You know I never quite got that comma thing. For instance in python, the only reason it is necessary is because {"foo": "bar" "baz", 'k2':'v2'} is the same as {'foo':'barbaz', 'k2':'v2'}. Getting rid of auto-concatination allows for {'foo':'barbaz' 'k2':'v2'} which is pretty easy to parse base on tokens and ':'. It also eliminates a pretty common bug, in which there is kv pair per line, and the line ends with ',', except for the last line which does not have the ','. (The following line has a '}'). The common bug being adding a new kv pair and missing the ','.