Anonymous function #

We have seen in the dedicated section that a function can be written anonymously, as a lambda expression.

Anonymous functions are a traditional feature of functional languages (like Haskell). But they have also been integrated to a variety of imperative languages, for instance:

• Python (since 1994),
• Javascript (since its initial release in 1995),
• C# (since 2007)
• C++ (since 2011)
• Java (since 2014)
• Rust (since its initial release in 2015)

In Haskell #

Syntax. “$\lambda x.$” in Haskell is written \x ->

Example. The two following functions are equivalent:

aFunction :: Integer -> Integer
aFunction x = x + 2

theSameFunction :: Integer -> Integer
theSameFunction = \x -> x + 2