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    <p>Anyway there will be at once one switch if you will not use run-time polymorphism. If you will use static polymorphism than you need either specialization or switch. </p> <p>Its good approach to use type2enum and enum2type mapping:</p> <p>type2enum:</p> <pre><code>// preparition template&lt;class T&gt; type2enum(); #define TYPE2ENUM_SPEC(TYPE, ENUM) \ template&lt;&gt; type2enum&lt;TYPE&gt;() \ { return ENUM; } enum { T1enum, T2enum, T3enum } TYPE2ENUM_SPEC(type1_t, T1enum); TYPE2ENUM_SPEC(type2_t, T2enum); TYPE2ENUM_SPEC(some_third_type_t, T3enum); </code></pre> <p>and backward enum2type:</p> <pre><code>// preparition template&lt;int Enum&gt; struct enum2type; #define ENUM2TYPE_SPEC(ENUM, TYPE) \ template&lt;&gt; struct Enum2Type&lt;ENUM&gt; \ { typedef TYPE type_t; } // and generic macro #define CREATE_TYPE_MAPPING(TYPE, INTEGER) \ #define TYPE2ENUM_SPEC(TYPE, INTEGER) \ #define ENUM2TYPE_SPEC(INTEGER, TYPE) </code></pre> <p>and the sample of code:</p> <p>we have Type1, Type2, Type3 and enum:</p> <pre><code>enum {T1, T2, T3}; CREATE_TYPE_MAPPING(Type1, T1); CREATE_TYPE_MAPPING(Type2, T2); CREATE_TYPE_MAPPING(Type3, T3); </code></pre> <p>than use it for mapping type to enum:</p> <pre><code>int typeId = type2enum&lt;Type1&gt;(); </code></pre> <p>or constant enum to type:</p> <pre><code>typedef Enum2Type&lt;ConstEnumType&gt;::type_t some_t; </code></pre> <p>and for runtime enum to type you use something like:</p> <pre><code>template&lt;class ObjT&gt; void DoWithTypeIdValue(int enumValue, const ObjT&amp; obj) { switch(enumValue) { case enumType1: obj.do&lt;Enum2Type&lt;enumType1&gt;::type_t&gt;(); break; case enumType2: obj.do&lt;Enum2Type&lt;enumType2&gt;::type_t&gt;(); break; case enumType3: obj.do&lt;Enum2Type&lt;enumType3&gt;::type_t&gt;(); break; default: assert(!"Unknown type constant"); } } </code></pre>
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    1. POHow to do a typed parameter package class?
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    1. USSergei
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    1. COThis is exactly what I meant by "specializing for all types manually", and it is not what I wanted, even though this is what I ended up implementing. There was no satisfying way around it.
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      1. USFrigg
    2. COUnderstood. See next solution below.
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