What's the Q_DECLARE_TR_FUNCTIONS equivalent for namespaces?

Justin Sayne

Assuming I want to change this:

class Utils
{
  Q_DECLARE_TR_FUNCTIONS( Utils );

  static void foo1();
  static void foo2();
  static void foo3();
};

into what is really more reasonable:

namespace Utils
{
  // What's the equivalent here to declare a translation context for my utility namespace?
  // Q_DECLARE_TR_FUNCTIONS( Utils ); ???

  void foo1();
  void foo2();
  void foo3();
}

kshegunov

@Justin-Sayne
Hello,
Doesn't it work to simply use QObject::tr in this case? As far as I can tell Q_DECLARE_TR_FUNCTIONS only aliases the aforementioned function with a proper context ...

PS:
The Q_DECLARE_TR_FUNCTIONS macro is defined as:

#define Q_DECLARE_TR_FUNCTIONS(context) \
public: \
    static inline QString tr(const char *sourceText, const char *disambiguation = Q_NULLPTR, int n = -1) \
        { return QCoreApplication::translate(#context, sourceText, disambiguation, n); } \
    QT_DECLARE_DEPRECATED_TR_FUNCTIONS(context) \
private:

Kind regards.

Justin Sayne

@kshegunov
Yes, but that's what I mean. By using contexts, this will also show up nicely ordered in QtLinguist later on, right? If I lose the ability to specify contexts for all namespaces, won't they all end up in global space later on and making translation a lot more cluttered than using a class with static utility methods and keeping the ability to wrap it inside a translation context?

kshegunov

@Justin-Sayne said:

Yes, but that's what I mean. By using contexts, this will also show up nicely ordered in QtLinguist later on, right? If I lose the ability to specify contexts for all namespaces, won't they all end up in global space later on and making translation a lot more cluttered than using a class with static utility methods and keeping the ability to wrap it inside a translation context?

I guess so, but you could alias the function in a similar fashion. For example you could have a tr() function in the namespace that specifies the context as the namespace name. Or you could even make a macro for it (it's basically the same only the access specifiers are stripped):

#define Q_DECLARE_NAMESPACE_TR(context) \
    inline QString tr(const char *sourceText, const char *disambiguation = Q_NULLPTR, int n = -1) \
    { return QCoreApplication::translate(#context, sourceText, disambiguation, n); }

Then use it in your namespace:

namespace MyNamespace
{
    Q_DECLARE_NAMESPACE_TR(MyNamespace)

    int someFunction();
}

Kind regards.

Justin Sayne

@kshegunov
Yes, that's actually a great solution. Should have thought of it myself. :D

Stuhalsky Alex

@kshegunov
Important addition.
If there is a struct|class MyType inside this namespace MyNamespace in which Q_DECLARE_NAMESPACE_TR(MyNamespace) macro used, all direct call of tr() function inside MyType methods will deduct context as MyNamespace::MyType. Not just MyNamespace. That's why translation may not work.

Don't forget to call tr() inside this namespace like MyNamespace::tr() to avoid such context issue.