diff --git a/src/libcore/os.rs b/src/libcore/os.rs
index d01f45928302ef08624ae9ed2b78c64aa5c689ba..0045bad07a563903567aca11b9f744c2412fa6fa 100644
--- a/src/libcore/os.rs
+++ b/src/libcore/os.rs
@@ -732,6 +732,30 @@ pub fn set_exit_status(code: int) {
     rustrt::rust_set_exit_status(code as libc::intptr_t);
 }
 
+/**
+ * Returns the command line arguments
+ *
+ * Returns a list of the command line arguments.
+ */
+#[cfg(target_os = "macos")]
+pub fn args() -> ~[~str] {
+    unsafe {
+        let (argc, argv) = (*_NSGetArgc() as uint, *_NSGetArgv());
+        let mut args = ~[];
+        for uint::range(0, argc) |i| {
+            vec::push(&mut args, str::raw::from_c_str(*argv.offset(i)));
+        }
+        return args;
+    }
+}
+
+#[cfg(target_os = "macos")]
+extern {
+    // These functions are in crt_externs.h.
+    pub fn _NSGetArgc() -> *c_int;
+    pub fn _NSGetArgv() -> ***c_char;
+}
+
 #[cfg(unix)]
 pub fn family() -> ~str { ~"unix" }
 
diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs
index d0b848adde24adf86288456f0f4021ce6decda9e..9f9d2eea0e67a8d768ce9972c105e6f43f66538d 100644
--- a/src/libcore/ptr.rs
+++ b/src/libcore/ptr.rs
@@ -47,7 +47,7 @@ pub mod p2 {
 
 /// Calculate the offset from a pointer
 #[inline(always)]
-pub fn offset<T>(ptr: *T, count: uint) -> *T {
+pub pure fn offset<T>(ptr: *T, count: uint) -> *T {
     unsafe {
         (ptr as uint + count * sys::size_of::<T>()) as *T
     }
@@ -55,7 +55,7 @@ pub fn offset<T>(ptr: *T, count: uint) -> *T {
 
 /// Calculate the offset from a const pointer
 #[inline(always)]
-pub fn const_offset<T>(ptr: *const T, count: uint) -> *const T {
+pub pure fn const_offset<T>(ptr: *const T, count: uint) -> *const T {
     unsafe {
         (ptr as uint + count * sys::size_of::<T>()) as *T
     }
@@ -63,7 +63,7 @@ pub fn const_offset<T>(ptr: *const T, count: uint) -> *const T {
 
 /// Calculate the offset from a mut pointer
 #[inline(always)]
-pub fn mut_offset<T>(ptr: *mut T, count: uint) -> *mut T {
+pub pure fn mut_offset<T>(ptr: *mut T, count: uint) -> *mut T {
     (ptr as uint + count * sys::size_of::<T>()) as *mut T
 }
 
@@ -176,18 +176,25 @@ pub fn ref_eq<T>(thing: &a/T, other: &b/T) -> bool {
     to_uint(thing) == to_uint(other)
 }
 
-pub trait Ptr {
+pub trait Ptr<T> {
     pure fn is_null() -> bool;
     pure fn is_not_null() -> bool;
+    pure fn offset(count: uint) -> self;
 }
 
 /// Extension methods for pointers
-impl<T> *T: Ptr {
+impl<T> *T: Ptr<T> {
     /// Returns true if the pointer is equal to the null pointer.
+    #[inline(always)]
     pure fn is_null() -> bool { is_null(self) }
 
     /// Returns true if the pointer is not equal to the null pointer.
+    #[inline(always)]
     pure fn is_not_null() -> bool { is_not_null(self) }
+
+    /// Calculates the offset from a pointer.
+    #[inline(always)]
+    pure fn offset(count: uint) -> *T { offset(self, count) }
 }
 
 // Equality for pointers