Change nu_dup to return a mutable slice copy.

source/numem/core/memory.d

@@ -229,6 +229,9 @@ T[] nu_reverse(T)(auto ref T[] range) @nogc nothrow {
 /**
     Creates a shallow duplicate of the given buffer.
 
+    `nu_dup` is preserving the constness qualifiers. 
+    If you're looking for a mutable duplicate, see also `nu_mdup`.
+
     Params:
         buffer = Buffer to duplicate.
 
@@ -267,6 +270,25 @@ immutable(T)[] nu_idup(T)(inout(T)[] buffer) @trusted @nogc nothrow pure {
     return cast(immutable(T)[])nu_dup(buffer);
 }
 
+/**
+    Creates a shallow mutable duplicate of the given buffer.
+
+    Params:
+        buffer = Buffer to duplicate.
+
+    Memorysafety:
+        This function copies data out of the slice into a new
+        memory allocation; as such it has to be freed.
+        It is otherwise safe, in that it won't modify
+        the original memory provided.
+
+    Returns:
+        Duplicated slice, must be freed with $(D nu_resize)
+*/
+T[] nu_mdup(T)(inout(T)[] buffer) @trusted @nogc nothrow pure {
+    return cast(T[])nu_dup(buffer);
+}
+
 /**
     Gets the retain function for type T and calls it.
 */

tests/ut/core/memory.d

@@ -11,11 +11,14 @@ unittest {
 
 @("nu_dup")
 unittest {
+    char[] str0 = "Hello, world!".nu_mdup();
     const(char)[] str1 = "Hello, world!".nu_dup();
     immutable(char)[] str2 = "Hello, world!".nu_idup();
+    assert(str0 == "Hello, world!");
     assert(str1 == "Hello, world!");
     assert(str2 == "Hello, world!");
 
+    assert(!str0.nu_resize(0).ptr);
     assert(!str1.nu_resize(0).ptr);
     assert(!str2.nu_resize(0).ptr);
 }