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Closure

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<hask>f</hask> returns a closure, because the variable <hask>x</hask>, which is bound outside of the [[lambda abstraction]] is used inside its definition.
 
<hask>f</hask> returns a closure, because the variable <hask>x</hask>, which is bound outside of the [[lambda abstraction]] is used inside its definition.
   
An interesting a side note: the context in which <hask>x</hask> was bound shouldn't even exist anymore, and wouldn't, had the lambda abstraction not closed around x.
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An interesting side note: the context in which <hask>x</hask> was bound shouldn't even exist anymore, and wouldn't, had the lambda abstraction not closed around x.
   
 
[[Category:Glossary]]
 
[[Category:Glossary]]

Latest revision as of 18:06, 29 September 2010

A closure, the opposite of a combinator, is a function that makes use of free variables in its definition. It 'closes' around some portion of its environment. for example

f x = (\y -> x + y)
f
returns a closure, because the variable
x
, which is bound outside of the lambda abstraction is used inside its definition. An interesting side note: the context in which
x
was bound shouldn't even exist anymore, and wouldn't, had the lambda abstraction not closed around x.