includes/type: Added arbitrarily formattable type

includes/type/fmt.pat

@@ -0,0 +1,42 @@
+#pragma once
+
+import std.io;
+
+/*!
+    Type that allows specifying its format value using a format string.
+    ## Usage
+
+    The following code reads a u32 from the data and formats it as an upper case hexadecimal value with
+    a minimum of 8 digits which is prefixed by 0x.
+
+    The format string is the same as passed to `std::format()` and follows the libfmt specification.
+
+    ```rust
+        type::Formatted<u32, "0x{:08X}"> hex_formatted_integer @ 0x00;
+    ```
+*/
+
+namespace auto type {
+
+    /**
+        Arbitrarily formatted type
+        @tparam T Type to format
+        @tparam FormatString libfmt format string to format the value
+    */
+    struct Formatted<T, auto FormatString> {
+        T value;
+    } [[sealed, format("type::impl::format_formatted"), transform("type::impl::transform_formatted")]];
+
+    namespace impl {
+
+        fn format_formatted(ref auto formatted) {
+            return std::format(std::format("{{0:{}}}", formatted.FormatString), formatted.value);
+        };
+
+        fn transform_formatted(ref auto formatted) {
+            return formatted.value;
+        };
+
+    }
+
+}