This was making my eyes bleed as I read over code.
I used the following in vim. I made them up on the fly, but they seemed
to pass manual inspection.
:g/},\n\s*{$/s//}, {/
:w
:g/{$\n\s*{$/s//{{/
:w
:g/^\(\s*\)},\n\1},$/s//}},/
:w
:g/^\(\s*\)},$\n\1}$/s//}}/
:w