C++ library to convert [almost] any type to a string

to_stream is C++ header only library designed to output almost any type to a std::o[w]stream.
Main purpouse of the library is output arbitary variable/expression to a log file/console.

Examples

int aVar = 10;

Utils::Manip::to_stream(std::cout, aVar);

Output:

10

or using to_stream_helper.hpp:

int aVar = 10;

std::cout << LOG_VAR(aVar);

Output:

aVar<10>

Not really exciting, but you can change type of aVar without touching anything else:

int bool = true;

std::cout << LOG_VAR(aVar);

Output:

aVar<true>

or

int aVar[] = {1, 2, 3, 4, 5, 6};

std::cout << LOG_VAR(aVar);

Output:

aVar<[6](1, 2, 3, 4, 5, 6)>

Supported types

At the moment to_stream supports following types out of a box:

• builtin arithmetic types (char, unsigned, int, float, etc)
• unsigned char (outputs as unsigned)
• builtin (C style) arrays
• STL data types and containers/adapters:
  • std::pair
  • std::vector
  • std::list
  • std::queue
  • std::priority_queue
  • std::dequeue
  • std::stack
  • std::map
  • std::set
  • std::multimap
  • std::multiset
  • std::string
• boost data types/containers:
  • boost::unordered::unordered_set
  • boost::optional
  • boost::array
• any type which has an output operator (operator<<()) defined
• any STL-like container
• any type which has to_stream() method defined
• any type which has to_string() method defined

Output is recursive. It means to_stream can output variables of quite complex types:

std::vector<std::pair<int, boost::optional<std::string> > > aVar;
aVar.push_back(std::make_pair(1, "one"));
aVar.push_back(std::make_pair(2, "two"));
aVar.push_back(std::make_pair(3, boost::optional<std::string>()));

std::cout << LOG_VAR(aVar);

Output:

aVar<[3]((1, one), (2, two), (3, --))>

Dependencies

to_stream depends on following Boost libraries:

• type_traits
• utility (enable_if)
• MPL
• optional

Algorithm

to_stream using following algorithm to output type T to a stream:

• if T is bool to_stream' output trueorfalse`.
• if T is unsigned char to_stream' output value **casted** to unsigned int`.
• if T is std::pair to_stream' output value as (first, second). to_streamcalls itself to outputfirstandsecond`. This allows to output complex types.
• if T is boost::optional `to_stream' output "--' if it is not initialized or calls itself to output the value.
• if T has an output operator (std::basic_ostream<CharT, Traits>& operator<<(std::basic_ostream<CharT, Traits> &, const T&)) to_stream uses the output operator.
• if T looks like STL container (has T::const_iterator and T::value_type defined) or T is builtin (C style) array to_stream loops thru elements of T and ouput them to a stream (in format [N](E1, E2, .., En)). to_stream calls itself to output each element. This allows to output complex types.
• if T is STL adapter (std::stack, std::dequeue, std::queue or std::priority_queue) to_stream output element of the adapter using the same format as STL container.
• if T has to_stream method (std::basic_ostream<CharT, Traits>& to_stream(std::basic_ostream<CharT, Traits>&) const) to_stream uses the method.
• if T has to_string method (std::string to_string() const) to_stream uses the method.

Copyright

This library is available under the Boost Software License.
Copyright (C) 2013 Dmitriy Maksimov.
Distributed under the Boost Software License, Version 1.0. (See Accompanying File LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)