diff options
Diffstat (limited to 'indra/llcommon/llmake.h')
-rw-r--r-- | indra/llcommon/llmake.h | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/indra/llcommon/llmake.h b/indra/llcommon/llmake.h new file mode 100644 index 0000000000..9a662a0640 --- /dev/null +++ b/indra/llcommon/llmake.h @@ -0,0 +1,63 @@ +/** + * @file llmake.h + * @author Nat Goodspeed + * @date 2015-12-18 + * @brief Generic llmake<Template>(arg) function to instantiate + * Template<decltype(arg)>(arg). + * + * Many of our class templates have an accompanying helper function to + * make an instance with arguments of arbitrary type. llmake() + * eliminates the need to declare a new helper function for every such + * class template. + * + * also relevant: + * + * Template parameter deduction for constructors + * http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0091r0.html + * + * https://github.com/viboes/std-make + * + * but obviously we're not there yet. + * + * $LicenseInfo:firstyear=2015&license=viewerlgpl$ + * Copyright (c) 2015, Linden Research, Inc. + * $/LicenseInfo$ + */ + +#if ! defined(LL_LLMAKE_H) +#define LL_LLMAKE_H + +/*==========================================================================*| +// When we allow ourselves to compile with C++11 features enabled, this form +// should generically handle an arbitrary number of arguments. + +template <template<typename...> class CLASS_TEMPLATE, typename... ARGS> +CLASS_TEMPLATE<ARGS...> llmake(ARGS && ... args) +{ + return CLASS_TEMPLATE<ARGS...>(std::forward<ARGS>(args)...); +} +|*==========================================================================*/ + +// As of 2015-12-18, this is what we'll use instead. Add explicit overloads +// for different numbers of template parameters as use cases arise. + +/** + * Usage: llmake<SomeTemplate>(arg) + * + * Deduces the type T of 'arg' and returns an instance of SomeTemplate<T> + * initialized with 'arg'. Assumes a constructor accepting T (by value, + * reference or whatever). + */ +template <template<typename> class CLASS_TEMPLATE, typename ARG1> +CLASS_TEMPLATE<ARG1> llmake(const ARG1& arg1) +{ + return CLASS_TEMPLATE<ARG1>(arg1); +} + +template <template<typename, typename> class CLASS_TEMPLATE, typename ARG1, typename ARG2> +CLASS_TEMPLATE<ARG1, ARG2> llmake(const ARG1& arg1, const ARG2& arg2) +{ + return CLASS_TEMPLATE<ARG1, ARG2>(arg1, arg2); +} + +#endif /* ! defined(LL_LLMAKE_H) */ |