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map, filter, etc are not 'functional'. 'functional' doesn't mean 'functions'. It is all about side effects, and that the procedures in the language are like m

map, filter, etc are not 'functional'. 'functional' doesn't mean 'functions'. It is all about side effects, and that the procedures in the language are like mathematical functions: without state or side effects. Using your definition, virtually every language in use today is 'functional', all the way down to Fortran 77, since really any language you can get a pointer or other handle to a function or callable object would let you implement map, filter, etc. Really the existence of map, filter, etc are not a clue to a language being 'functional'. Yes, you would need such things, but they are not sufficient. C is not a 'functional language', even though technically you can write C that is completely functional in style. In fact, almost any modern language can be used in a 100% functional style, avoiding side effects and state completely. Nobody does this. Even if it is one of your favorite things, virtually no one uses functional languages. This isn't because people are dumb, it's because functional languages are cumbersome and inefficient.

lispm 10y ago
I would not think passing procedure pointers in C makes it able to support functional programming. That's very shallow. C lacks (last I looked) nested functions, closures, functions as first class data types, ... > Really the existence of map, filter, etc are not a clue to a language being 'functional'. 'Functional Programming' isn't black and white. There are pure languages which ENFORCE functional programming like Haskell. It's their many paradigm, the language and its library make heavy use of FP and one has to actively manage side-effects. Then there are language which SUPPORT some forms of functional programming, for example by providing a subset in the language and its libraries which can be used side-effect free, makes use of higher-order functions, etc. At the bottom are languages which ENABLE some basic functional programming idioms. Though most of the language and its libraries are not using FP, the user can still use some FP constructs like nested functions, closures, etc. Generally I agree, that pure FP is not that much used in the real world because of a lot actual problems (difficult to learn/use/maintain, efficiency might be achievable by experts, needs understanding of slightly advanced mathematical concepts, ...). There are some more or less used implementation languages of more or less pure FP (GHC, OCAML, F#, ..., Clojure) languages. I'd guess that the main applications are in domains where they have highly skilled people: finance, data analytics, verification/specification, ... I sometimes see that companies advertise use of FP languages, but in reality that's marketing in recruiting to look cool and to attract clever people (who then have to work on Java jobs, mostly).
qwertyuiop924 10y ago
I wasn't making the point that map and filter were functional, I was trying to say that those were concepts originating in FP. And that they appear in so many languages demonstrates some of FP's influence.

lispm 10y ago

I would not think passing procedure pointers in C makes it able to support functional programming. That's very shallow. C lacks (last I looked) nested functions, closures, functions as first class data types, ... > Really the existence of map, filter, etc are not a clue to a language being 'functional'. 'Functional Programming' isn't black and white. There are pure languages which ENFORCE functional programming like Haskell. It's their many paradigm, the language and its library make heavy use of FP and one has to actively manage side-effects. Then there are language which SUPPORT some forms of functional programming, for example by providing a subset in the language and its libraries which can be used side-effect free, makes use of higher-order functions, etc. At the bottom are languages which ENABLE some basic functional programming idioms. Though most of the language and its libraries are not using FP, the user can still use some FP constructs like nested functions, closures, etc. Generally I agree, that pure FP is not that much used in the real world because of a lot actual problems (difficult to learn/use/maintain, efficiency might be achievable by experts, needs understanding of slightly advanced mathematical concepts, ...). There are some more or less used implementation languages of more or less pure FP (GHC, OCAML, F#, ..., Clojure) languages. I'd guess that the main applications are in domains where they have highly skilled people: finance, data analytics, verification/specification, ... I sometimes see that companies advertise use of FP languages, but in reality that's marketing in recruiting to look cool and to attract clever people (who then have to work on Java jobs, mostly).

qwertyuiop924 10y ago

I wasn't making the point that map and filter were functional, I was trying to say that those were concepts originating in FP. And that they appear in so many languages demonstrates some of FP's influence.