Since raw use of the iomanip stream modifiers is a) verbose and b) error prone (sticky vs. non-sticky, etc.), for user defined types, all that stuff can be hidden in the default
operator<< ... as shown here, for example.
However, when formatting built-in types (even from within a user defined operator), it would be much more convenient (IMHO) to use an approach similar to
std::quoted(beware C++14), where the data is wrapped in a function call that returns a temporary object that sets + resets the appropriate flags.
Essentially, instead of writing:
std::cout << std::setprecision(2) << std::fixed << 1.23456 << "\n";
you would hypothetically write:
using namespace shorter;
std::cout << precis(2, fixed(1.234556)) << "\n";
As the example shows, combination of flags could get tricky and I'm sure the devil is in the details, so I was wondering whether there is any prior art / exiting helper library that tries to address "chevron hell". :-)
Specifically, this question is not about any kind of "type safe format string" (like Boost.Format offers).
I'm also not asking for a "best" library, I'm asking about any library doing this for normal ostreams. (Because I was not able to find any.)
For example, the write API of C++ Format does something like this, but it doesn't do it for std::iostreams, but for the library's "stream" type:
out << pad(hex(0xcafe), 8, '0');