diff --git a/SLS_C/SlsStr.md b/SLS_C/SlsStr.md
new file mode 100644
index 0000000..9353158
--- /dev/null
+++ b/SLS_C/SlsStr.md
@@ -0,0 +1,17 @@
+# Sls String
+*string.h*
+
+## Formats
+
+- `c` char\*
+- `d` int32_t
+- `l` int64_t
+- `ul` uint64_t
+- `zu` size_t
+- `f` double
+- `s` string.h SlsStr
+- `t` lexer.h TokenType
+- `a` lexer.h ArrayType
+- `i` lexer.h IntegerBuiltInType
+- `e` error.h SlsError
+- `b` bool.h Boolean
diff --git a/SLS_C/include/sls/string.h b/SLS_C/include/sls/string.h
index e068a0c..62d5a93 100644
--- a/SLS_C/include/sls/string.h
+++ b/SLS_C/include/sls/string.h
@@ -7,10 +7,22 @@
 #define SLS_STRING_H
 
 #include <stddef.h>
+#include <stdarg.h>
 
 #include "bool.h"
 
+typedef struct {
+    const size_t len;
+    const char *str;
+    const Boolean allocated;
+} SlsStr;
+
+#define SLS_STR(s) (SlsStr){ sizeof(s) - 1, (s), FALSE }
+
 int isascii(unsigned char c);
 size_t strnlen(const char *s, size_t maxlen);
 
+SlsStr malloc_str(const char *s, size_t maxlen);
+SlsStr format(const SlsStr s, ...);
+
 #endif // SLS_STRING_H
diff --git a/SLS_C/src/string.c b/SLS_C/src/string.c
index b7a86e3..cabfb91 100644
--- a/SLS_C/src/string.c
+++ b/SLS_C/src/string.c
@@ -5,6 +5,7 @@
 
 #include <stddef.h>
 #include <string.h>
+#include <stdarg.h>
 
 int isascii(unsigned char c) {
     return c < 128;
@@ -16,3 +17,10 @@ size_t strnlen(const char *s, size_t maxlen) {
         if (s[i] == '\0') break;
     return i;
 }
+
+char *malloc_str(const char *s, size_t maxlen) {
+    size_t length = strnlen(s, maxlen);
+    char *new_str = (char *)malloc(sizeof(char) * length);
+    strncpy(new_str, s, length);
+    return new_str;
+}