bslstl_isconvertibletostringview.h

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/// @file bslstl_isconvertibletostringview.h
///
/// The content of this file has been pre-processed for Doxygen.
///
 
 
// bslstl_isconvertibletostringview.h                                -*-C++-*-
#ifndef INCLUDED_BSLSTL_ISCONVERTIBLETOSTRINGVIEW
#define INCLUDED_BSLSTL_ISCONVERTIBLETOSTRINGVIEW
 
#include <bsls_ident.h>
BSLS_IDENT("$Id: $")
 
/// @defgroup bslstl_isconvertibletostringview bslstl_isconvertibletostringview
/// @brief  Provide a compile-time check for types convertible to string_view.
/// @addtogroup bsl
/// @{
/// @addtogroup bslstl
/// @{
/// @addtogroup bslstl_isconvertibletostringview
/// @{
///
/// <h1> Outline </h1>
/// * <a href="#bslstl_isconvertibletostringview-purpose"> Purpose</a>
/// * <a href="#bslstl_isconvertibletostringview-classes"> Classes </a>
/// * <a href="#bslstl_isconvertibletostringview-description"> Description </a>
///   * <a href="#bslstl_isconvertibletostringview-usage"> Usage </a>
///     * <a href="#bslstl_isconvertibletostringview-example-1-determine-if-a-type-is-convertible-to-a-string-view"> Example 1: Determine If a Type Is Convertible to a String View </a>
///
/// # Purpose {#bslstl_isconvertibletostringview-purpose}
/// Provide a compile-time check for types convertible to string_view.
///
/// # Classes {#bslstl_isconvertibletostringview-classes}
///
/// -  bslstl::IsConvertibleToStringView: meta-function for string_view conversion
///
/// @see  bslmf_isconvertible, bslstl_isconvertibletocstring,
///           bslstl_stringview
///
/// # Description {#bslstl_isconvertibletostringview-description}
/// This component provides a meta-function,
/// `bslstl::IsConvertibleToStringView`, that may be used to query (at
/// compile-time) whether a type is convertible to a
/// `bsl::basic_string_view<CHAR_TYPE, CHAR_TRAITS>`.
///
/// `bslstl::IsConvertibleToStringView` meets the requirements of the
/// `UnaryTypeTrait` concept defined in the C++ standard [meta.rqmts] with a
/// base characteristic of `bsl::true_type` if the (template parameter) `TYPE`
/// is convertible to `bsl::basic_string_view<CHAR_TYPE, CHAR_TRAITS>`, and a
/// base characteristic of `bsl::false_type` otherwise.
///
/// This trait is particularly useful for implementing functions that accept
/// "string-view-like" types, as specified in C++17 and later standards.
///
/// ## Usage {#bslstl_isconvertibletostringview-usage}
///
///
/// In this section we show the intended use of this component.
///
/// ### Example 1: Determine If a Type Is Convertible to a String View {#bslstl_isconvertibletostringview-example-1-determine-if-a-type-is-convertible-to-a-string-view}
///
///
/// Suppose that we want to determine whether various types are convertible to
/// `bsl::string_view`.
///
/// First, we note that `bsl::string_view` itself is convertible:
/// @code
/// assert((bslstl::IsConvertibleToStringView<char,
///                                           std::char_traits<char>,
///                                           bsl::string_view>::value));
/// @endcode
/// Next, we verify that `const char *` is convertible to string_view:
/// @code
/// assert((bslstl::IsConvertibleToStringView<char,
///                                           std::char_traits<char>,
///                                           const char *>::value));
/// @endcode
/// Finally, we verify that an unrelated type is not convertible:
/// @code
/// assert((!bslstl::IsConvertibleToStringView<char,
///                                            std::char_traits<char>,
///                                            int>::value));
/// @endcode
/// @}
/** @} */
/** @} */
 
/** @addtogroup bsl
 * @{
 */
/** @addtogroup bslstl
 * @{
 */
/** @addtogroup bslstl_isconvertibletostringview
 * @{
 */
 
#include <bslscm_version.h>
 
#include <bslstl_stringview.h>
 
#include <bslmf_integralconstant.h>
#include <bslmf_isconvertible.h>
 
 
namespace bslstl {
 
                    // ==================================
                    // struct IsConvertibleToStringView
                    // ==================================
 
/// This `struct` template implements a meta-function to determine if the
/// (template parameter) `t_TYPE` is convertible to
/// `bsl::basic_string_view<t_CHAR_TYPE, t_CHAR_TRAITS>`.
template <class t_CHAR_TYPE, class t_CHAR_TRAITS, class t_TYPE>
struct IsConvertibleToStringView
: bsl::is_convertible<t_TYPE,
                      bsl::basic_string_view<t_CHAR_TYPE, t_CHAR_TRAITS> > {
};
 
/// This partial specialization of `IsConvertibleToStringView` is
/// instantiated when `const t_CHAR_TYPE (&)[]` (an unbounded array
/// reference) is tested for convertibility to string view.  This handles
/// edge cases with certain compilers where `bsl::is_convertible` may not
/// correctly handle incomplete array types.
template <class t_CHAR_TYPE, class t_CHAR_TRAITS>
struct IsConvertibleToStringView<t_CHAR_TYPE,
                                 t_CHAR_TRAITS,
                                 const t_CHAR_TYPE (&)[]>
: bsl::true_type {
};
 
}  // close package namespace
 
 
#endif
 
// ----------------------------------------------------------------------------
// Copyright 2026 Bloomberg Finance L.P.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ----------------------------- END-OF-FILE ----------------------------------
 
/** @} */
/** @} */
/** @} */