Optionally re-allow passing variables to translation macros

Defining wxNO_REQUIRE_LITERAL_MSGIDS enables the old behaviour, where
translation macros do accept variables as string arguments.

The arguments nearly always need to be string literals, though, and
before defining this macro, it is advisable to check whether the code
should be fixed instead.

Author: lanurmi

docs/doxygen/mainpages/const_cpp.h

@@ -407,6 +407,15 @@ more details.
         the applications using the library to disable implicit
         conversions from and to <tt>const char*</tt> in wxString class.
         Support for this option appeared in wxWidgets 3.1.4.}
+@itemdef{wxNO_REQUIRE_LITERAL_MSGIDS,
+        this symbol is not defined by wxWidgets itself, but can be defined by
+        the applications using the library to allow variables as string arguments to
+        translation macros such as _() and wxPLURAL. The default since wxWidgets
+        3.3.0 is to allow only string literals.
+        Note that passing string variables as arguments to translation macros is
+        likely to be a bug, and does not produce the expected results. If you
+        feel you need to define this macro, you should first consider whether
+        your code is doing the right thing.}
 @itemdef{WXMAKINGDLL_XXX,
         used internally and defined when building the
         library @c XXX as a DLL; when a monolithic wxWidgets build is used only a

include/wx/translation.h

@@ -48,16 +48,16 @@ using wxTranslationsHashMap = std::unordered_map<wxString, wxString>;
     #define _(s)                               wxUnderscoreWrapper((s))
 #endif
 
-#define wxPLURAL(sing, plur, n)                wxwxPluralWrapper((sing), (plur), n)
+#define wxPLURAL(sing, plur, n)                wxPluralWrapper((sing), (plur), n)
 
 // wx-specific macro for translating strings in the given context: if you use
 // them, you need to also add
 // --keyword="wxGETTEXT_IN_CONTEXT:1c,2" --keyword="wxGETTEXT_IN_CONTEXT_PLURAL:1c,2,3"
 // options to xgettext invocation.
 #define wxGETTEXT_IN_CONTEXT(c, s) \
-    wxwxGettextInContextWrapper((c), (s))
+    wxGettextInContextWrapper((c), (s))
 #define wxGETTEXT_IN_CONTEXT_PLURAL(c, sing, plur, n) \
-    wxwxGettextInContextPluralWrapper((c), (sing), (plur), (n))
+    wxGettextInContextPluralWrapper((c), (sing), (plur), (n))
 
 // another one which just marks the strings for extraction, but doesn't
 // perform the translation (use -kwxTRANSLATE with xgettext!)
@@ -335,6 +335,9 @@ inline const wxString& wxGetTranslation(const char *str1,
 
 #endif // wxNO_IMPLICIT_WXSTRING_ENCODING
 
+namespace wxTransImplStrict
+{
+
 // Wrapper functions that only accept string literals as arguments,
 // not variables, not char* pointers.
 template<size_t N>
@@ -348,7 +351,7 @@ const wxString &wxUnderscoreWrapper(const char (&msg)[N])
 }
 
 template<size_t M, size_t N>
-const wxString& wxwxPluralWrapper(const char(&msg)[M], const char(&plural)[N], int count)
+const wxString &wxPluralWrapper(const char (&msg)[M], const char (&plural)[N], int count)
 {
 #ifndef wxNO_IMPLICIT_WXSTRING_ENCODING
     return wxGetTranslation(msg, plural, count);
@@ -358,7 +361,7 @@ const wxString& wxwxPluralWrapper(const char(&msg)[M], const char(&plural)[N], i
 }
 
 template<size_t M, size_t N>
-const wxString& wxwxGettextInContextWrapper(const char(&ctx)[M], const char(&msg)[N])
+const wxString &wxGettextInContextWrapper(const char (&ctx)[M], const char (&msg)[N])
 {
 #ifndef wxNO_IMPLICIT_WXSTRING_ENCODING
     return wxGetTranslation(msg, wxString(), ctx);
@@ -368,7 +371,7 @@ const wxString& wxwxGettextInContextWrapper(const char(&ctx)[M], const char(&msg
 }
 
 template<size_t L, size_t M, size_t N>
-const wxString &wxwxGettextInContextPluralWrapper(const char (&ctx)[L],
+const wxString &wxGettextInContextPluralWrapper(const char (&ctx)[L],
                                                   const char (&msg)[M],
                                                   const char (&plural)[N], int count)
 {
@@ -380,6 +383,60 @@ const wxString &wxwxGettextInContextPluralWrapper(const char (&ctx)[L],
 #endif
 }
 
+} // namespace wxTransImplStrict
+
+namespace wxTransImplTraditional
+{
+
+// Wrapper functions that accept both string literals and variables
+// as arguments.
+inline const wxString &wxUnderscoreWrapper(const wxString& msg)
+{
+#ifndef wxNO_IMPLICIT_WXSTRING_ENCODING
+    return wxGetTranslation(msg);
+#else
+    return wxGetTranslation(wxASCII_STR(msg));
+#endif
+}
+
+inline const wxString &wxPluralWrapper(const wxString& msg, const wxString& plural, int count)
+{
+#ifndef wxNO_IMPLICIT_WXSTRING_ENCODING
+    return wxGetTranslation(msg, plural, count);
+#else
+    return wxGetTranslation(wxASCII_STR(msg), wxASCII_STR(plural), count);
+#endif
+}
+
+inline const wxString &wxGettextInContextWrapper(const wxString& ctx, const wxString& msg)
+{
+#ifndef wxNO_IMPLICIT_WXSTRING_ENCODING
+    return wxGetTranslation(msg, wxString(), ctx);
+#else
+    return wxGetTranslation(wxASCII_STR(msg), wxString(), wxASCII_STR(ctx));
+#endif
+}
+
+inline const wxString &wxGettextInContextPluralWrapper(const wxString& ctx,
+                                                  const wxString&msg,
+                                                  const wxString&plural, int count)
+{
+#ifndef wxNO_IMPLICIT_WXSTRING_ENCODING
+    return wxGetTranslation(msg, plural, count, wxString(), ctx);
+#else
+    return wxGetTranslation(wxASCII_STR(msg), wxASCII_STR(plural), count,
+                            wxString(), wxASCII_STR(ctx));
+#endif
+}
+
+} // namespace wxTransImplTraditional
+
+#ifdef wxNO_REQUIRE_LITERAL_MSGIDS
+using namespace wxTransImplTraditional;
+#else
+using namespace wxTransImplStrict;
+#endif
+
 #else // !wxUSE_INTL
 
 // the macros should still be defined - otherwise compilation would fail