[Boost-users] boost format problems

From: Navneet Dalal (Navneet.Dalal_at_[hidden])
Date: 2004-04-14 14:11:38

Hi

I decided to try boost::format for more compact and typesafe formatting of 
text. However, I am running into some problems. 

Problem 1
==============

The following line throws boost:bad_format_string exception.
std::cout << format("%|1| %|2$3|") % "Hello" % 3 << std::endl;

However, this one works
std::cout << format("%|1|") % "Hello" << std::endl;

All I want to do is use notation for printing character streams i.e. %|1| 
instead of %1%
Is this a bug or I am doing something wrong?

Problem 2
=============

How can I print a float such that it appends 0 for remaining precision digits.

For e.g. let us say I want to print 0.2 with 5 characters of overall length 
and till 3 digits of precision. Kind of output I am looking for is 0.200

One would expect that following command may work (as I am indicating left 
print, fill any remaining characters and till 3 digits of precision after 
decimal)
std::cout << format("#%|1$-05.03|#") % 0.2 << std::endl;
// however it prints 
#0.2  #

This command prints something like
std::cout << format("#%|1$05.03|#") % 0.2 << std::endl;
// it prints 
#000.2#

with C++ cout, I can print it like 
std::cout << '#' << std::left << std::setfill('0') <<  std::setw(5) << 
std::setprecision(3) << 0.2 << '#' << std::endl;

so on similar lines I wrote following line. it works, but it seems ugly to use 
group only for this
std::cout << format("#%|1$-05.3|#") % group(setfill('0'), 0.2) << std::endl;
// prints 
#0.200#

Does any one has any other suggestions?

regards
navneet