A header-only library for C++(0x) that allows automagic pretty-printing of any container.

I'm looking to use this library in a GPLv3+ project, but I can't find a license on this code. Would it be possible that you make explicit the license it is under (or point me to where this is done)?

It would be better to select an existing license, like CC0 for the closest one can legally get to releasing into public domain in many jurisdictions, zlib license for a permissive Free/Open Source license, or GNU GPLv3 for a strong copyleft Free/Open Source license. This is preferable to a statement such as "You can use this however you want" -- that statement is ambiguous in to whom the license refers, so it might actually not be a Free/Open Source license!

Use clang++ or g++ with -std=c++11 get an error::

/tmp/prettyprint.hpp:207:17: error: call to 'begin' is ambiguous
            if (begin(_container) != end(_container))
                ^~~~~

Here is a simple patch to fix this:

--- prettyprint_old.hpp 2012-07-13 10:37:02.521452515 +0800
+++ prettyprint.hpp 2012-07-13 10:39:05.604789149 +0800
@@ -204,8 +204,9 @@
             if (delimiters_type::values.prefix != NULL)
                 stream << delimiters_type::values.prefix;

-            if (begin(_container) != end(_container))
-            for (TIter it = begin(_container), it_end = end(_container); ; )
+            if (::pretty_print::begin(_container) != ::pretty_print::end(_container))
+            for (TIter it = ::pretty_print::begin(_container), 
+                       it_end = ::pretty_print::end(_container); ; )
             {
                 stream << *it;

prettyprint98.hpp generates this with GCC 4.7 and -Wshadow:

prettyprint98.hpp: In constructor 'pretty_print::custom_delims_wrapper<T, Delims>::custom_delims_wrapper(const T&)':
prettyprint98.hpp:241:44: warning: declaration of 't' shadows a member of 'this' [-Wshadow]
prettyprint98.hpp: In member function 'std::ostream& pretty_print::custom_delims_wrapper<T, Delims>::stream(std::ostream&)':
prettyprint98.hpp:244:9: warning: declaration of 'stream' shadows a member of 'this' [-Wshadow]
prettyprint98.hpp: In member function 'std::wostream& pretty_print::custom_delims_wrapper<T, Delims>::stream(std::wostream&)':
prettyprint98.hpp:248:9: warning: declaration of 'stream' shadows a member of 'this' [-Wshadow]

As -Wshadow is a very useful warning and I would like my programs to be warning-free, I kindly ask to fix this :-)

Apparently, it is not possible to define custom delimiters for tuples.

#include <iostream>
#include <tuple>
#include <prettyprint/prettyprint.hpp>

struct delims { static const pretty_print::delimiters_values<char> values;};
const pretty_print::delimiters_values<char> delims::values = {"<", "," ">"};

int main() {

    auto t = std::make_tuple(12.5, 4, "hello");
    std::cout << pretty_print::custom_delims<delims>(t) << std::endl;
}

Compiled with:

clang++ -std=c++11 -stdlib=libc++ pretty.cpp -o pretty

compiler:

$ clang --version
Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)
Target: x86_64-apple-darwin13.1.0
Thread model: posix

Error:

/usr/local/include/prettyprint/prettyprint.hpp:205:27: error: no matching
      function for call to 'begin'

Thanks, Ilio.

Having a look to your code I see you add to namaspace std the following: inline basic_ostream<TChar, TCharTraits> & operator<<(basic_ostream<TChar, TCharTraits> & stream, const tuple<TUPLE_ARGS> & value)

Is this legal c++? because of: [C++11: 17.6.4.2.1/1]: The behavior of a C++ program is undefined if it adds declarations or definitions to namespace std or to a namespace within namespace std unless otherwise specified. A program may add a template specialization for any standard library template to namespace std only if the declaration depends on a user-defined type and the specialization meets the standard library requirements for the original template and is not explicitly prohibited.

this is not legal. I'm missing something? Anyway, thank a lot for this nice piece of code.

1. Added function need_qoute, that returns true if it's argument is a string (this behavior can be turned off by #define DONT_QUOTE_STRINGS before including this file).
2. Changed output for containers, pairs and tupels. Now they call need_qoute and add quotes if need

This code:

#include <iostream>
#include <prettyprint.hpp>
int main() {
    std::wstring ws = L"Hi";
    std::cout << "ws = " << ws << std::endl;
}

prints:

ws = [72, 105]

instead of producing compiler error (as it do without second include)

I am attempting to build this with

Apple LLVM version 4.2 (clang-425.0.24) (based on LLVM 3.2svn)
Target: x86_64-apple-darwin12.4.0                             
Thread model: posix                                           

The incantation is

clang++ -g -O3 -std=c++0x -stdlib=libc++ <...>

(use of -O2 or -O0 did not alleviate the problem)

With GCC 4.7.2 (flags: -Wall -Wextra -pedantic -std=c++11 -O2) and the latest prettyprint.hpp I get

prettyprint.hpp:89:48: error: 'valarray' is not a member of 'std'
prettyprint.hpp:89:48: error: 'valarray' is not a member of 'std'
prettyprint.hpp:89:64: error: template argument 1 is invalid
prettyprint.hpp:89:65: error: expected unqualified-id before '>' token
prettyprint.hpp:89:97: warning: extra ';' [-pedantic]

The header needs to #include <valarray>.

The foward declaration of set and multiset in prettyprint98.hpp leads to undefined behaviour. See the following discussion: https://groups.google.com/forum/?fromgroups=#!topic/comp.lang.c++.moderated/XBKFjGNquDM

Please remove the forward declarations and just include . I think the impact on compilation speed is negligible, too.

(This is a real world issue since I can't compile prettyprint together with boost/archive due to that.)

I am a beginner in language and I found some problems Since we already have

https://github.com/louisdx/cxx-prettyprint/blob/master/prettyprint.hpp#L107

Can I delete this?

https://github.com/louisdx/cxx-prettyprint/blob/master/prettyprint.hpp#L160

Is it redundant？I have try and no error find.

The following code fails to compile with the Intel Compiler icc (ICC) 2021.1 Beta 20200827: gcc and clang compile this code without problems.

// ex.cpp
#include<iostream>
#include<vector>
#include<utility>

#include "prettyprint.hpp"

int main() {
  std::vector<std::pair<int, std::vector<int>>> v;
  std::cout << v << std::endl;
  return 1;
}

I ran the code using a docker container based on the official intel image intel/oneapi-hpckit. The following is the slightly cleaned-up output of icc including the setup of the docker container.

> ls
ex.cpp
prettyprint.hpp

> docker run --rm -it -v$(pwd):/src:ro intel/oneapi-hpckit

# icc -I /src/ /src/ex.cpp 
/src/prettyprint.hpp(152): error: invalid partial specialization -- class "pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters>::printer<std::pair<int, std::vector<int, std::allocator<int>>>> [with T=std::vector<int, std::allocator<int>>, TChar=char, TCharTraits=std::char_traits<char>, TDelimiters=pretty_print::delimiters<std::vector<int, std::allocator<int>>, char>]" is already fully specialized
  struct print_container_helper<T, TChar, TCharTraits, TDelimiters>::printer<std::pair<T1, T2>> {
                                                                     ^
          detected during:
            instantiation of class "pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters> [with T=std::vector<int, std::allocator<int>>, TChar=char, TCharTraits=std::char_traits<char>, TDelimiters=pretty_print::delimiters<std::vector<int, std::allocator<int>>, char>]" at line 475
            instantiation of "std::enable_if<pretty_print::is_container<T>::value, std::basic_ostream<TChar, TCharTraits> &>::type std::operator<<(std::basic_ostream<TChar, TCharTraits> &, const T &) [with T=std::vector<int, std::allocator<int>>, TChar=char, TCharTraits=std::char_traits<char>]" at line 160

            instantiation of "void pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters>::printer<std::pair<T1, T2>>::print_body(const std::pair<T1, T2> &, pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters>::printer<std::pair<T1, T2>>::ostream_type &) [with T=std::pair<int, std::vector<int, std::allocator<int>>>, TChar=char, TCharTraits=std::char_traits<char>, TDelimiters=pretty_print::delimiters<std::pair<int, std::vector<int, std::allocator<int>>>, char>, T1=int, T2=std::vector<int, std::allocator<int>>]" at line 138
            instantiation of "void pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters>::operator()(pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters>::ostream_type &) const [with T=std::pair<int, std::vector<int, std::allocator<int>>>, TChar=char, TCharTraits=std::char_traits<char>, TDelimiters=pretty_print::delimiters<std::pair<int, std::vector<int, std::allocator<int>>>, char>]" at line 211
            instantiation of "std::basic_ostream<TChar, TCharTraits> &pretty_print::operator<<(std::basic_ostream<TChar, TCharTraits> &, const pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters> &) [with T=std::pair<int, std::vector<int, std::allocator<int>>>, TChar=char, TCharTraits=std::char_traits<char>, TDelimiters=pretty_print::delimiters<std::pair<int, std::vector<int, std::allocator<int>>>, char>]" at line 475
            instantiation of "std::enable_if<pretty_print::is_container<T>::value, std::basic_ostream<TChar, TCharTraits> &>::type std::operator<<(std::basic_ostream<TChar, TCharTraits> &, const T &) [with T=std::pair<int, std::vector<int, std::allocator<int>>>, TChar=char, TCharTraits=std::char_traits<char>]" at line 116

            instantiation of "void pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters>::printer<U>::print_body(const U &, pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters>::ostream_type &) [with T=std::vector<std::pair<int, std::vector<int, std::allocator<int>>>, std::allocator<std::pair<int, std::vector<int, std::allocator<int>>>>>, TChar=char, TCharTraits=std::char_traits<char>, TDelimiters=pretty_print::delimiters<std::vector<std::pair<int, std::vector<int, std::allocator<int>>>, std::allocator<std::pair<int, std::vector<int, std::allocator<int>>>>>, char>, U=std::vector<std::pair<int, std::vector<int, std::allocator<int>>>, std::allocator<std::pair<int, std::vector<int, std::allocator<int>>>>>]" at line 138
            instantiation of "void pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters>::operator()(pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters>::ostream_type &) const [with T=std::vector<std::pair<int, std::vector<int, std::allocator<int>>>, std::allocator<std::pair<int, std::vector<int, std::allocator<int>>>>>, TChar=char, TCharTraits=std::char_traits<char>, TDelimiters=pretty_print::delimiters<std::vector<std::pair<int, std::vector<int, std::allocator<int>>>, std::allocator<std::pair<int, std::vector<int, std::allocator<int>>>>>, char>]" at line 211
            instantiation of "std::basic_ostream<TChar, TCharTraits> &pretty_print::operator<<(std::basic_ostream<TChar, TCharTraits> &, const pretty_print::print_container_helper<T, TChar, TCharTraits, TDelimiters> &) [with T=std::vector<std::pair<int, std::vector<int, std::allocator<int>>>, std::allocator<std::pair<int, std::vector<int, std::allocator<int>>>>>, TChar=char, TCharTraits=std::char_traits<char>, TDelimiters=pretty_print::delimiters<std::vector<std::pair<int, std::vector<int, std::allocator<int>>>, std::allocator<std::pair<int, std::vector<int, std::allocator<int>>>>>, char>]" at line 475
            instantiation of "std::enable_if<pretty_print::is_container<T>::value, std::basic_ostream<TChar, TCharTraits> &>::type std::operator<<(std::basic_ostream<TChar, TCharTraits> &, const T &) [with T=std::vector<std::pair<int, std::vector<int, std::allocator<int>>>, std::allocator<std::pair<int, std::vector<int, std::allocator<int>>>>>, TChar=char, TCharTraits=std::char_traits<char>]" at line 9 of "/src/ex.cpp"

compilation aborted for /src/ex.cpp (code 2)

I was trying to compile ppdemo.cpp with the latest version of VS 2017 (ver. 15.9.14), and got the following internal compiler error:

D:\Work_OSS\cxx-prettyprint>cl /EHsc ppdemo.cpp
Microsoft (R) C/C++ Optimizing Compiler Version 19.16.27032.1 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

ppdemo.cpp
d:\work_oss\cxx-prettyprint\prettyprint.hpp(62): fatal error C1001: An internal error has occurred in the compiler.
(compiler file 'd:\agent\_work\2\s\src\vctools\compiler\cxxfe\sl\p1\c\types.c', line 4563)
 To work around this problem, try simplifying or changing the program near the locations listed above.
Please choose the Technical Support command on the Visual C++
 Help menu, or open the Technical Support help file for more information
d:\work_oss\cxx-prettyprint\prettyprint.hpp(69): note: see reference to class template instantiation 'pretty_print::detail::has_begin_end<T>' being compiled

This PR changes has_const_iterator to additionally check

1. for std::iterator_traits to exist and
2. for its return_type to be non-void.

This catches additional cases and is compatible with the iterator rules up to C++20.

Motivation for this change is the incompatibility with the new iterator interface of Eigen3, which sets const_iterator = void for non-vector types. This breaks prettyprint.

This adds support for std::optional. It uses a feature-test macro to determine whether the compiler supports that. I added a fourth delimiter type in order to print "nullopt" when the optional is empty.