rxd.meta2.switch_n source code

1 ///
2 module rxd.meta2.switch_n;
3 
4 import std.format : format;
5 
6 ///
7 enum switch2(string pred, string action1, string action2) =
8 q{
9     static if (__traits(compiles, { enum b = %1$s; } ))
10     {
11         static if (%1$s)
12             %2$s
13         else
14             %3$s
15     }
16     else
17     {
18         if (%1$s)
19             %2$s
20         else
21             %3$s
22     }
23 }.format(pred, action1, action2);
24 
25 ///
26 unittest
27 {
28     static assert (switch2!("val", "return 1;", "return 2;") ==
29     q{
30     static if (__traits(compiles, { enum b = val; } ))
31     {
32         static if (val)
33             return 1;
34         else
35             return 2;
36     }
37     else
38     {
39         if (val)
40             return 1;
41         else
42             return 2;
43     }
44 });
45 
46 }
47 
48 ///
49 enum switch3(string pred, string action1, string action2, string action3) =
50 q{
51     static if (__traits(compiles, { enum b = %1$s; } ))
52     {
53         static if (%1$s)
54             %2$s
55         else
56             %3$s
57     }
58     else
59     {
60         %4$s
61     }
62 }.format(pred, action1, action2, action3);
63 
64 ///
65 unittest
66 {
67     int func(bool val)
68     {
69         mixin (switch3!("val", "return 1;", "return 2;", "return 3;"));
70     }
71 
72     assert (func(true) == 3);
73     assert (func(false) == 3);
74 
75     int func2(bool val)()
76     {
77         mixin (switch3!("val", "return 1;", "return 2;", "return 3;"));
78     }
79 
80     assert (func2!true == 1);
81     assert (func2!false == 2);
82 }
83 
84 
85 ///
86 enum switch4(string pred, string do1, string do2, string do3, string do4) =
87 q{
88     static if (__traits(compiles, { enum b = %1$s; } ))
89     {
90         static if (%1$s)
91             %2$s
92         else
93             %3$s
94     }
95     else
96     {
97         if (%1$s)
98             %4$s
99         else
100             %5$s
101     }
102 }.format(pred, do1, do2, do3, do4);
103 
104 ///
105 unittest
106 {
107     int func(bool val)
108     {
109         mixin (switch4!("val",
110                     "return 1;", "return 2;",
111                     "return 3;", "return 4;"));
112     }
113 
114     assert (func(true) == 3);
115     assert (func(false) == 4);
116 
117     int func2(bool val)()
118     {
119         mixin (switch4!("val",
120                     "return 1;", "return 2;",
121                     "return 3;", "return 4;"));
122     }
123 
124     assert (func2!true == 1);
125     assert (func2!false == 2);
126 }
127