Rozental, Gennadiy wrote:
Here some more details:
1. What is your evaluation of the design?
Library trying to solve in fact trivial problem. Would it be presented as trivial function
Template<typename C> Foo( C const& c, std::string open, std::string close, std::string sep );
I may understand it.
This would mean that you would duplicate code for rendreing container types. Also, you are missing special formatting, e.g. wrapping open/close values around elements, e.g.: std::cout << formatob( vec, containerfmt( wrappedfmt().format( "<e>", "</e>" )).format( "<l>", "</l>" )); // output: <l><e>a</e><e>b</e></l> the indentation functionality that Volodya has expressed an interest in, and position-based output, e.g.: [0] John, [1] James, [2] Marina Also, the library should be usable on a standard stream. This is one of the key design aims. Can you do: std::cout << Foo( vec, "< ", " >", " :: " ); ? This requires returning an object that has << implemented. The mechanism for this is outlined in the standard by using *manipulators*. Thus, you would need that class to defer processing to the Foo function if you want to use your approach.
As to presented design - I see it as unnecessary complicated. And in many cases simply incorrect. Library does not follow standard practice as to wide char support.
I am addressing these issues. See my other discussions for details.
Interfaces seem confusing and error prone. Decoration model seems too simple to warrant so much trouble as reusable library. Maybe more powerful/flexible solution should be considered.
I have been reshaping the decoration model and have commented on it elsewhere.
2. What is your evaluation of the implementation?
In most part I either don't understand or don't like it. IMO simple task library trying to solve shouldn't require that much code. Simple overloading base solution should've done the trick.
This does not allow for flexibility to add indenting, wrapped data, etc.
4. What is your evaluation of the potential usefulness of the library?
Now to the most important: why would I ever want to use library like this?
We have already: std::ostream boost::format boost::serailization
In what scenario I would use this library?
But you can't do: std::vector< int > vec; std::cout << vec; // oops! no operator << defined for vectors.
I most definitely wouldn't want to repeat all this formatting every time I need to output my vector.
If you want [ a, b, c, d ] style output, you don't. The extra machinery is used to customize this. Also, you can save a format object, e.g.: // old style containerfmt_t< char, pairfmt_t< char > > myformat = containerfmt( pairfmt().format( " = " )).format( "<< ", "
" );
std::cout << formatob( vec, myformat ); // << ( a = 5 ), ( b = 7 ), ...
std::cout << formatob( lst, myformat ); // << ( i = 2.132 ), ( j = 3.14159 ), ... >> std::cin >> formatob( vec, myformat );
If I write output operation rarely - I would use explicit loop -it's more flexible anyway.
Depends what you are outputting. If the type contains nested containers, it can be more complex.
I wouldn't use this library for filtering - we will have iostreams library for that (If I am not mistaken).
This library does not provide filtering capabilities. What I was saying is that if you want to pretty print the data, it might be worth using Jonathan's library.
I wouldn't use this library for XML printing - why would I want to mention tag name twice?
You can use a wrapper format object: std::cout << formatob( vec, containerfmt( wrappedfmt().format( "<e>", "</e>" )).format( "<l>", "</l>" )); // output: <l><e>a</e><e>b</e></l> Regards, Reece _________________________________________________________________ Want to block unwanted pop-ups? Download the free MSN Toolbar now! http://toolbar.msn.co.uk/