impure

You can't get this guarantee in impure languages.

This impure code is responsible for say, reading a string from the user input.

But to do so, you have to acknowledge certain, impure realities about Free software in the real world.

This is only a valid argument about lazy, impure languages, and I don't think any exist.

" There's another point of view that they're entirely impure: "I'm manipulating state in this function, so of course it's impure!

?Without going into too much detail, there are ways in Haskell to isolate impurity to a small part of the code which is clearly marked as impure.

Thus, these languages provide a more direct route to controlling low level aspects and can use object-oriented and impure language features.

The above is actually impure because it implements `fibs` as a function when really the Fibonacci numbers are a sequence and should be treated that way.

[invocation of Clarke's 3rd law excised for triteness]The same could be said about Haskell itself: "Of course it's impure, because there's a call stack being destructively modified as it runs!

Has there been any exploration into an idea where the problem with side effects is not that they make functions impure, but they are often against the metaphor of the instructions being given?

If we look at an impure language like JavaScript through Haskell-colored glasses, essentially every line of code in a JS program is automatically in the IO monad.

As elegant and appealing as Haskell's purely functional foundation is, it prohibits simple, but crucial, impure tasks such as writing to files and communicating over networks.

Some altered states of consciousness achievable through the use of these substances are considered to be "impure" or "derranged" in some way, and their users are considered immoral, depraved or wicked.

Fortunatly, repeatedly saying the same things "Scheme shares Haskell's unsuitability for production code" "it prohibits simple, but crucial, impure tasks such as writing to files and communicating over networks" "it is beautiful, but it is useless for hacking" doesn't make them true.