Something like this is almost guaranteed to break stuff:
In PHP 5.5, you can ensure that output buffers are ended properly using a try-finally block. Assuming that your buffer is always the first buffer, or otherwise closing pre-existing buffers, could lead to problems. You should only end as many output buffers as you start. On most web servers I've used, output buffering is already one level deep before my scripts start running. You can use ob_get_level() to determine if an output buffer has already been started. Keep in mind that output may be buffered by default, depending on how you are running PHP (CGI, CLI, etc.).
#Cleanx function php archive
Imagine a templating or input validation library, where a closure isĭefined to capture variables in scope and access them later when the anonymous function is evaluated.Getting Started Introduction A simple tutorial Language Reference Basic syntax Types Variables Constants Expressions Operators Control Structures Functions Classes and Objects Namespaces Enumerations Errors Exceptions Fibers Generators Attributes References Explained Predefined Variables Predefined Exceptions Predefined Interfaces and Classes Context options and parameters Supported Protocols and Wrappers Security Introduction General considerations Installed as CGI binary Installed as an Apache module Session Security Filesystem Security Database Security Error Reporting User Submitted Data Hiding PHP Keeping Current Features HTTP authentication with PHP Cookies Sessions Dealing with XForms Handling file uploads Using remote files Connection handling Persistent Database Connections Command line usage Garbage Collection DTrace Dynamic Tracing Function Reference Affecting PHP's Behaviour Audio Formats Manipulation Authentication Services Command Line Specific Extensions Compression and Archive Extensions Cryptography Extensions Database Extensions Date and Time Related Extensions File System Related Extensions Human Language and Character Encoding Support Image Processing and Generation Mail Related Extensions Mathematical Extensions Non-Text MIME Output Process Control Extensions Other Basic Extensions Other Services Search Engine Extensions Server Specific Extensions Session Extensions Text Processing Variable and Type Related Extensions Web Services Windows Only Extensions XML Manipulation GUI Extensions Keyboard Shortcuts ? This help j Next menu item k Previous menu item g p Previous man page g n Next man page G Scroll to bottom g g Scroll to top g h Goto homepage g s Goto search For true closures with lateīinding one should use a reference when importing. The single filter returned byĬriteria_greater_than is a closure with $min argument closed by the value in the scope (given as an argument whenĮarly binding is used by default for importing $min variable into the created function. */ function criteria_greater_than ( $min ) $input = array ( 1, 2, 3, 4, 5, 6 ) // Use array_filter on a input with a selected filter function $output = array_filter ( $input, criteria_greater_than ( 3 )) print_r ( $output ) // items > 3Įach filter function in the family accepts only elements greater than some minimum value. * Returns a single filter out of a family of "greater than n" filters The built-in array_filter()įunction asks both for the input array (data) and a function (a strategy or a callback) used as a filter function on
The most common usage of higher-order functions is when implementing a strategy pattern. PHP 5.4 added the ability to bind closures to an object’s scope and also improved support for callables such that theyĬan be used interchangeably with anonymous functions in almost all cases. Recursion, a feature that allows a function to call itself, is supported by the language, but most of the PHP codeĪnonymous functions (with support for closures) have been present since PHP 5.3 (2009). A Clean function is referential transparent: the result of a function only depends on the value of the. This has a big advantage: a function cannot have a side-effect. Clean is a pure functional language, there is not such a thing as an assignment.
Other functions and a function can return other functions (a feature called higher-order functions). A Functional Programming Language like Clean is based on the concept of mathematical functions. Both user-defined andīuilt-in functions can be referenced by a variable and invoked dynamically. PHP supports first-class functions, meaning that a function can be assigned to a variable.
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