Computation proceeds by nested or composed function calls, without changes to state or mutable data. In functional programming, a program consists entirely of evaluation of pure functions. What Is Functional Programming?Ī pure function is a function whose output value follows solely from its input values, without any observable side effects. Under unix, you can use the #! convention to make a script executable.Free Bonus: 5 Thoughts On Python Mastery, a free course for Python developers that shows you the roadmap and the mindset you’ll need to take your Python skills to the next level.

Transformed in all sorts of ways, using functions.

Lists and finite maps, which operate much like arrays and hashes of theĪ list is just an ordered, um, list of values. Haskell has many many collection types, but in particular, it has

Often you need to collect a bunch of values together into some kind ofĬollection. Mutable boxes, and they're available as a library for when you need that). (Of course, some problems need (threadsafe) Interesting optimisations, and makes understanding what a program is doing atĪny point much easier, since you don't have to worry about what state a Having such a simple system for variables allows for a wide range of Main = print more => main = print ( another + answer ) => main = print (( answer + 1 ) + answer ) => main = print (( answer + 1 ) + 42 ) => main = print (( 42 + 1 ) + 42 ) => main = print ( 43 + 42 ) => main = print 85 => 85 Indicates which library modules are in scope, and in this case, only the basic The interpreter now waits for your code fragments. Now, from your package system, or the GHC home page. (or its interactive front end, GHCi, for all code. Provides both an optimising native code compiler, and an interactive Most widely used implementation of Haskell currently is GHC, which Like some languages Haskell can be both compiled and interpreted.

Haskell functional programming tutorial