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72 lines
2.3 KiB
ReStructuredText
72 lines
2.3 KiB
ReStructuredText
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c_call
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======
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Templated type to transport functions through templates
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-------------------------------------------------------
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.. code-block:: cpp
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template <typename Function, Function f>
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int c_call (lua_State* L);
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template <typename... Functions>
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int c_call (lua_State* L);
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The goal of ``sol::c_call<...>`` is to provide a way to wrap a function and transport it through a compile-time context. This enables faster speed at the cost of a much harder to read / poorer interface. ``sol::c_call`` expects a type for its first template argument, and a value of the previously provided type for the second template argument. To make a compile-time transported overloaded function, specify multiple functions in the same ``type, value`` pairing, but put it inside of a ``sol::wrap``. Note that is can also be placed into the argument list for a :doc:`usertype<usertype>` as well.
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It is advisable for the user to consider making a macro to do the necessary ``decltype( &function_name, ), function_name``. Sol does not provide one because many codebases already have `one similar to this`_.
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Here's an example below of various ways to use ``sol::c_call``:
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.. code-block:: cpp
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:linenos:
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:caption: Compile-time transported function calls
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#include "sol.hpp"
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int f1(int) { return 32; }
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int f2(int, int) { return 1; }
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struct fer {
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double f3(int, int) {
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return 2.5;
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}
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};
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int main() {
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sol::state lua;
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// overloaded function f
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lua.set("f", sol::c_call<sol::wrap<decltype(&f1), &f1>, sol::wrap<decltype(&f2), &f2>, sol::wrap<decltype(&fer::f3), &fer::f3>>);
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// singly-wrapped function
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lua.set("g", sol::c_call<sol::wrap<decltype(&f1), &f1>>);
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// without the 'sol::wrap' boilerplate
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lua.set("h", sol::c_call<decltype(&f2), &f2>);
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// object used for the 'fer' member function call
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lua.set("obj", fer());
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// call them like any other bound function
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lua.script("r1 = f(1)");
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lua.script("r2 = f(1, 2)");
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lua.script("r3 = f(obj, 1, 2)");
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lua.script("r4 = g(1)");
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lua.script("r5 = h(1, 2)");
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// get the results and see
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// if it worked out
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int r1 = lua["r1"];
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// r1 == 32
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int r2 = lua["r2"];
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// r2 == 1
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double r3 = lua["r3"];
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// r3 == 2.5
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int r4 = lua["r4"];
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// r4 == 32
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int r5 = lua["r5"];
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// r5 == 1
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return 0;
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}
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.. _one similar to this: http://stackoverflow.com/a/5628222/5280922
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