:sparkles: (Janet) chapter 9

Janet/chapter9/main.janet

···
+(import set)
+
+(set/hello)

Janet/chapter9/project.janet

···
+(declare-project :name "set")
+
+(declare-native
+ :name "set"
+ :source ["set.c"])

Janet/chapter9/set.c

···
+#include <janet.h>
+
+static Janet cfun_hello(int32_t argc, Janet *argv) {
+  janet_fixarity(argc, 0);
+  printf("hello world\n");
+  return janet_wrap_nil();
+}
+
+static JanetReg cfuns[] = {
+  {"hello", cfun_hello, "(hello)\n\nprints hello"},
+  {NULL, NULL, NULL}
+};
+
+JANET_MODULE_ENTRY(JanetTable *env) {
+  janet_cfuns(env, "set", cfuns);
+}