language: cpp

addons:
  apt:
    sources:
      - llvm-toolchain-trusty-5.0
    packages:
      - clang-format-5.0 # needed for formatting

env:
  global:
    - CLANG_FORMAT_SUFFIX="-5.0"

matrix:
  include:
    - os: linux
      env: MATRIX_EVAL="CC=gcc-5 && CXX=g++-5"
      addons:
        apt:
          sources:
            - ubuntu-toolchain-r-test
          packages:
            - g++-5
    - os: linux
      env: MATRIX_EVAL="CC=clang-4.0 && CXX=clang++-4.0"
      addons:
        apt:
          sources:
            - llvm-toolchain-trusty-4.0
          packages:
            - clang-4.0 # note this is *NOT* the same version as clang-format
    - os: linux
      env: MATRIX_EVAL="CC=clang-5.0 && CXX=clang++-5.0"
      addons:
        apt:
          sources:
            - llvm-toolchain-trusty-5.0
          packages:
            - clang-5.0
    - os: osx
      osx_image: xcode9

# prevent Travis from overwriting our CXX variables
before_install:
    - eval "${MATRIX_EVAL}"
    - echo $CXX

script:
    - mkdir build
    - cd build
    - cmake -DCLANG_FORMAT_SUFFIX=$CLANG_FORMAT_SUFFIX --config Release ..
    - cmake --build . -- -j2