diff --git a/.clangd b/.clangd
index 659449b..65215ff 100644
--- a/.clangd
+++ b/.clangd
@@ -1,4 +1,5 @@
 CompileFlags:
   Add:
-    - [-std=c99, -xc]
+    - -std=c99
+    - -xc
     - -DOS_LINUX
diff --git a/app.cpp b/app.c
similarity index 93%
rename from app.cpp
rename to app.c
index 654a0bd..83871bf 100644
--- a/app.cpp
+++ b/app.c
@@ -5,6 +5,7 @@ int main(int argc, char **argv) {
     Arena *arena = arenaAlloc(Megabytes(64));
     StringList args = getArgs(arena, argc, argv);
 
+    print("Args:\n");
     printStrList(args);
     printStrList(strSplit(arena, s("-"), s("the-quick-brown-fox-jumps-over-the-lazy-dog")));
 
diff --git a/build b/build
old mode 100644
new mode 100755
index 5601ac6..fb7fa2f
--- a/build
+++ b/build
@@ -1,3 +1,7 @@
 #!/bin/bash
 
-g++ -g -g3 -lm -DOS_LINUX=1 -DENABLE_ASSERT=1 ./app.cpp -o ./target/app
+clang -g -g3 -lm -DOS_LINUX=1 -DENABLE_ASSERT=1 ./app.c -o ./target/app
+
+if [[ $1 == "run" ]] then
+    ./target/app
+fi
diff --git a/core.c b/core.c
index 5074967..09d9a3a 100644
--- a/core.c
+++ b/core.c
@@ -1,6 +1,6 @@
 #include "os.c"
 #include "math.h"
-#include "string.h" // memmove
+#include "string.h" // for memmove
 #include "core.h"
 #define STB_SPRINTF_IMPLEMENTATION
 #include "vendor/stb_sprintf.h"
@@ -165,8 +165,6 @@ string strPrintf(Arena *arena, const char *fmt, ...) {
     return result;
 }
 
-#define ListSlice(__ls_list__, __ls_start__, __ls_stop__) (__ls_stop__ > l.head || __ls_start__ > __ls_stop__ ? {0} : { l.data + start, stop - start, stop - start, })
-
 string strSlice(string str, size_t start, size_t stop) {
     if (stop == 0) {
         stop = str.length;
@@ -228,7 +226,7 @@ StringList strSplit(Arena *arena, string splitStr, string inputStr) {
 
         result.data = (string *)beginning;
         result.length = splitCount;
-        result.head = splitCount;
+        result.capacity = splitCount;
     }
     return result;
 }
@@ -247,14 +245,14 @@ ParsePositiveIntResult parsePositiveInt(string str, size_t *lengthPointer) {
             result *= 10;
             result += str.str[i] - '0';
         }
-        return (ParsePositiveIntResult){ result, true };
+        return (ParsePositiveIntResult){ .result=result, .valid=true };
     } else {
-        return (ParsePositiveIntResult){0, false};
+        return (ParsePositiveIntResult){ .result=0, .valid=false};
     }
 }
 
 ParsePositiveReal32Result parsePositiveReal32(string str, size_t *lengthPointer) {
-    ParsePositiveReal32Result result = {NAN, false};
+    ParsePositiveReal32Result result = { .result=NAN, .valid=false};
 
     string wholePartStr = (string){0};
     string fractionalPartStr = (string){0};
@@ -307,9 +305,8 @@ UnixTimestamp getSystemUnixTime() {
 }
 
 Timestamp timestampFromUnixTime(UnixTimestamp *unixTimestamp) {
-    struct tm timestamp = {0};
-    gmtime_r((time_t *)unixTimestamp, &timestamp);
-    return timestamp;
+    struct tm *timestamp = gmtime((time_t *)unixTimestamp);
+    return *timestamp;
 }
 
 string formatTimeHmsUnix(Arena *arena, UnixTimestamp time) {
@@ -406,7 +403,7 @@ void printIntList(IntList l) {
         }
         print("%i", l.data[i]);
     }
-    print(" } length: %zu, head: %zu\n", l.length, l.head);
+    print(" } length: %zu, capacity: %zu\n", l.length, l.capacity);
 }
 
 void printStrList(StringList l) {
@@ -417,7 +414,7 @@ void printStrList(StringList l) {
         }
         print("\"%S\"", l.data[i]);
     }
-    print(" } length: %zu, head: %zu\n", l.length, l.head);
+    print(" } length: %zu, capacity: %zu\n", l.length, l.capacity);
 }
 
 int intCompare(const void *a, const void *b) {
diff --git a/core.h b/core.h
index 54b8fb8..cff6ef9 100644
--- a/core.h
+++ b/core.h
@@ -2,10 +2,8 @@
 #define CORE_H
 
 // cstdlib includes
-#include "math.h"
 #include "stdbool.h"
 #include "stdint.h" // necessary for int type sizes
-#include "stdio.h"
 #include "time.h" // TODO(djledda): try not to depend on this one
 
 // ### Misc macros ###
@@ -139,7 +137,7 @@ inline function Vec4 vec4(real32 x, real32 y, real32 z, real32 w) {
     typedef struct {\
         type* data;\
         size_t length;\
-        size_t head;\
+        size_t capacity;\
     } prefix ## List
 
 DefineList(string, String);
@@ -152,12 +150,14 @@ DefineList(string, String);
 #define ArrayAsList(type, array) (type){ array, ArrayCount(array), ArrayCount(array) }
 
 #define AppendList(list, element) \
-    if ((list)->head < (list)->length) { \
-        (list)->data[(list)->head++] = (element); \
+    if ((list)->length < (list)->capacity) { \
+        (list)->data[(list)->length++] = (element); \
     }
-#define ZeroListFull(list) memset((list)->data, 0, (list)->head * sizeof(T))
-#define ZeroList(list) (list)->head = 0; \
-    memset((list)->data, 0, (list)->head * sizeof(T));
+#define ZeroListFull(list) memset((list)->data, 0, (list)->length * sizeof(T))
+#define ZeroList(list) (list)->length = 0; \
+    memset((list)->data, 0, (list)->length * sizeof(T));
+#define ListSlice(list, start, stop) (stop > list.length || start > stop ? {0} : { list.data + start, stop - start, stop - start, })
+#define ListTail(list, start) ListSlice(list, list.length)
 
 // ### Strings ###
 struct string {
@@ -189,9 +189,16 @@ StringList strSplit(Arena *arena, string splitStr, string inputStr);
 string strPrintfv(Arena *arena, const char *fmt, va_list args);
 string strPrintf(Arena *arena, const char *fmt, ...);
 
-typedef struct { uint8 result; bool valid; } ParsePositiveIntResult;
+typedef struct {
+    uint8 result;
+    bool valid;
+} ParsePositiveIntResult;
 ParsePositiveIntResult parsePositiveInt(string str, size_t *lengthPointer);
-typedef struct { real32 result; bool valid; } ParsePositiveReal32Result;
+
+typedef struct {
+    real32 result;
+    bool valid;
+} ParsePositiveReal32Result;
 ParsePositiveReal32Result parsePositiveReal32(string str, size_t *lengthPointer);
 
 inline function bool isNumeric(char c);
@@ -272,8 +279,8 @@ void printStrList(StringList l);
 extern void (*print)(const char *fmt, ...);
 
 // ### Loops ###
-#define EachIn(list, it) size_t it = 0; it < (list).head; it++
-#define EachInReversed(list, it) size_t it = (list).head - 1; it >= 0 && it < (list).head; it--
+#define EachIn(list, it) size_t it = 0; it < (list).length; it++
+#define EachInReversed(list, it) size_t it = (list).length - 1; it >= 0 && it < (list).length; it--
 #define EachInArray(arr, it)  size_t it = 0; it < ArrayCount(arr); ++it
 
 // ### Misc ###
diff --git a/os_linux.c b/os_linux.c
index 8da939a..8b2897b 100644
--- a/os_linux.c
+++ b/os_linux.c
@@ -5,7 +5,8 @@
 
 #include "sys/mman.h"
 #include "sys/stat.h"
-#include "unistd.h"
+#include "unistd.h" // POSIX Standard
+#include "stdio.h"
 
 void *os_alloc(size_t capacity) {
     return mmap(0, capacity, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
@@ -78,14 +79,14 @@ void os_print(StdStream target, const char *fmt, va_list argList) {
     string result = strPrintfv(temp.arena, fmt, argList);
     // TODO(djledda): finish implementation without cstdlib
     switch (target) {
-        case StdStream_stdin: 
+        case StdStream_stdin:
             write(0, (const void *)result.str, result.length);
             break;
-        case StdStream_stderr: 
+        case StdStream_stderr:
             fflush(stderr);
             write(2, (const void *)result.str, result.length);
             break;
-        case StdStream_stdout: 
+        case StdStream_stdout:
         default:
             fflush(stdout);
             write(1, (const void *)result.str, result.length);