Add an example of using GENERATE(table())

[richardash1981]

Description

There are some examples on issue #850 of using this feature, but they are not easily found from the documentation. Adding them here as an example makes them more findable and ensures they keep working if the API changes.

GitHub Issues

[richardash1981]

That's weird. It failed on the AMD 64 / Linux / Xenial COMPILER='clang++-3.8' EXAMPLES=1 COVERAGE=1 EXTRAS=1 run in Travis.
That's fair enough in that my tests were AMD 64 / Linux / GCC 9.3.0.
Clang versions are confusing me, because the one I have available is clang++ 9.0.1. Clang 3.8 is a really old version by now?

This is the error compiling the example

[ 26%] Building CXX object examples/CMakeFiles/302-Gen-Table.dir/302-Gen-Table.cpp.o
/home/travis/build/catchorg/Catch2/examples/302-Gen-Table.cpp:31:59: error: no
      matching function for call to 'table'
  ...expected_output) = GENERATE( table<std::string, size_t>({
                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~
/home/travis/build/catchorg/Catch2/single_include/catch2/catch.hpp:4107:97: note: 
      expanded from macro 'GENERATE'
  ...namespace Catch::Generators; return makeGenerators( __VA_ARGS__ ); } ) /...
                                                         ^~~~~~~~~~~
/home/travis/build/catchorg/Catch2/single_include/catch2/catch.hpp:4058:41: note: 
      candidate function [with Ts = <std::__cxx11::basic_string<char>, unsigned
      long>] not viable: cannot convert initializer list argument to
      'std::tuple<std::__cxx11::basic_string<char>, unsigned long>'
    GeneratorWrapper<std::tuple<Ts...>> table( std::initializer_list<std...
                                        ^
/home/travis/build/catchorg/Catch2/examples/302-Gen-Table.cpp:31:49: error: no
      matching function for call to 'generate'
  ...expected_output) = GENERATE( table<std::string, size_t>({
                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/travis/build/catchorg/Catch2/single_include/catch2/catch.hpp:4105:5: note: 
      expanded from macro 'GENERATE'
    Catch::Generators::generate( INTERNAL_CATCH_STRINGIZE(INTERNAL_CATCH...
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/travis/build/catchorg/Catch2/single_include/catch2/catch.hpp:4089:10: note: 
      candidate template ignored: substitution failure [with L = (lambda at
      /home/travis/build/catchorg/Catch2/examples/302-Gen-Table.cpp:31:49)]:
      member reference base type 'typename add_rvalue_reference<void>::type'
      (aka 'void') is not a structure or union
  ...generate( StringRef generatorName, SourceLineInfo const& lineInfo, L const& generatorExpression ) -> decltype(std::declval<decltype(generatorExpression())>()....
     ^                                                                                                                                                            ~
2 errors generated.

I'm guessing that "cannot convert initializer list argument to 'std::tuple<std::__cxx11::basic_string<char>, unsigned long>'" is the important error here, the rest will go away if that did not occur. However I can't find any other configuration of { which will compile with my current compilers ...

[horenmar]

At a glance, this is likely the same problem as described in Generators.tests.cpp line 34 and below.

Also please avoid tabs (CMakeLists.txt for examples)

[richardash1981]

Thanks for the pointers. Hopefully this version will build on all targets ...

[codecov]

Codecov Report

Merging #1963 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #1963   +/-   ##
=======================================
  Coverage   88.59%   88.59%           
=======================================
  Files         138      138           
  Lines        5619     5619           
=======================================
  Hits         4978     4978           
  Misses        641      641           

[richardash1981]

Thank you for the merge!
Was the re-format done by an automated tool or manually? In other words is there something I should have done to the code before pushing, or a coding standard I should have followed? Ah, #1182. I need to learn about using clang-tidy ...

[horenmar]

Both. Clang-format was just introduced, and I am still experimenting with the settings, so I sometimes override it manually.

I also updated the contributing docs to mention clang-format.