nxt.array_traits source code

1 module nxt.array_traits;
2 
3 /// Is `true` iff `T` is a slice of `char`s.
4 enum isCharArray(T) = (is(T : const(char)[]));
5 
6 ///
7 @safe pure unittest
8 {
9     static assert(isCharArray!(char[]));
10     static assert(isCharArray!(const(char[])));
11     static assert(isCharArray!(const char[]));
12     static assert(isCharArray!(const const(char)[]));
13 
14     static assert(!isCharArray!(wstring));
15     static assert(!isCharArray!(dstring));
16 }
17 
18 /** Is `true` iff all `Ts` are slices with same unqualified matching element types.
19  *
20  * Used to define template-restrictions on template parameters of only arrays
21  * (slices) of the same unqualified element types.
22  */
23 template isSameSlices(Ts...)
24 if (Ts.length >= 2)
25 {
26     enum isSlice(T) = is(T : const(E)[], E);
27     enum isSliceOf(T, E) = is(T : const(E)[]);
28     static if (isSlice!(Ts[0]))
29     {
30         alias E = typeof(Ts[0].init[0]);
31         static foreach (T; Ts[1 .. $])
32         {
33             static if (is(typeof(isSameSlices) == void) && // not yet defined
34                        !(isSliceOf!(T, E)))
35             {
36                 enum isSameSlices = false;
37             }
38         }
39         static if (is(typeof(isSameSlices) == void)) // if not yet defined
40         {
41             enum isSameSlices = true;
42         }
43     }
44     else
45     {
46         enum isSameSlices = false;
47     }
48 }
49 
50 ///
51 @safe pure unittest
52 {
53     static assert(isSameSlices!(int[], int[]));
54     static assert(isSameSlices!(const(int)[], int[]));
55     static assert(isSameSlices!(int[], const(int)[]));
56     static assert(isSameSlices!(int[], immutable(int)[]));
57 
58     static assert(isSameSlices!(int[], int[], int[]));
59     static assert(isSameSlices!(int[], const(int)[], int[]));
60     static assert(isSameSlices!(int[], const(int)[], immutable(int)[]));
61     static assert(isSameSlices!(const(int)[], const(int)[], const(int)[]));
62 
63     static assert(!isSameSlices!(int, char));
64     static assert(!isSameSlices!(int, const(char)));
65     static assert(!isSameSlices!(int, int));
66 
67     static assert(!isSameSlices!(int[], char[]));
68     static assert(!isSameSlices!(int[], char[], char[]));
69     static assert(!isSameSlices!(char[], int[]));
70 
71     static assert(!isSameSlices!(char[], dchar[]));
72     static assert(!isSameSlices!(wchar[], dchar[]));
73     static assert(!isSameSlices!(char[], wchar[]));
74 }