[crickey]

I dont undestand your example, plenty of languages add new keywords without breaking backwards compatibility, its removing a keyword that would cause such and issue.

[meepmorp]

I have named a function 'foo', in current version of language. A future change makes 'foo' a keyword. My code was broken by adding a keyword.

[earthboundkid]

This is not theoretical: Python broke a lot of async packages when they made “async” a keyword!

[crickey]

I guess, some languages get around this by having a destinction between functions and keyword functions not having the () braces in the syntax. But really if ur defning functions as keywords u should just put it in the standard library