Editing Unlambda (section)

{{Refimprove|date=August 2020}}
{{short description|Functional programming language}}
{{Infobox programming language
| name = Unlambda
| logo = <!-- (filename only) -->
| logo caption = 
| screenshot = <!-- (filename only) -->
| screenshot caption = 
| paradigm = Nearly [[Purely functional programming|pure]] [[Functional programming|functional]]
| family =  
| designer = David Madore
| developer = David Madore
| released = {{Start date and age|1999|06|28|df=yes}}
| latest release version = 2.0.0
| latest release date = {{Start date and age|1999|12|20|df=yes}}
| latest preview version = 
| latest preview date = <!-- {{Start date and age|YYYY|MM|DD|df=yes}} -->
| typing = [[Type system|Untyped]]
| scope = 
| programming language = [[Scheme (programming language)|Scheme]], [[C (programming language)|C]], [[Java (programming language)|Java]]
| discontinued =
| platform = 
| operating system = 
| license = [[GNU General Public License|GPL]] 2.0 or later
| file ext = 
| file format = <!-- or: | file formats = -->
| website = {{URL|www.madore.org/~david/programs/unlambda}}
| implementations = 
| dialects = 
| influenced by = 
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}}
'''Unlambda''' is a minimal, "nearly [[Purely functional language|pure]]"<ref name="chu2006">{{cite web|work=Good Math, Bad Math (blog)|first=Mark C.|last=Chu-Carroll|date=2006-08-11|title=Friday Pathological Programming: Unlambda, or Programming Without Variables|url=http://scienceblogs.com/goodmath/2006/08/11/friday-pathological-programmin-3/|publisher=ScienceBlogs}}</ref> [[functional programming language]] invented by David Madore. It is based on [[combinatory logic]], an expression system without the [[Lambda calculus|lambda operator]] or free variables. It relies mainly on two built-in functions (<code>s</code> and <code>k</code>) and an apply operator (written <code>`</code>, the [[backquote]] character). These alone make it [[Turing-complete]], but there are also some [[input/output]] (I/O) functions to enable interacting with the user, some shortcut functions, and a [[lazy evaluation]] function. Variables are unsupported.

Unlambda is [[free and open-source software]] distributed under a [[GNU General Public License]] (GPL) 2.0 or later.{{clarify|date=March 2022}}