Gettext literal

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

@@ -45,30 +45,19 @@ using wxTranslationsHashMap = std::unordered_map<wxString, wxString>;
 // --keyword="_" --keyword="wxPLURAL:1,2" options
 // to extract the strings from the sources)
 #ifndef WXINTL_NO_GETTEXT_MACRO
-#ifndef wxNO_IMPLICIT_WXSTRING_ENCODING
-    #define _(s)                               wxGetTranslation((s))
-#else
-    #define _(s)                               wxGetTranslation(wxASCII_STR(s))
-#endif
+    #define _(s)                               wxUnderscoreWrapper((s))
 #endif
 
-#define wxPLURAL(sing, plur, n)                wxGetTranslation((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.
-#ifndef wxNO_IMPLICIT_WXSTRING_ENCODING
 #define wxGETTEXT_IN_CONTEXT(c, s) \
-    wxGetTranslation((s), wxString(), c)
+    wxGettextInContextWrapper((c), (s))
 #define wxGETTEXT_IN_CONTEXT_PLURAL(c, sing, plur, n) \
-    wxGetTranslation((sing), (plur), n, wxString(), c)
-#else
-#define wxGETTEXT_IN_CONTEXT(c, s) \
-    wxGetTranslation(wxASCII_STR(s), wxString(), wxASCII_STR(c))
-#define wxGETTEXT_IN_CONTEXT_PLURAL(c, sing, plur, n) \
-    wxGetTranslation(wxASCII_STR(sing), wxASCII_STR(plur), n, wxString(), wxASCII_STR(c))
-#endif
+    wxGettextInContextPluralWrapper((c), (sing), (plur), (n))
 
 // another one which just marks the strings for extraction, but doesn't
 // perform the translation (use -kwxTRANSLATE with xgettext!)
@@ -344,8 +333,93 @@ inline const wxString& wxGetTranslation(const char *str1,
                             wxString(context, conv));
 }
 
+    #define wxTRANS_INPUT_STR(s) wxASCII_STR(s)
+#else
+    #define wxTRANS_INPUT_STR(s) s
 #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>
+const wxString& wxUnderscoreWrapper(const char (&msg)[N])
+{
+    return wxGetTranslation(wxTRANS_INPUT_STR(msg));
+}
+
+template<size_t M, size_t N>
+const wxString& wxPluralWrapper(const char (&msg)[M],
+                                const char (&plural)[N],
+                                int count)
+{
+    return wxGetTranslation(wxTRANS_INPUT_STR(msg), wxTRANS_INPUT_STR(plural),
+                            count);
+}
+
+template<size_t M, size_t N>
+const wxString& wxGettextInContextWrapper(const char (&ctx)[M],
+                                          const char (&msg)[N])
+{
+    return wxGetTranslation(wxTRANS_INPUT_STR(msg), wxString(),
+                            wxTRANS_INPUT_STR(ctx));
+}
+
+template<size_t L, size_t M, size_t N>
+const wxString& wxGettextInContextPluralWrapper(const char (&ctx)[L],
+                                                const char (&msg)[M],
+                                                const char (&plural)[N],
+                                                int count)
+{
+    return wxGetTranslation(wxTRANS_INPUT_STR(msg), wxTRANS_INPUT_STR(plural),
+                            count, wxString(), wxTRANS_INPUT_STR(ctx));
+}
+
+} // namespace wxTransImplStrict
+
+namespace wxTransImplCompatible
+{
+
+// Wrapper functions that accept both string literals and variables
+// as arguments.
+inline const wxString& wxUnderscoreWrapper(const char *msg)
+{
+    return wxGetTranslation(wxTRANS_INPUT_STR(msg));
+}
+
+inline const wxString& wxPluralWrapper(const char *msg,
+                                       const char *plural,
+                                       int count)
+{
+    return wxGetTranslation(wxTRANS_INPUT_STR(msg), wxTRANS_INPUT_STR(plural),
+                            count);
+}
+
+inline const wxString& wxGettextInContextWrapper(const char *ctx,
+                                                 const char *msg)
+{
+    return wxGetTranslation(wxTRANS_INPUT_STR(msg), wxString(),
+                            wxTRANS_INPUT_STR(ctx));
+}
+
+inline const wxString& wxGettextInContextPluralWrapper(const char *ctx,
+                                                       const char *msg,
+                                                       const char *plural,
+                                                       int count)
+{
+    return wxGetTranslation(wxTRANS_INPUT_STR(msg), wxTRANS_INPUT_STR(plural),
+                            count, wxString(), wxTRANS_INPUT_STR(ctx));
+}
+
+} // namespace wxTransImplCompatible
+
+#ifdef wxNO_REQUIRE_LITERAL_MSGIDS
+using namespace wxTransImplCompatible;
+#else
+using namespace wxTransImplStrict;
+#endif
+
 #else // !wxUSE_INTL
 
 // the macros should still be defined - otherwise compilation would fail

interface/wx/translation.h

@@ -465,9 +465,11 @@ class wxMsgCatalog
 ///@{
 
 /**
-    This macro is identical to _() but for the plural variant of
+    This macro is similar to _() but for the plural variant of
     wxGetTranslation().
 
+    The string arguments must be @em string @em literals.
+
     @return A const wxString.
 
     @header{wx/intl.h}
@@ -479,6 +481,8 @@ class wxMsgCatalog
 
     See the description of @c context argument of wxGetTranslation().
 
+    The arguments must be @em string @em literals.
+
     @see wxGETTEXT_IN_CONTEXT_PLURAL()
 
     @since 3.1.1
@@ -488,6 +492,8 @@ class wxMsgCatalog
 /**
     Similar to wxPLURAL() but translates the string in the given context.
 
+    The string arguments must be @em string @em literals.
+
     See the description of @c context argument of wxGetTranslation().
 
     @see wxGETTEXT_IN_CONTEXT()
@@ -567,7 +573,8 @@ class wxMsgCatalog
     If @a domain is specified then only that domain/catalog is searched for a
     matching string.  As this function is used very often, an alternative (and
     also common in Unix world) syntax is provided: the _() macro is defined to
-    do the same thing as wxGetTranslation().
+    do nearly the same thing as wxGetTranslation(), with the exception that
+    the argument to _() must be a string literal.
 
     If @a context is not empty (notice that this argument is only available
     starting from wxWidgets 3.1.1), item translation is looked up in the
@@ -633,7 +640,7 @@ const wxString& wxGetTranslation(const wxString& string,
 
     @header{wx/intl.h}
 */
-const wxString& _(const wxString& string);
+#define _(string)
 
 ///@}