diff --git a/lithos_c/inc/Lth_stdlib.h b/lithos_c/inc/Lth_stdlib.h
index bbbd9a9..d8242d2 100644
--- a/lithos_c/inc/Lth_stdlib.h
+++ b/lithos_c/inc/Lth_stdlib.h
@@ -13,9 +13,14 @@
 #ifndef lithos3__Lth_stdlib_h
 #define lithos3__Lth_stdlib_h
 
+#include <stdbool.h>
+
 #define Lth_isidenti(ch) \
    (isalpha(ch) || isdigit(ch) || ch == '_' || ch == '$' || ch == '\'')
 
+// Post-for. Sort of.
+#define Lth_pfor(cond, expr) while((cond) && ((expr), true))
+
 
 // Extern Functions ----------------------------------------------------------|