autocast.hpp

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/** ************************************************************************************************
 * \file
 * This header file is part of module \alib_expressions of the \aliblong.
 *
 * \emoji :copyright: 2013-2024 A-Worx GmbH, Germany.
 * Published under \ref mainpage_license "Boost Software License".
 **************************************************************************************************/
#ifndef HPP_ALIB_EXPRESSIONS_PLUGINS_AUTOCAST
#define HPP_ALIB_EXPRESSIONS_PLUGINS_AUTOCAST
 
#ifndef HPP_ALIB_EXPRESSIONS_COMPILERPLUGIN
#   include "alib/expressions/compilerplugin.hpp"
#endif
 
 
namespace alib {  namespace expressions { namespace plugins {
 
/** ************************************************************************************************
 * This built-in compiler plug-in of \alib_expressions_nl, performs auto-casts only if two
 * different types are given. In this case, the following casts are performed:
 *
 * 1. If one argument is of type \alib{expressions;Types::String}, the other is converted to
 *    string. The expression function returned for (optional) decompilation is \b "String()".
 *
 * 2. If one argument is of type \alib{expressions;Types::Float} and the other of type
 *    \alib{expressions;Types::Integer}, the integral value is casted to floating point.
 *    The expression function returned for (optional) decompilation is \b "Float()".
 *
 * 3. If one argument is of type \alib{expressions;Types::Float} and the other of type
 *    \alib{expressions;Types::Boolean}, the boolean value is casted to floating point.
 *    The expression function returned for (optional) decompilation is \b "Float()".
 *
 * 4. If one argument is of type \alib{expressions;Types::Integer} and the other of type
 *    \alib{expressions;Types::Boolean}, the boolean value is casted to integer.
 *    The expression function returned for (optional) decompilation is \b "Integer()".
 *
 * 5. If one argument is of type \alib{expressions;Types::Boolean}, the other is converted to
 *    boolean using an internal callback function that simply invokes box-function
 *    \alib{boxing;FIsTrue}.
 *    The expression function returned for (optional) decompilation is \b "Boolean()".
 **************************************************************************************************/
struct AutoCast  : public CompilerPlugin
{
    /** ********************************************************************************************
     * Constructor.
     * @param compiler The compiler we will get attached to.
     **********************************************************************************************/
    ALIB_API        AutoCast( Compiler& compiler );
 
    /** ********************************************************************************************
     * Virtual destructor.
     **********************************************************************************************/
    virtual        ~AutoCast()                                                              override
    {}
 
    /** ********************************************************************************************
     * Offers auto-cast functions for built-in types.
     *
     * @param[out] ciAutoCast  The compilation result.
     * @return \c true if an entry was found. \c false otherwise.
     **********************************************************************************************/
    ALIB_API
    virtual bool    TryCompilation( CIAutoCast& ciAutoCast )                               override;
};
 
}}} // namespace [alib::expressions::detail]
 
#endif // HPP_ALIB_EXPRESSIONS_PLUGINS_AUTOCAST