How to make localized duration string? - c++

Question

I'm making an app in which I need to show duration string. A few examples:
1 hour 2 minutes left to break,
2 minutes 8 seconds left to break
For the moment I have a C++ function which for a given amount of seconds/milliseconds/minutes gives you a string:
wxString getTimeStr(int value,
ETimeUnit time_unit, // milliseconds or seconds or minutes or hours
wxString const & lang) // english or russian
It consists of lots of conditions depending on language, time units and existing value. Now I'm considering porting the app to other languages and it would be a bit painful to write c++ code for each new language. Is there a way to make that string using standard functions?
The app is written in C++ using wxWidgets and so far works only on Windows. I would prefer not to use platform-dependent functions, although it would be nice to know them.

Answer 1

You won't be able to do it perfectly without writing different code for different languages. For example, I bet your existing code doesn't allow to produce times like "5 minutes before half past threee" which are nevertheless used in (spoken) German. And even without going to such extends, consider that English "half past three" is translated to "half to four" actually.
So if using the official time is not enough (and if it is, look at wxLocale::GetInfo(wxLOCALE_TIME_FMT)), you will indeed need to write code to handle at least some languages specially.

Answer 2

I suggest splitting your function into two.
The first part would return the time remaining as a wxTimeSpan.
The second part 'translates' the wxTimeSpan into the required language and returns a string. This is the only part you need to change for each language.
For the sake of explanation, let's assume that
we only care about hours and minutes
Klingons like to see hours/mins
Vulcans like to see mins:hours
Russians have various forms of the word for minutes
Then your second function would be written something like this
// extract hours and residual minutes into CSV
wxString csv = theTimeSpan.Format("%H,%M);
// extract tokens for csv
wxString hours, mins
...
if( lang == "Klingon" ) {
return hours + "/" + mins
} else if ( lang == "Vulcan" ) {
return mins + ":" + hours
} else if ( lang == "Russian" ) {
wxString min_name;
switch( mins.ToLong() ) {
case 1: min_name = "---"; break;
...
}
return mins + " " + min_name;
}
Unfortunately you can NOT use Format to get an arbitrary 'time structure' because of an essential ambiguity in, for example, the number of hours in a time span. It can be either the total number of hours (for example, for a time span of 50 hours this would be 50) or just the hour part of the time span, which would be 2 in this case as 50 hours is equal to 2 days and 2 hours.
wxTimeSpan resolves this ambiguity in the following way: if there had been, indeed, the D format specified preceding the H, then it is interpreted as 2. Otherwise, it is 50. The same applies to all other format specifiers: if they follow a specifier of larger unit, only the rest part is taken, otherwise the full value is used.
So, you have to muck around with the csv tokens as shown in my code sample.

Answer 3

The traditional approach to the problem of localization is to build a map of label name -> label value and use place holders in the values.
In the code, you only reference the label name, and provide the values for the place holders
To port to another language, you just need to translate the map
Depending on the degree of sophistication you need, you might have a simple placeholder mechanism (snprintf-like), or one that allows a mini-language to build the value at runtime depending on simple parameters (for example, distinguishing between singular and plural).
In this example, it would be as simple as:
using LabelsType = std::map<LabelName, std::string>;
using LangToLabelsType = std::map<Language, LabelsType>;
Note: I advise an enum for the languages, rather than a plain string.
If you were on Linux I would recommend gettext, however I am unsure whether it works on Windows. Still, you can look it up and see how it works, it might help you.

Answer 4

Sometimes, it is better to make the program more technical rather than closer to natural language. I have also found myself in such situations (to make it looking really cool). It often was the case that the customer did not care. The information is sometimes much more important than its exact form.
A programmer should sometimes choose the tradeoffs -- a kind of meta-solution that is not related to the programming language/framework. In other words, you should weight the correctness of the solution and the correctness of the expectation.