From ccdf5ce031df3ad10c36d520e75fe126d0b19166 Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Tue, 5 Oct 2021 06:45:41 +0300
Subject: [PATCH] Track the type suffix independently for better decomposition
 of functions and arrays

---
 include/boost/core/type_name.hpp | 267 ++++++++++++++-----------------
 test/type_name_test.cpp          |  18 +++
 2 files changed, 136 insertions(+), 149 deletions(-)

diff --git a/include/boost/core/type_name.hpp b/include/boost/core/type_name.hpp
index 8632f81..d31750b 100644
--- a/include/boost/core/type_name.hpp
+++ b/include/boost/core/type_name.hpp
@@ -244,7 +244,7 @@ inline std::string tn_to_string( std::size_t n )
 template<class T> int tn_add_each_impl( std::string& st )
 {
     if( !st.empty() ) st += ", ";
-    st += type_name( tn_identity<T>() );
+    st += type_name( tn_identity<T>(), "" );
     return 0;
 };
 
@@ -262,51 +262,51 @@ template<class... T> std::string tn_add_each()
 
 // primary
 
-template<class T> std::string type_name( tn_identity<T> )
+template<class T> std::string type_name( tn_identity<T>, std::string const& suffix )
 {
-    return typeid_name<T>();
+    return typeid_name<T>() + suffix;
 }
 
 // cv
 
 #if !defined(BOOST_MSVC) || BOOST_MSVC >= 1900
 
-template<class T> std::string type_name( tn_identity<T const> )
+template<class T> std::string type_name( tn_identity<T const>, std::string const& suffix )
 {
-    return type_name( tn_identity<T>() ) + " const";
+    return type_name( tn_identity<T>(), " const" + suffix );
 }
 
-template<class T> std::string type_name( tn_identity<T volatile> )
+template<class T> std::string type_name( tn_identity<T volatile>, std::string const& suffix )
 {
-    return type_name( tn_identity<T>() ) + " volatile";
+    return type_name( tn_identity<T>(), " volatile" + suffix );
 }
 
-template<class T> std::string type_name( tn_identity<T const volatile> )
+template<class T> std::string type_name( tn_identity<T const volatile>, std::string const& suffix )
 {
-    return type_name( tn_identity<T>() ) + " const volatile";
+    return type_name( tn_identity<T>(), " const volatile" + suffix );
 }
 
 #else
 
 template<class T>
 typename tn_enable_if<!tn_is_function<T>::value, std::string>::type
-type_name( tn_identity<T const> )
+type_name( tn_identity<T const>, std::string const& suffix )
 {
-    return type_name( tn_identity<T>() ) + " const";
+    return type_name( tn_identity<T>(), " const" + suffix );
 }
 
 template<class T>
 typename tn_enable_if<!tn_is_function<T>::value, std::string>::type
-type_name( tn_identity<T volatile> )
+type_name( tn_identity<T volatile>, std::string const& suffix )
 {
-    return type_name( tn_identity<T>() ) + " volatile";
+    return type_name( tn_identity<T>(), " volatile" + suffix );
 }
 
 template<class T>
 typename tn_enable_if<!tn_is_function<T>::value, std::string>::type
-type_name( tn_identity<T const volatile> )
+type_name( tn_identity<T const volatile>, std::string const& suffix )
 {
-    return type_name( tn_identity<T>() ) + " const volatile";
+    return type_name( tn_identity<T>(), " const volatile" + suffix );
 }
 
 #endif
@@ -315,27 +315,27 @@ type_name( tn_identity<T const volatile> )
 
 #if !defined(BOOST_MSVC) || BOOST_MSVC >= 1900
 
-template<class T> std::string type_name( tn_identity<T&> )
+template<class T> std::string type_name( tn_identity<T&>, std::string const& suffix )
 {
-    return type_name( tn_identity<T>() ) + "&";
+    return type_name( tn_identity<T>(), "&" + suffix );
 }
 
 #else
 
 template<class T>
 typename tn_enable_if<!tn_is_reference<T>::value, std::string>::type
-type_name( tn_identity<T&> )
+type_name( tn_identity<T&>, std::string const& suffix )
 {
-    return type_name( tn_identity<T>() ) + "&";
+    return type_name( tn_identity<T>(), "&" + suffix );
 }
 
 #endif
 
 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
 
-template<class T> std::string type_name( tn_identity<T&&> )
+template<class T> std::string type_name( tn_identity<T&&>, std::string const& suffix )
 {
-    return type_name( tn_identity<T>() ) + "&&";
+    return type_name( tn_identity<T>(), "&&" + suffix );
 }
 
 #endif
@@ -344,81 +344,34 @@ template<class T> std::string type_name( tn_identity<T&&> )
 
 #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
 
-template<class R, class... A> std::string type_name( tn_identity<R(A...)> )
+template<class R, class... A> std::string type_name( tn_identity<R(A...)>, std::string const& suffix )
 {
-    return type_name( tn_identity<R>() ) + '(' + tn_add_each<A...>() + ')';
+    std::string r = type_name( tn_identity<R>(), "" );
+
+    if( !suffix.empty() )
+    {
+        r += '(' + suffix + ')';
+    }
+
+    r += '(' + tn_add_each<A...>() + ')';
+
+    return r;
 }
 
 #endif
 
 // pointers
 
-template<class T> std::string type_name( tn_identity<T*> )
+template<class T> std::string type_name( tn_identity<T*>, std::string const& suffix )
 {
-    return type_name( tn_identity<T>() ) + "*";
+    return type_name( tn_identity<T>(), "*" + suffix );
 }
 
-#if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
-
-// function references
-
-template<class R, class... A> std::string type_name( tn_identity<R(&)(A...)> )
-{
-    return type_name( tn_identity<R>() ) + "(&)(" + tn_add_each<A...>() + ')';
-}
-
-#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
-
-template<class R, class... A> std::string type_name( tn_identity<R(&&)(A...)> )
-{
-    return type_name( tn_identity<R>() ) + "(&&)(" + tn_add_each<A...>() + ')';
-}
-
-#endif
-
-// function pointers
-
-template<class R, class... A> std::string type_name( tn_identity<R(*)(A...)> )
-{
-    return type_name( tn_identity<R>() ) + "(*)(" + tn_add_each<A...>() + ')';
-}
-
-template<class R, class... A> std::string type_name( tn_identity<R(*&)(A...)> )
-{
-    return type_name( tn_identity<R>() ) + "(*&)(" + tn_add_each<A...>() + ')';
-}
-
-template<class R, class... A> std::string type_name( tn_identity<R(* const)(A...)> )
-{
-    return type_name( tn_identity<R>() ) + "(* const)(" + tn_add_each<A...>() + ')';
-}
-
-template<class R, class... A> std::string type_name( tn_identity<R(* const&)(A...)> )
-{
-    return type_name( tn_identity<R>() ) + "(* const&)(" + tn_add_each<A...>() + ')';
-}
-
-#if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
-
-template<class R, class... A> std::string type_name( tn_identity<R(*&&)(A...)> )
-{
-    return type_name( tn_identity<R>() ) + "(*&&)(" + tn_add_each<A...>() + ')';
-}
-
-template<class R, class... A> std::string type_name( tn_identity<R(* const&&)(A...)> )
-{
-    return type_name( tn_identity<R>() ) + "(* const&&)(" + tn_add_each<A...>() + ')';
-}
-
-#endif
-
-#endif
-
 // arrays
 
 template<class T> std::pair<std::string, std::string> array_prefix_suffix( tn_identity<T> )
 {
-    return std::pair<std::string, std::string>( type_name( tn_identity<T>() ), "" );
+    return std::pair<std::string, std::string>( type_name( tn_identity<T>(), "" ), "" );
 }
 
 template<class T, std::size_t N> std::pair<std::string, std::string> array_prefix_suffix( tn_identity<T[N]> )
@@ -430,163 +383,179 @@ template<class T, std::size_t N> std::pair<std::string, std::string> array_prefi
     return r;
 }
 
-template<class T> std::string array_type_name( tn_identity<T[]> )
+template<class T> std::string array_type_name( tn_identity<T[]>, std::string const& suffix )
 {
     std::pair<std::string, std::string> r = array_prefix_suffix( tn_identity<T>() );
-    return r.first + "[]" + r.second;
+
+    if( suffix.empty() )
+    {
+        return r.first + "[]" + r.second;
+    }
+    else
+    {
+        return r.first + '(' + suffix + ")[]" + r.second;
+    }
 }
 
-template<class T> std::string type_name( tn_identity<T[]> )
+template<class T> std::string type_name( tn_identity<T[]>, std::string const& suffix )
 {
-    return array_type_name( tn_identity<T[]>() );
+    return array_type_name( tn_identity<T[]>(), suffix );
 }
 
-template<class T> std::string type_name( tn_identity<T const[]> )
+template<class T> std::string type_name( tn_identity<T const[]>, std::string const& suffix )
 {
-    return array_type_name( tn_identity<T const[]>() );
+    return array_type_name( tn_identity<T const[]>(), suffix );
 }
 
-template<class T> std::string type_name( tn_identity<T volatile[]> )
+template<class T> std::string type_name( tn_identity<T volatile[]>, std::string const& suffix )
 {
-    return array_type_name( tn_identity<T volatile[]>() );
+    return array_type_name( tn_identity<T volatile[]>(), suffix );
 }
 
-template<class T> std::string type_name( tn_identity<T const volatile[]> )
+template<class T> std::string type_name( tn_identity<T const volatile[]>, std::string const& suffix )
 {
-    return array_type_name( tn_identity<T const volatile[]>() );
+    return array_type_name( tn_identity<T const volatile[]>(), suffix );
 }
 
-template<class T, std::size_t N> std::string array_type_name( tn_identity<T[N]> )
+template<class T, std::size_t N> std::string array_type_name( tn_identity<T[N]>, std::string const& suffix )
 {
     std::pair<std::string, std::string> r = array_prefix_suffix( tn_identity<T[N]>() );
-    return r.first + r.second;
+
+    if( suffix.empty() )
+    {
+        return r.first + r.second;
+    }
+    else
+    {
+        return r.first + '(' + suffix + ")" + r.second;
+    }
 }
 
-template<class T, std::size_t N> std::string type_name( tn_identity<T[N]> )
+template<class T, std::size_t N> std::string type_name( tn_identity<T[N]>, std::string const& suffix )
 {
-    return array_type_name( tn_identity<T[N]>() );
+    return array_type_name( tn_identity<T[N]>(), suffix );
 }
 
-template<class T, std::size_t N> std::string type_name( tn_identity<T const[N]> )
+template<class T, std::size_t N> std::string type_name( tn_identity<T const[N]>, std::string const& suffix )
 {
-    return array_type_name( tn_identity<T const[N]>() );
+    return array_type_name( tn_identity<T const[N]>(), suffix );
 }
 
-template<class T, std::size_t N> std::string type_name( tn_identity<T volatile[N]> )
+template<class T, std::size_t N> std::string type_name( tn_identity<T volatile[N]>, std::string const& suffix )
 {
-    return array_type_name( tn_identity<T volatile[N]>() );
+    return array_type_name( tn_identity<T volatile[N]>(), suffix );
 }
 
-template<class T, std::size_t N> std::string type_name( tn_identity<T const volatile[N]> )
+template<class T, std::size_t N> std::string type_name( tn_identity<T const volatile[N]>, std::string const& suffix )
 {
-    return array_type_name( tn_identity<T const volatile[N]>() );
+    return array_type_name( tn_identity<T const volatile[N]>(), suffix );
 }
 
 // nullptr_t
 
 #if !defined(BOOST_NO_CXX11_NULLPTR)
 
-inline std::string type_name( tn_identity<std::nullptr_t> )
+inline std::string type_name( tn_identity<std::nullptr_t>, std::string const& suffix )
 {
-    return "std::nullptr_t";
+    return "std::nullptr_t" + suffix;
 }
 
 #endif
 
 // strings
 
-template<template<class Ch, class Tr, class A> class L, class Ch> std::string type_name( tn_identity< L<Ch, std::char_traits<Ch>, std::allocator<Ch> > > )
+template<template<class Ch, class Tr, class A> class L, class Ch> std::string type_name( tn_identity< L<Ch, std::char_traits<Ch>, std::allocator<Ch> > >, std::string const& suffix )
 {
     std::string tn = sequence_template_name< L<Ch, std::char_traits<Ch>, std::allocator<Ch> > >();
-    return tn + '<' + type_name( tn_identity<Ch>() ) + '>';
+    return tn + '<' + type_name( tn_identity<Ch>(), "" ) + '>' + suffix;
 }
 
-inline std::string type_name( tn_identity<std::string> )
+inline std::string type_name( tn_identity<std::string>, std::string const& suffix )
 {
-    return "std::string";
+    return "std::string" + suffix;
 }
 
-inline std::string type_name( tn_identity<std::wstring> )
+inline std::string type_name( tn_identity<std::wstring>, std::string const& suffix )
 {
-    return "std::wstring";
+    return "std::wstring" + suffix;
 }
 
 #if !defined(BOOST_NO_CXX11_CHAR16_T)
 
-inline std::string type_name( tn_identity<std::u16string> )
+inline std::string type_name( tn_identity<std::u16string>, std::string const& suffix )
 {
-    return "std::u16string";
+    return "std::u16string" + suffix;
 }
 
 #endif
 
 #if !defined(BOOST_NO_CXX11_CHAR32_T)
 
-inline std::string type_name( tn_identity<std::u32string> )
+inline std::string type_name( tn_identity<std::u32string>, std::string const& suffix )
 {
-    return "std::u32string";
+    return "std::u32string" + suffix;
 }
 
 #endif
 
 #if defined(__cpp_char8_t) && __cpp_char8_t >= 201811L
 
-inline std::string type_name( tn_identity<std::basic_string<char8_t>> )
+inline std::string type_name( tn_identity<std::basic_string<char8_t>>, std::string const& suffix )
 {
-    return "std::u8string";
+    return "std::u8string" + suffix;
 }
 
 #endif
 
 // string views (et al)
 
-template<template<class Ch, class Tr> class L, class Ch> std::string type_name( tn_identity< L<Ch, std::char_traits<Ch> > > )
+template<template<class Ch, class Tr> class L, class Ch> std::string type_name( tn_identity< L<Ch, std::char_traits<Ch> > >, std::string const& suffix )
 {
     std::string tn = sequence_template_name< L<Ch, std::char_traits<Ch> > >();
-    return tn + '<' + type_name( tn_identity<Ch>() ) + '>';
+    return tn + '<' + type_name( tn_identity<Ch>(), "" ) + '>' + suffix;
 }
 
 // needed for libstdc++
-inline std::string type_name( tn_identity<std::ostream> )
+inline std::string type_name( tn_identity<std::ostream>, std::string const& suffix )
 {
-    return "std::ostream";
+    return "std::ostream" + suffix;
 }
 
 #if !defined(BOOST_NO_CXX17_HDR_STRING_VIEW)
 
-inline std::string type_name( tn_identity<std::string_view> )
+inline std::string type_name( tn_identity<std::string_view>, std::string const& suffix )
 {
-    return "std::string_view";
+    return "std::string_view" + suffix;
 }
 
-inline std::string type_name( tn_identity<std::wstring_view> )
+inline std::string type_name( tn_identity<std::wstring_view>, std::string const& suffix )
 {
-    return "std::wstring_view";
+    return "std::wstring_view" + suffix;
 }
 
 #if !defined(BOOST_NO_CXX11_CHAR16_T)
 
-inline std::string type_name( tn_identity<std::u16string_view> )
+inline std::string type_name( tn_identity<std::u16string_view>, std::string const& suffix )
 {
-    return "std::u16string_view";
+    return "std::u16string_view" + suffix;
 }
 
 #endif
 
 #if !defined(BOOST_NO_CXX11_CHAR32_T)
 
-inline std::string type_name( tn_identity<std::u32string_view> )
+inline std::string type_name( tn_identity<std::u32string_view>, std::string const& suffix )
 {
-    return "std::u32string_view";
+    return "std::u32string_view" + suffix;
 }
 
 #endif
 
 #if defined(__cpp_char8_t) && __cpp_char8_t >= 201811L
 
-inline std::string type_name( tn_identity<std::basic_string_view<char8_t>> )
+inline std::string type_name( tn_identity<std::basic_string_view<char8_t>>, std::string const& suffix )
 {
-    return "std::u8string_view";
+    return "std::u8string_view" + suffix;
 }
 
 #endif
@@ -597,87 +566,87 @@ inline std::string type_name( tn_identity<std::basic_string_view<char8_t>> )
 
 #if !defined(BOOST_NO_CXX11_VARIADIC_TEMPLATES)
 
-template<template<class...> class L, class... T> std::string type_name( tn_identity< L<T...> > )
+template<template<class...> class L, class... T> std::string type_name( tn_identity< L<T...> >, std::string const& suffix )
 {
     std::string tn = class_template_name< L<T...> >();
     std::string st = tn_add_each<T...>();
 
-    return tn + '<' + st + '>';
+    return tn + '<' + st + '>' + suffix;
 }
 
 #else
 
-template<template<class T1> class L, class T1> std::string type_name( tn_identity< L<T1> > )
+template<template<class T1> class L, class T1> std::string type_name( tn_identity< L<T1> >, std::string const& suffix )
 {
     std::string tn = class_template_name< L<T1> >();
-    return tn + '<' + type_name( tn_identity<T1>() ) + '>';
+    return tn + '<' + type_name( tn_identity<T1>(), "" ) + '>' + suffix;
 }
 
-template<template<class T1, class T2> class L, class T1, class T2> std::string type_name( tn_identity< L<T1, T2> > )
+template<template<class T1, class T2> class L, class T1, class T2> std::string type_name( tn_identity< L<T1, T2> >, std::string const& suffix )
 {
     std::string tn = class_template_name< L<T1, T2> >();
-    return tn + '<' + type_name( tn_identity<T1>() ) + ", " + type_name( tn_identity<T2>() ) + '>';
+    return tn + '<' + type_name( tn_identity<T1>(), "" ) + ", " + type_name( tn_identity<T2>(), "" ) + '>' + suffix;
 }
 
 #endif
 
 // sequence containers
 
-template<template<class T, class A> class L, class T> std::string type_name( tn_identity< L<T, std::allocator<T> > > )
+template<template<class T, class A> class L, class T> std::string type_name( tn_identity< L<T, std::allocator<T> > >, std::string const& suffix )
 {
     std::string tn = sequence_template_name< L<T, std::allocator<T> > >();
-    return tn + '<' + type_name( tn_identity<T>() ) + '>';
+    return tn + '<' + type_name( tn_identity<T>(), "" ) + '>' + suffix;
 }
 
 // set
 
-template<template<class T, class Pr, class A> class L, class T> std::string type_name( tn_identity< L<T, std::less<T>, std::allocator<T> > > )
+template<template<class T, class Pr, class A> class L, class T> std::string type_name( tn_identity< L<T, std::less<T>, std::allocator<T> > >, std::string const& suffix )
 {
     std::string tn = set_template_name< L<T, std::less<T>, std::allocator<T> > >();
-    return tn + '<' + type_name( tn_identity<T>() ) + '>';
+    return tn + '<' + type_name( tn_identity<T>(), "" ) + '>' + suffix;
 }
 
 // map
 
-template<template<class T, class U, class Pr, class A> class L, class T, class U> std::string type_name( tn_identity< L<T, U, std::less<T>, std::allocator<std::pair<T const, U> > > > )
+template<template<class T, class U, class Pr, class A> class L, class T, class U> std::string type_name( tn_identity< L<T, U, std::less<T>, std::allocator<std::pair<T const, U> > > >, std::string const& suffix )
 {
     std::string tn = map_template_name< L<T, U, std::less<T>, std::allocator<std::pair<T const, U> > > >();
-    return tn + '<' + type_name( tn_identity<T>() ) + ", " + type_name( tn_identity<U>() ) +  '>';
+    return tn + '<' + type_name( tn_identity<T>(), "" ) + ", " + type_name( tn_identity<U>(), "" ) +  '>' + suffix;
 }
 
 #if !defined(BOOST_NO_CXX11_HDR_FUNCTIONAL)
 
 // unordered_set
 
-template<template<class T, class H, class Eq, class A> class L, class T> std::string type_name( tn_identity< L<T, std::hash<T>, std::equal_to<T>, std::allocator<T> > > )
+template<template<class T, class H, class Eq, class A> class L, class T> std::string type_name( tn_identity< L<T, std::hash<T>, std::equal_to<T>, std::allocator<T> > >, std::string const& suffix )
 {
     std::string tn = set_template_name< L<T, std::hash<T>, std::equal_to<T>, std::allocator<T> > >();
-    return tn + '<' + type_name( tn_identity<T>() ) + '>';
+    return tn + '<' + type_name( tn_identity<T>(), "" ) + '>' + suffix;
 }
 
 // unordered_map
 
-template<template<class T, class U, class H, class Eq, class A> class L, class T, class U> std::string type_name( tn_identity< L<T, U, std::hash<T>, std::equal_to<T>, std::allocator<std::pair<T const, U> > > > )
+template<template<class T, class U, class H, class Eq, class A> class L, class T, class U> std::string type_name( tn_identity< L<T, U, std::hash<T>, std::equal_to<T>, std::allocator<std::pair<T const, U> > > >, std::string const& suffix )
 {
     std::string tn = map_template_name< L<T, U, std::hash<T>, std::equal_to<T>, std::allocator<std::pair<T const, U> > > >();
-    return tn + '<' + type_name( tn_identity<T>() ) + ", " + type_name( tn_identity<U>() ) +  '>';
+    return tn + '<' + type_name( tn_identity<T>(), "" ) + ", " + type_name( tn_identity<U>(), "" ) +  '>' + suffix;
 }
 
 #endif
 
 // array
 
-template<template<class T, std::size_t N> class L, class T, std::size_t N> std::string type_name( tn_identity< L<T, N> > )
+template<template<class T, std::size_t N> class L, class T, std::size_t N> std::string type_name( tn_identity< L<T, N> >, std::string const& suffix )
 {
     std::string tn = array_template_name< L<T, N> >();
-    return tn + '<' + type_name( tn_identity<T>() ) + ", " + tn_to_string( N ) + '>';
+    return tn + '<' + type_name( tn_identity<T>(), "" ) + ", " + tn_to_string( N ) + '>' + suffix;
 }
 
 } // namespace detail
 
 template<class T> std::string type_name()
 {
-    return core::detail::type_name( core::detail::tn_identity<T>() );
+    return core::detail::type_name( core::detail::tn_identity<T>(), "" );
 }
 
 } // namespace core
diff --git a/test/type_name_test.cpp b/test/type_name_test.cpp
index b3439c1..ebd3895 100644
--- a/test/type_name_test.cpp
+++ b/test/type_name_test.cpp
@@ -111,6 +111,12 @@ int main()
     TEST(int(float, A, B*));
 
     TEST(void(*)());
+    TEST(void(**)());
+    TEST(void(***)());
+
+    TEST(void(* const* const*)());
+    TEST(void(* const* const&)());
+
     TEST(void(&)());
 
 #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES)
@@ -125,17 +131,29 @@ int main()
     TEST(A volatile[]);
     TEST(A const volatile[]);
 
+    TEST(A(&)[]);
+    TEST(A const(***)[]);
+
     TEST(B[1]);
     TEST(B const[1]);
     TEST(B volatile[1]);
     TEST(B const volatile[1]);
 
+    TEST(B(&)[1]);
+    TEST(B const(***)[1]);
+
     TEST(A[][2][3]);
     TEST(A const[][2][3]);
 
+    TEST(A(&)[][2][3]);
+    TEST(A const(***)[][2][3]);
+
     TEST(B[1][2][3]);
     TEST(B const volatile[1][2][3]);
 
+    TEST(B(&)[1][2][3]);
+    TEST(B const volatile(***)[1][2][3]);
+
 #if !defined(BOOST_NO_CXX11_NULLPTR)
 
     TEST(std::nullptr_t);