diff --git a/app.cpp b/app.cpp
index 6087bdf..654a0bd 100644
--- a/app.cpp
+++ b/app.cpp
@@ -1,4 +1,3 @@
-#include <stdio.h>
 #include "core.c"
 
 int main(int argc, char **argv) {
@@ -6,7 +5,8 @@ int main(int argc, char **argv) {
     Arena *arena = arenaAlloc(Megabytes(64));
     StringList args = getArgs(arena, argc, argv);
 
-    print("%S", strSplit(arena, s("-"), s("hallo-world")));
+    printStrList(args);
+    printStrList(strSplit(arena, s("-"), s("the-quick-brown-fox-jumps-over-the-lazy-dog")));
 
     return 0;
 }
diff --git a/core.c b/core.c
index 16c1665..5074967 100644
--- a/core.c
+++ b/core.c
@@ -210,7 +210,8 @@ StringList strSplit(Arena *arena, string splitStr, string inputStr) {
         size_t start = 0;
         void *beginning = (char *)arena->memory + arena->head;
         while (c < inputStr.length - splitStr.length) {
-            if (strEql(strSlice(inputStr, c, c + splitStr.length), splitStr)) {
+            string mystr = strSlice(inputStr, c, c + splitStr.length);
+            if (strEql(mystr, splitStr)) {
                 string *splitString = PushStruct(arena, string);
                 splitString->str = inputStr.str + start;
                 splitString->length = c - start;
@@ -224,9 +225,10 @@ StringList strSplit(Arena *arena, string splitStr, string inputStr) {
         splitString->str = inputStr.str + start;
         splitString->length = inputStr.length - start;
         splitCount++;
-        result.data = (string *)beginning,
-        result.head = splitCount,
+
+        result.data = (string *)beginning;
         result.length = splitCount;
+        result.head = splitCount;
     }
     return result;
 }
@@ -293,7 +295,7 @@ ParsePositiveReal32Result parsePositiveReal32(string str, size_t *lengthPointer)
 StringList getArgs(Arena *arena, int argc, char **argv) {
     StringList args = PushList(arena, StringList, (size_t)argc - 1);
     for (int i = 1; i < argc; i++) {
-        AppendList(string, &args, strFromCString(arena, argv[i]));
+        AppendList(&args, strFromCString(arena, argv[i]));
     }
     return args;
 }
@@ -354,12 +356,8 @@ function void printStdout(const char *fmt, ...) {
     va_end(argList);
 }
 
-void print(const char *fmt, ...) {
-    va_list argList;
-    va_start(argList, fmt);
-    os_print(StdStream_stdout, fmt, argList);
-    va_end(argList);
-}
+void (*print)(const char *fmt, ...) = &printStdout;
+#define SetStdErr() DeferLoop(print = &printStderr, print = &printStdout)
 
 // TODO(dledda): mat print functions
 /*
@@ -400,27 +398,26 @@ void print(list<Vector2<real32>> l, StdStream target) {
 }
 */
 
-void (*__djstdlib_logFn)(const char *fmt, ...) = &printStdout;
 void printIntList(IntList l) {
-    __djstdlib_logFn("{ ");
+    print("{ ");
     for (size_t i = 0; i < l.length; i++) {
         if (i != 0) {
-            __djstdlib_logFn(", ");
+            print(", ");
         }
-        __djstdlib_logFn("%i", l.data[i]);
+        print("%i", l.data[i]);
     }
-    __djstdlib_logFn(" } length: %zu, head: %zu\n", l.length, l.head);
+    print(" } length: %zu, head: %zu\n", l.length, l.head);
 }
 
-void printStringList(StringList l) {
-    __djstdlib_logFn("{ ");
+void printStrList(StringList l) {
+    print("{ ");
     for (size_t i = 0; i < l.length; i++) {
         if (i != 0) {
-            __djstdlib_logFn(", ");
-        } 
-        __djstdlib_logFn("\"%S\"", l.data[i]);
+            print(", ");
+        }
+        print("\"%S\"", l.data[i]);
     }
-    __djstdlib_logFn(" } length: %zu, head: %zu\n", l.length, l.head);
+    print(" } length: %zu, head: %zu\n", l.length, l.head);
 }
 
 int intCompare(const void *a, const void *b) {
diff --git a/core.h b/core.h
index b806ffd..54b8fb8 100644
--- a/core.h
+++ b/core.h
@@ -45,8 +45,10 @@ typedef struct string string;
 #define Billion(n)  ((n)*1000000000LL)
 
 #define ArrayCount(arr) (sizeof(arr) / sizeof((arr)[0]))
-#define MemberSize(type, memberName) (sizeof(((type*)0)->data))
-#define MemberSizeUnderlying(type, memberName) (sizeof(*((type*)0)->data))
+#define MemberSize(type, memberName) sizeof(((type *)0)->memberName)
+#define MemberType(type, memberName) typeof(((type *)0)->memberName)
+#define MemberSizeUnderlying(type, memberName) sizeof(*((type *)0)->memberName)
+#define MemberTypeUnderlying(type, memberName) typeof(*((type *)0)->memberName)
 
 // ### Arenas ###
 typedef struct {
@@ -142,14 +144,14 @@ inline function Vec4 vec4(real32 x, real32 y, real32 z, real32 w) {
 
 DefineList(string, String);
 
-#define PushList(arena, type, size) ((type){ pushSize(arena, MemberSizeUnderlying(type, data)), size, 0 })
-#define EmptyList(type) ((type){ NULL, 0, 0 })
-#define PushListZero(arena, type, size) ((type){ pushSizeFill(arena, MemberSizeUnderlying(type, data), 0), size, 0 })
-#define PushFullList(arena, type, size) ((type){ pushSize(arena, MemberSizeUnderlying(type, data)), size, size })
-#define PushFullListZero(arena, type, size) ((type){ pushSizeFill(arena, MemberSizeUnderlying(type, data), 0), size, size })
-#define ArrayAsList(type, array) ((type){ array, ArrayCount(array), ArrayCount(array) })
+#define PushList(arena, type, size) (type){ (MemberTypeUnderlying(type, data) *)pushSize(arena, MemberSizeUnderlying(type, data)*size), size, 0 }
+#define EmptyList(type) (type){ NULL, 0, 0 }
+#define PushListZero(arena, type, size) (type){ (MemberTypeUnderlying(type, data) *)pushSizeFill(arena, MemberSizeUnderlying(type, data)*size, 0), size, 0 }
+#define PushFullList(arena, type, size) (type){ (MemberTypeUnderlying(type, data) *)pushSize(arena, MemberSizeUnderlying(type, data))*size, size, size }
+#define PushFullListZero(arena, type, size) (type){ (MemberTypeUnderlying(type, data) *)pushSizeFill(arena, MemberSizeUnderlying(type, data)*size, 0), size, size }
+#define ArrayAsList(type, array) (type){ array, ArrayCount(array), ArrayCount(array) }
 
-#define AppendList(type, list, element) \
+#define AppendList(list, element) \
     if ((list)->head < (list)->length) { \
         (list)->data[(list)->head++] = (element); \
     }
@@ -264,12 +266,10 @@ typedef enum {
 #define COLOR_TEXT_FG_BG(text, foregroundcolor, backgroundcolor) ANSI_INSTRUCTION_FROM_ENUM(foregroundcolor) ANSI_INSTRUCTION_FROM_ENUM(backgroundcolor) text  ANSI_RESET
 #define COLOR_TEXT_RGB(text, red, green, blue) ANSI_INSTRUCTION_STR("38;2;" #red ";" #green ";" #blue) text ANSI_RESET
 
-#define SetStdErr() DeferLoop
 DefineList(int, Int);
-void printIntListErr(IntList l);
-void printStrListErr(StringList l);
-void print(const char *fmt, ...);
-void printErr(const char *fmt, ...);
+void printIntList(IntList l);
+void printStrList(StringList l);
+extern void (*print)(const char *fmt, ...);
 
 // ### Loops ###
 #define EachIn(list, it) size_t it = 0; it < (list).head; it++