Editing Unlambda (section)

==Basic principles==
As an [[esoteric programming language]], Unlambda is meant as a demonstration of very pure functional programming rather than for practical use. Its main feature is the lack of conventional operators and data types&mdash;the only kind of data in the program are one-parameter functions.  Data can nevertheless be simulated with appropriate functions as in the [[lambda calculus]].  Multi-parameter functions can be represented via the method of [[currying]].

Unlambda is based on the principle of [[abstraction elimination]], or the elimination of all saved variables, including functions. As a purely functional language, Unlambda's functions are [[first-class object]]s, and are the ''only'' such objects.

Here is an implementation of a [[hello world program]] in Unlambda:<ref name="chu2006"/>

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