24 lines
1.4 KiB
ReStructuredText
24 lines
1.4 KiB
ReStructuredText
as_container
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============
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*force a type to be viewed as a container-type when serialized to Lua*
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.. code-block:: cpp
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template <typename T>
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struct as_returns_t { ... };
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template <typename T>
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as_returns_t<T> as_returns( T&& );
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Sometimes, you have a type whose metatable you claim with a usertype metatable via :doc:`usertype semantics<usertype>`. But, it still has parts of it that make it behave like a container in C++: A ``value_type`` typedef, an ``iterator`` typedef, a ``begin``, an ``end``, and other things that satisfy the `Container requirements`_ or the `Sequence Container requirements`_ or behaves like a `forward_list`_.
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Whatever the case is, you need it to be returned to Lua and have many of the traits and functionality described in the :doc:`containers documentation<../containers>`. Wrap a return type or a setter in ``sol::as_container( value );`` to allow for a type to be treated like a container, regardless of whether ``sol::is_container`` triggers or not.
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See `this container example`_ to see how it works.
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.. _this container example: https://github.com/ThePhD/sol2/blob/develop/examples/source/container_usertype_as_container.cpp
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.. _Container requirements: http://en.cppreference.com/w/cpp/concept/Container
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.. _Sequence Container requirements: http://en.cppreference.com/w/cpp/concept/SequenceContainer
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.. _forward_list: http://en.cppreference.com/w/cpp/container/forward_list
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