README

Text diff library for PHP

Installation

composer require yusitnikov/php-diff

Usage

Create an instance of LevenshteinDiffCalculator. Arguments:

1. string $separatorRegex - separator RegEx that will split the strings into units. By default, strings will be split into letters.
2. OperationCostCalculator $operationCostCalculator - specify it to apply custom operation costs. By default, the cost for each operation (insert, delete, replace) will be 1.
3. StringDiffCalculatorInterface $itemDiffCalculator - diff calculator that would be applied when replacing a unit.

Example 1. Simple use-case - calculate distance and diff letter by letter.

use Chameleon\PhpDiff\LevenshteinDiffCalculator; $s1 = 'Levenshtein'; $s2 = 'Einstein'; $differ = new LevenshteinDiffCalculator(); var_dump($differ->calcDistance($s1, $s2)); var_dump($differ->calcDiff($s1, $s2));

Output:

int(5) class Chameleon\PhpDiff\StringDiffResult#14 (2) { public $distance => int(5) public $diff => array(5) { [0] => class Chameleon\PhpDiff\StringDiffOperation#12 (2) { public $operation => string(6) "DELETE" public $content => string(4) "Leve" } [1] => class Chameleon\PhpDiff\StringDiffOperation#13 (2) { public $operation => string(6) "INSERT" public $content => string(2) "Ei" } [2] => class Chameleon\PhpDiff\StringDiffOperation#7 (2) { public $operation => string(5) "MATCH" public $content => string(2) "ns" } [3] => class Chameleon\PhpDiff\StringDiffOperation#5 (2) { public $operation => string(6) "DELETE" public $content => string(1) "h" } [4] => class Chameleon\PhpDiff\StringDiffOperation#4 (2) { public $operation => string(5) "MATCH" public $content => string(4) "tein" } } } 

The corresponding diff:

- Leve + Ei ns - h tein

Example 2. Complex differ - compare lines and words

use Chameleon\PhpDiff\LevenshteinDiffCalculator; use Chameleon\PhpDiff\OperationCostCalculator; $s1 = 'And now here is my secret, a very simple secret: it is only with the heart that one can see rightly, what is essential is invisible to the eye.  "The Little Prince", Antoine de Saint-Exupéry'; $s2 = '> So here is my secret, > its only with heart that somebody can see rightly, > what is essential is always invisible to the eye. > I can promise it to you.  - Le Petit Prince, Antoine Marie Jean-Baptiste Roger, comte de Saint-Exupéry'; $lineDiffer = new LevenshteinDiffCalculator(LevenshteinDiffCalculator::SPLIT_WORDS_REGEX); $textDiffer = new LevenshteinDiffCalculator( LevenshteinDiffCalculator::SPLIT_LINES_REGEX, (new OperationCostCalculator())->setReplaceDistanceCalculator($lineDiffer), $lineDiffer ); $result = $textDiffer->calcDiff($s1, $s2);