dana-ross

<?php

class Just {
  
  protected $value;
  
  function __construct( $value ) {
    $this->value = $value;  
  }
  

dana-ross

/**
 * Wrapper to deal with global state and pass it to a pure function
 * IMPURE - references global $post
 * @return string
 */
function capitalize_the_post_title() {
  global $post;
  return _capitalize_the_post_title( $post );
  // Or return _capitalize_the_post_title( $GLOBALS['post'] );
}

dana-ross

/**
 * Convert a value to non-negative integer.
 *
 * @since 2.5.0
 *
 * @param mixed $maybeint Data you wish to have converted to a non-negative integer.
 * @return int A non-negative integer.
 */
$absint = compose( 'abs', 'intval' );

dana-ross

$add_the_content_filter = partially_apply( 'add_filter', 'the_content' );

function reverse_the_content( $content ) {
  return strrev( $content );
}

$add_the_content_filter( 'reverse_the_content' );

dana-ross

function render_subhead_meta_box() {
  echo 'This is my meta box';
}

// This is equivalent to:
// add_meta_box( 'subhead', 'Article Subhead', 'render_subhead_meta_box' )
$add_meta_box_subhead = curry( 'add_meta_box', 'subhead' );
$add_meta_box_subhead_with_title = $add_meta_box_subhead( 'Article Subhead' );
$add_meta_box_subhead_with_title( 'render_subhead_meta_box' );

dana-ross

function busy_work( $value ) {
  $sha256 = partially_apply( 'hash', 'sha256' );
  $retval = $value;
  for( $i = 0; $i < 1000; $i++ ) {
    $retval = $sha256( $retval );
  }
  
  return $retval;
}

dana-ross

<?php

/*
Plugin Name: Comment Hash
Description: Sign comments with a sha256 hash to prevent tampering
Author: Dave Ross
Version: 1.0
Author URI: http://davidmichaelross.com/
*/

dana-ross

<?php

/**
 * Return the object's value + 2
 */
function f( $obj ) {
	$retval = $obj->value + 2;
	$obj->value = 5; // EVIL!
	return $retval;
}

dana-ross

<?php

use DaveRoss\FunctionalProgrammingUtils\Just as Just;

$f = function( $value ) {
        $retval = $value + 2;
        $value = 5; // Who cares?
        return $retval;
};

dana-ross

<?php

$good = json_decode('{ "label": "This is valid JSON", "value": 5 }' );
$bad  = json_decode('{ "label": This is invalid JSON, "value": 5 }' );

if( is_null( $good ) ) {
        echo "Couldn't parse good JSON\n";
}
else {
        echo $good->value . "\n";