3 ms·

Functional doesn't really have a consistent definition, and you end up always with "yeah but"s in any discussion e.g. haskell isn't functional because C ffi and

Functional doesn't really have a consistent definition, and you end up always with "yeah but"s in any discussion e.g. haskell isn't functional because C ffi and unsafePerformIO. Point being, its very hard to say "X is or is not functional", as there isn't an objective consideration. (FYI, I love Haskell and use it daily and write it professionally)

ltbarcly3 5y ago
This language has mutable strings. This is in some sense the opposite of functional style.
- JoelMcCracken 5y ago
  So for me the primary qualifier is “are functions first class”; then “can functions be defined like data” (lambda); then “does it have a rich library of functionality that allows one to program functionally with it”; then “Is fp style idiomatic” ; then probably “does it have a good method to control mutability”; then “does it control side effects” There may be some other examples in there. Personally I like things with controlled side effects. But it’s just my preferred set of trade offs. Anyway I mean its just tough to be dogmatic about it. I get what you’re saying but why is that the dividing line?
  - ltbarcly3 5y ago
    Functional style does not allow for 'evolving' a value in multiple steps. In some sense this is the heart of the difference between functional style and other styles of programming. Language features which are only possibly used in a non-functional style make me want to say that describing the language as 'functional' is either wrong or saying a language is 'functional' is a meaningless claim. If every language is functional, saying it is completely redundant. I like your idea of saying FP style is idiomatic in that language might qualify the language as being described as 'functional', which I think agrees with my intuition that mutable strings being built in is evidence that calling that language 'Functional' is misleading or silly.

ltbarcly3 5y ago

This language has mutable strings. This is in some sense the opposite of functional style.

JoelMcCracken 5y ago
So for me the primary qualifier is “are functions first class”; then “can functions be defined like data” (lambda); then “does it have a rich library of functionality that allows one to program functionally with it”; then “Is fp style idiomatic” ; then probably “does it have a good method to control mutability”; then “does it control side effects” There may be some other examples in there. Personally I like things with controlled side effects. But it’s just my preferred set of trade offs. Anyway I mean its just tough to be dogmatic about it. I get what you’re saying but why is that the dividing line?
- ltbarcly3 5y ago
  Functional style does not allow for 'evolving' a value in multiple steps. In some sense this is the heart of the difference between functional style and other styles of programming. Language features which are only possibly used in a non-functional style make me want to say that describing the language as 'functional' is either wrong or saying a language is 'functional' is a meaningless claim. If every language is functional, saying it is completely redundant. I like your idea of saying FP style is idiomatic in that language might qualify the language as being described as 'functional', which I think agrees with my intuition that mutable strings being built in is evidence that calling that language 'Functional' is misleading or silly.