Anonymous Functions in PHP 5.3

72 Pages·2011·0.11 MB·English

Anonymous Functions in PHP 5.3
Matthew Weier O’Phinney
26 April 2011
But first, some vocabulary
Lambdas
•
From “lambda calculus”
26 April 2011 Anonymous Functions in PHP 5.3 3
Lambdas
•
From “lambda calculus”
•
Names of functions are merely a “convenience”, and
hence all functions are considered anonymous
26 April 2011 Anonymous Functions in PHP 5.3 3
Lambdas
•
From “lambda calculus”
•
Names of functions are merely a “convenience”, and
hence all functions are considered anonymous
•
Unless you’re using a true functional programming
language with first-class functions, most likely you’re
simply using anonymous functions, or lambda
expressions.
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Closures
•
A function which includes a referencing environment
26 April 2011 Anonymous Functions in PHP 5.3 4
Closures
•
A function which includes a referencing environment
•
Each function has its own scope
•
Allows hiding state
26 April 2011 Anonymous Functions in PHP 5.3 4
Closures
•
A function which includes a referencing environment
•
Each function has its own scope
•
Allows hiding state
•
Differentiating factor is that closures allow binding
references that exist at the time of creation, to use
when called.
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Anonymous Functions
•
Any function defined and/or called without being
bound to an identifier.
•
You can assign the function to a variable, but
you’re not giving it its own name.
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