Result impl and example

main.c

@@ -6,3 +6,19 @@ fn(main(), int) {
    print("Hello, World!\n", a);
    Ok();
 }
+
+typedef const char *ErrString;
+typedef void *MemHandle;
+Result_impl(MemHandle, ErrString)
+Result_unwrap_impl(MemHandle, ErrString)
+fn (gimmy_memory(size_t n_bytes), Result(MemHandle, ErrString)){
+    Result(MemHandle, ErrString) possible =
+        {.is_valid = true, .data = malloc(n_bytes)};
+
+    if (!possible.data)
+    {
+        possible.is_valid = false;
+        possible.err = "memory allocation failure";
+    }
+    return possible;
+}

rust.h

@@ -1,6 +1,6 @@
 #include <stdbool.h>
 #include <stdio.h>
-
+#include <stdlib.h>
 
 #define fn(decl, type) type decl
 #define let(decl, type) const type decl
@@ -12,3 +12,24 @@
 #define Err(); return 1
 
 #define enum union
+
+// Rust like return impl
+#define Result_impl(T, E) \
+typedef struct { \
+    bool is_valid; \
+    union { \
+        T data; \
+        E err; \
+    }; \
+} Result_##T##_##E;
+
+#define Result(T, E) Result_##T##_##E
+
+#define Result_unwrap_impl(T, E) \
+T Result_##T##_unwrap (Result(T, E) result) { \
+    if (result.is_valid) \
+        return result.data; \
+\
+    fprintf(stderr, "%s\n", result.err); \
+    exit(1); \
+}