Convert some uses of lambda to more concise std::mem_fn

src/alias_registry.cc

@@ -57,7 +57,7 @@ Vector<std::pair<StringView, StringView>> AliasRegistry::flatten_aliases() const
         res = m_parent->flatten_aliases();
     for (auto& alias : m_aliases)
     {
-        if (not contains(res | transform([](const AliasDesc& val) { return val.first; }), alias.key))
+        if (not contains(res | transform(std::mem_fn(&AliasDesc::first)), alias.key))
             res.emplace_back(alias.key, alias.value);
     }
     return res;

src/buffer_manager.cc

@@ -54,7 +54,6 @@ void BufferManager::delete_buffer(Buffer& buffer)
                       { return p.get() == &buffer; });
     kak_assert(it != m_buffers.end());
 
-
     ClientManager::instance().ensure_no_client_uses_buffer(buffer);
 
     m_buffer_trash.emplace_back(std::move(*it));

src/command_manager.cc

@@ -531,16 +531,15 @@ Completions CommandManager::complete_command_name(const Context& context,
 {
     auto commands = m_commands
             | filter([](const CommandMap::value_type& cmd) { return not (cmd.second.flags & CommandFlags::Hidden); })
-            | transform([](const CommandMap::value_type& cmd) { return StringView{cmd.first}; });
+            | transform(std::mem_fn(&CommandMap::value_type::first));
 
     if (not with_aliases)
         return {0, query.length(), Kakoune::complete(query, query.length(), commands)};
 
     auto candidates = Kakoune::complete(query, query.length(),
         concatenated(commands,
-                     context.aliases().flatten_aliases()
-                    | transform([](AliasRegistry::AliasDesc alias)
-                                { return alias.first; })));
+                     context.aliases().flatten_aliases() |
+                     transform(std::mem_fn(&AliasRegistry::AliasDesc::first))));
     return {0, query.length(), std::move(candidates)};
 }
 

src/commands.cc

@@ -25,6 +25,8 @@
 #include "string.hh"
 #include "window.hh"
 
+#include <functional>
+
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
@@ -1508,8 +1510,7 @@ void context_wrap(const ParametersParser& parser, Context& context, Func func)
             // copy buffer list as we might be mutating the buffer list
             // in the loop.
             auto ptrs = BufferManager::instance() |
-                transform([](const std::unique_ptr<Buffer>& ptr)
-                          { return ptr.get(); });
+                transform(std::mem_fn(&std::unique_ptr<Buffer>::get));
             Vector<SafePtr<Buffer>> buffers{ptrs.begin(), ptrs.end()};
             for (auto buffer : buffers)
                 context_wrap_for_buffer(*buffer);

src/containers.hh

@@ -254,7 +254,7 @@ struct ConcatView
 {
     using ContainerIt1 = decltype(begin(std::declval<Container1>()));
     using ContainerIt2 = decltype(begin(std::declval<Container2>()));
-    using ValueType = typename ContainerIt1::value_type;
+    using ValueType = typename std::common_type<typename ContainerIt1::value_type, typename ContainerIt2::value_type>::type;
 
     struct Iterator : std::iterator<std::forward_iterator_tag, ValueType>
     {
@@ -265,7 +265,7 @@ struct ConcatView
             : m_it1(std::move(it1)), m_end1(std::move(end1)),
               m_it2(std::move(it2)) {}
 
-        decltype(*std::declval<ContainerIt1>()) operator*() { return is2() ? *m_it2 : *m_it1; }
+        ValueType operator*() { return is2() ? *m_it2 : *m_it1; }
         Iterator& operator++() { if (is2()) ++m_it2; else ++m_it1; return *this; }
         Iterator operator++(int) { auto copy = *this; ++*this; return copy; }
 

src/face_registry.cc

@@ -95,8 +95,7 @@ CandidateList FaceRegistry::complete_alias_name(StringView prefix,
                                                 ByteCount cursor_pos) const
 {
     return complete(prefix, cursor_pos,
-                    m_aliases | transform([](const AliasMap::value_type& v) -> const String&
-                                          { return v.first; }));
+                    m_aliases | transform(std::mem_fn(&AliasMap::value_type::first)));
 }
 
 FaceRegistry::FaceRegistry()

src/option_types.hh

@@ -32,7 +32,7 @@ struct option_type_name<Enum, typename std::enable_if<std::is_enum<Enum>::value>
     {
         constexpr StringView type = WithBitOps<Enum>::value ? "flags" : "enum";
         auto name = enum_desc(Enum{});
-        return type + "(" + join(name | transform([](const EnumDesc<Enum>& d) { return d.name; }), '|') + ")";
+        return type + "(" + join(name | transform(std::mem_fn(&EnumDesc<Enum>::name)), '|') + ")";
     }
 };
 

src/shell_manager.cc

@@ -235,9 +235,8 @@ String ShellManager::get_val(StringView name, const Context& context) const
 CandidateList ShellManager::complete_env_var(StringView prefix,
                                              ByteCount cursor_pos) const
 {
-    return complete(prefix, cursor_pos, m_env_vars |
-                    transform([](const EnvVarDesc& desc) -> const String&
-                              { return desc.str; }));
+    return complete(prefix, cursor_pos,
+                    m_env_vars | transform(std::mem_fn(&EnvVarDesc::str)));
 }
 
 }