[cogman10]

> learning a Lisp also makes you a better coder

It can do, but it also can make you a worse coder. Specifically in typed languages.

One of the issues I've ran into with Clojure devs doing Java is that instead of relying on a type, they tend to want to write stuff like `Map<String, Map<String, Object>>`. Even when the key sets in both maps are well known.

This becomes worse when you mix that with Immutability. Immutability can be fine except when you need a mutation. In applications that require heavy mutation of data a `Map<String, Map<String, Object>>` is one of the worst ways to represent structured data, copying that structure is EXTREMELY expensive.

This isn't to say that you shouldn't usually strongly prefer Immutability. But it's also to say you shouldn't underestimate the cost of allocations and copying data.

Theres always tradeoffs. Part of being a good programmer is knowing when those tradeoffs are best applied.

[cutler]

Clojure data structures implement structural sharing which minimises copying overhead.

[KingMob]

True, but persistent data structures are still 2x-4x slower than mutable structures on average.