Matrix structure

Standard matrix workflow structure is as below, with access as matrix.os & matrix.ruby:

matrix:
  os: [ ubuntu-16.04, ubuntu-18.04, macos-latest, windows-latest ]
  ruby: [ 2.2, 2.3, .ruby-version, .tool-versions, head, jruby, jruby-head, truffleruby ]

But the following also works, with access as matrix.cfg.os & matrix.cfg.ruby:

matrix:
  cfg:
    - { ruby: rubinius, os: ubuntu-18.04   }
    - { ruby: mingw   , os: windows-latest }
    - { ruby: mswin   , os: windows-latest }

The 2nd type can be very helpful when the matrix is sparse.

Questions:

1. Is the second type supported?

2. If above is true, the different access syntax is messy if one changes from one to the other. If the following was supported, the access would be identical. The distinction between the first ‘standard’ matrix and the one below is simply whether the first array element is another array or an object/hash…

matrix:
  - { ruby: rubinius, os: ubuntu-18.04   }
  - { ruby: mingw   , os: windows-latest }
  - { ruby: mswin   , os: windows-latest }

[ericsciple]

lol - i got sidetracked, other stuff came up. The work is done i just need to push on reviewers.

If you want, feel free to leave open and I can communicate an ETA here.

[eregon]

This works nicely, thanks!