str_format.hpp

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#ifndef EAGINE_STR_FORMAT_HPP
#define EAGINE_STR_FORMAT_HPP
 
#include "config/basic.hpp"
#include "integer_range.hpp"
#include "span.hpp"
#include <array>
#include <string>
 
namespace eagine {
//------------------------------------------------------------------------------
class format_string_and_list_base {
 
protected:
    format_string_and_list_base(std::string&& fmt_str) noexcept
      : _fmt_str(std::move(fmt_str)) {}
 
    format_string_and_list_base(format_string_and_list_base& that) noexcept
      : _fmt_str(std::move(that._fmt_str)) {}
 
    format_string_and_list_base(format_string_and_list_base&&) noexcept =
      default;
    format_string_and_list_base(const format_string_and_list_base&) = default;
 
    auto operator=(format_string_and_list_base&&) noexcept
      -> format_string_and_list_base& = default;
 
    auto operator=(const format_string_and_list_base&)
      -> format_string_and_list_base& = default;
 
    ~format_string_and_list_base() noexcept = default;
 
    auto _fmt(span<const std::string> values) const -> std::string;
 
private:
    std::string _fmt_str;
};
//------------------------------------------------------------------------------
template <span_size_t N>
class format_string_and_list;
 
template <>
class format_string_and_list<0> : public format_string_and_list_base {
public:
    format_string_and_list(std::string& fmt_str) noexcept
      : format_string_and_list_base(std::move(fmt_str)) {}
 
    operator std::string() const {
        return _fmt({});
    }
};
//------------------------------------------------------------------------------
template <span_size_t N>
class format_string_and_list : public format_string_and_list_base {
 
public:
    format_string_and_list(
      format_string_and_list<N - 1>&& prev,
      std::string&& val) noexcept
      : format_string_and_list_base(prev) {
        for(auto i : integer_range(N - 1)) {
            _list[i] = std::move(prev._list[i]);
        }
        _list[N - 1] = std::move(val);
    }
 
    operator std::string() const {
        return _fmt(view(_list));
    }
 
public:
    std::array<std::string, N> _list{};
};
//------------------------------------------------------------------------------
template <>
class format_string_and_list<1> : public format_string_and_list_base {
 
public:
    format_string_and_list(
      format_string_and_list<0>&& prev,
      std::string&& val) noexcept
      : format_string_and_list_base(prev) {
        _list[0] = std::move(val);
    }
 
    operator std::string() const {
        return _fmt(view(_list));
    }
 
public:
    std::array<std::string, 1> _list{};
};
//------------------------------------------------------------------------------
template <span_size_t N>
static inline auto
operator%(format_string_and_list<N>&& fsal, std::string&& val) noexcept
  -> format_string_and_list<N + 1> {
    return {std::move(fsal), std::move(val)};
}
//------------------------------------------------------------------------------
static inline auto format(std::string&& fmt_str) noexcept
  -> format_string_and_list<0> {
    return {fmt_str};
}
//------------------------------------------------------------------------------
} // namespace eagine
 
#if !EAGINE_LINK_LIBRARY || defined(EAGINE_IMPLEMENTING_LIBRARY)
#include <eagine/str_format.inl>
#endif
 
#endif // EAGINE_STR_FORMAT_HPP