Add a lua demo

Author: ebraminio

fontconfig-resolve.c

@@ -0,0 +1,38 @@
+// cc fontconfig-resolve.c `pkg-config --libs --cflags fontconfig` -Wall && ./a.out
+// https://gist.github.com/CallumDev/7c66b3f9cf7a876ef75f#gistcomment-3355764
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <fontconfig/fontconfig.h>
+
+int main() {
+  FcInit();
+  FcConfig *config = FcInitLoadConfigAndFonts();
+
+  // not necessarily has to be a specific name
+  FcPattern *pat = FcNameParse((const FcChar8 *)"Arial");
+
+  // NECESSARY; it increases the scope of possible fonts
+  FcConfigSubstitute(config, pat, FcMatchPattern);
+  // NECESSARY; it increases the scope of possible fonts
+  FcDefaultSubstitute(pat);
+
+  char *fontFile;
+  FcResult result;
+
+  FcPattern *font = FcFontMatch(config, pat, &result);
+
+  if (font) {
+    FcChar8 *file = NULL;
+
+    if (FcPatternGetString(font, FC_FILE, 0, &file) == FcResultMatch) {
+      fontFile = (char *)file;
+      printf("%s\n", fontFile);
+    }
+  }
+  FcPatternDestroy(font);
+  FcPatternDestroy(pat);
+  FcConfigDestroy(config);
+  FcFini();
+  return 0;
+}

lua-run.c

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+// clang lua-run.c `pkg-config --libs --cflags lua` -Wall && ./a.out
+// https://lucasklassmann.com/blog/2019-02-02-how-to-embeddeding-lua-in-c/
+#include <lauxlib.h>
+#include <lua.h>
+#include <lualib.h>
+
+int multiplication(lua_State *L) {
+  int a = luaL_checkinteger(L, 1);
+  int b = luaL_checkinteger(L, 2);
+  lua_Integer c = a * b;
+  lua_pushinteger(L, c);
+  return 1;
+}
+
+int main(int argc, char **argv) {
+  lua_State *L = luaL_newstate();
+  luaL_openlibs(L);
+  lua_newtable(L);
+  const struct luaL_Reg my_functions_registery[] = {{"mul", multiplication}};
+  // put the registry on the stack
+  luaL_setfuncs(L, my_functions_registery, 0);
+  // set it to my_functions_registry
+  lua_setglobal(L, "my_functions_registry");
+  char *code = "print(my_functions_registry.mul(7, 8))";
+
+  if (luaL_loadstring(L, code) == LUA_OK) {
+    if (lua_pcall(L, 0, 1, 0) == LUA_OK) {
+      lua_pop(L, lua_gettop(L));
+    }
+  }
+
+  lua_close(L);
+  return 0;
+}