[boost] outputformatters - using just one decorator string

From: John Torjo (john.lists_at_[hidden])
Date: 2004-09-21 11:26:56

Hi Reece,

This just popped into my head. A lot of confusion seems to come from how 
you pass decorators. What I'm trying to say is that it can be very 
difficult to get the decorator strings right (especially for more 
complex things like XML) from the first time.

I would suggest every formatter takes only one string which parses and 
finds all decorators itself.
Each formatter will have one or more escape sequences which it uses to 
find the decorators.

Something like:

// in this case, '%' is used for identifying an element
//                '*' is to mean "leave default" (don't change)

std::vector<int> v;
// equivalent to your "[ ", ", ", " ]"
std::cout << formatob(v, "[ %, % ]");

// eq. to "<< ", " | ", " >>"
std::cout << formatob(v, "<< % | %  >>");

// set only open/close decorators
std::cout << formatob(v, "<< %*%  >>");

// sets only the separator
std::cout << formatob(v, "*% | %*");

// for pair - you have "%1"  and "%2"
std::vector< std::pair<int,long> > vp;
// write XML
std::cout << formatob(vp,
    containerfmt("<elem> % </elem><elem> % </elem>",
     pairfrt("<int>%1</int><long>%2</long>")));

How's that?

Best,
John

-- 
John Torjo
-- john_at_[hidden]
Contributing editor, C/C++ Users Journal
-- "Win32 GUI Generics" -- generics & GUI do mix, after all
-- http://www.torjo.com/win32gui/
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