The problem with "stream/generator as default" is the boilerplate you constantly have to add.
In Python 3, for example, map() returns a generator. So you can no longer transform a list into another list with `new = map(func, lst)`. You have to do `new = list(map(func, lst))`. One of the most subtle gotchas when upgrading from 2 to 3 is having to wrap list() around functions and methods like map(), range(), dict.items(), etc.
Discussion I've seen about Rust on less moderated websites often seems to make fun of the .unwrap() spam seen in a lot of programs, to the point of the mockery even dominating some discussions.
Streams and lazy evaluation are really nice, but sometimes you just want some nice procedural handling.
When using Rust for more than toy programs (which, assuming I am thinking of the same "less moderated" websites that you are, is unlikely to be the experience of the commenters), unwrap() isn't particularly common outside of main(). You generally want to handle the error cases. It's used a lot in examples because they have to function as one-offs.
As another comment mentioned, .unwrap() is really useful for testing things out, but any legitimate (read: with intent to be used for some practical purpose) library or program is going to handle most errors. One edge case may be calling unwrap() in a thread that should die if the unwrapped operation doesn't succeed.
In Python 3, for example, map() returns a generator. So you can no longer transform a list into another list with `new = map(func, lst)`. You have to do `new = list(map(func, lst))`. One of the most subtle gotchas when upgrading from 2 to 3 is having to wrap list() around functions and methods like map(), range(), dict.items(), etc.
Discussion I've seen about Rust on less moderated websites often seems to make fun of the .unwrap() spam seen in a lot of programs, to the point of the mockery even dominating some discussions.
Streams and lazy evaluation are really nice, but sometimes you just want some nice procedural handling.