Big changes to Erlang
I love this:"Key := Val Updates an existing Key
The key must be present in the old map. If Key is not in the old map Erlang will complain loudly.
Using two operations instead of one has several advantages:
A spelling mistake cannot accidentally introduce a new key"Lord knows how many times I accidentally created a new key with a spelling typo, and then later when I wanted to retrieve the data, I was like "What the hell is wrong? I know I put data in that key, so why is nothing coming back? I guess I have discovered a rare bug in the compiler that no one has ever discovered before."