---
impl:
    gcc48:
        executable: gcc
        version: "%(executable)s --version"
        build: "%(executable)s -O2 %(CFLAGS)s %(LDFLAGS)s %(source)s -o %(output)s"
        run: "%(output)s"
        impl: c

    g++48:
        executable: g++
        version: "%(executable)s --version"
        build: "%(executable)s -O2 %(CFLAGS)s %(LDFLAGS)s %(source)s -o %(output)s"
        run: "%(output)s"
        impl: c++

    clang:
        executable: clang
        version: "%(executable)s --version"
        build: "%(executable)s -O2 %(CFLAGS)s %(LDFLAGS)s %(source)s -o %(output)s"
        run: "%(output)s"
        impl: c

    clang++:
        executable: clang++
        version: "%(executable)s --version"
        build: "%(executable)s -O2 %(CFLAGS)s %(LDFLAGS)s %(source)s -o %(output)s"
        run: "%(output)s"
        impl: c++

game:
    nbody:
        nicename: n-body
        description: Simulate motion of outer planets for N steps.
        levels:
            - args: 500000
            - args: 5000000
            - args: 50000000

---
impl:
  gcc48:
    executable: gcc
    version: "%(executable)s --version"
    build: "%(executable)s -O2 %(CFLAGS)s %(LDFLAGS)s %(source)s -o %(output)s"
    run: "%(output)s"
    impl: c

  g++48:
    executable: g++
    version: "%(executable)s --version"
    build: "%(executable)s -O2 %(CFLAGS)s %(LDFLAGS)s %(source)s -o %(output)s"
    run: "%(output)s"
    impl: c++

  clang:
    executable: clang
    version: "%(executable)s --version"
    build: "%(executable)s -O2 %(CFLAGS)s %(LDFLAGS)s %(source)s -o %(output)s"
    run: "%(output)s"
    impl: c

  clang++:
    executable: clang++
    version: "%(executable)s --version"
    build: "%(executable)s -O2 %(CFLAGS)s %(LDFLAGS)s %(source)s -o %(output)s"
    run: "%(output)s"
    impl: c++

game:
  nbody:
    nicename: n-body
    description: Simulate motion of outer planets for N steps.
    levels:
      - args: 500000
      - args: 5000000
      - args: 50000000

Reduce indent to two spaces
Reduce indent to two spaces
