);
   }
   printf("FOO=[%s] BAR=[%s]\n", FOO, BAR);
}

Then ./nob FOO=69 rebuilds with -DFOO="69" (or /DFOO="69" if cl.exe — not tested) unless already defined as "69". It also works with ./nob FOO=69 BAR=96 but recompiles twice if both values are new. ./nob FOO=69 FOO=96 enters an infinte recompile loop and deletes itself (Go Delete Urself™).

[sqaxomonophonen]

I made it X-macro friendlier so it's possible to avoid a lot of config key duplication:

#define NOB_IMPLEMENTATION
#include "nob.h"

#ifndef FOO
#define FOO "default FOO"
#endif

#ifndef BAR
#define BAR "default BAR"
#endif

#define EMIT_CONFIGS \
   X(FOO) \
   X(BAR)

int main(int argc, char **argv)
{
   #define X(x) nob_go_define(#x, x);
   EMIT_CONFIGS
   #undef X
   NOB_GO_REBUILD_URSELF(argc, argv);
   for (int i=1; i<argc; ++i) {
      char* arg = argv[i];
      #define X(x) if (strlen(argv[i]) >= (1+strlen(#x)) && 0 == memcmp(arg, #x "=", (1+strlen(#x)))) NOB_GO_REDEFINE_STR(#x, arg+1+strlen(#x));
      EMIT_CONFIGS
      #undef X
   }
   #define X(x) printf("%s=\"%s\"\n", #x, x);
   EMIT_CONFIGS
   #undef X
   return 0;
}