input_concept.h

// Description: Input concept
// Documentation: input.txt

#ifndef PASTELSYS_INPUT_CONCEPT_H
#define PASTELSYS_INPUT_CONCEPT_H

#include "pastel/sys/mytypes.h"

#include <type_traits>

namespace Pastel
{

    struct Input_Concept
    {
        template <typename Type>
        auto requires_(Type&& t) -> decltype
        (
            conceptCheck(
                //! Returns an approximation of the number of elements left.
                /*!
               This number is only a hint;
               the implementation must be able to deal with
               either a smaller or a larger amounts of elements.
               This can be used, for example, to pre-allocate memory
               for an array. A zero specifies that the number is 
               not known; it conveys zero information.

               Must return a non-negative number.
               */
                Concept::convertsTo<integer>(addConst(t).nHint()),

                //! Returns whether there are elements left.
                Concept::convertsTo<bool>(addConst(t).empty()),

                //! Returns the current element.
                /*!
               Preconditions:
               !empty()
               */
                (addConst(t).get(), 0),

                //! Drops the current element off from the input.
                /*!
               Preconditions:
               !empty()
               */
                (t.pop(), 0)
            )
        );
    };

}

#include "pastel/sys/input/input_return.h"
#include "pastel/sys/input/input_value.h"

#endif