PHP code example of dbeurive / lexer

    
        
<?php
require_once('vendor/autoload.php');

/* Start to develop here. Best regards https://php-download.com/ */

    

dbeurive / lexer example snippets

    $varProcessor = function(array $inMatches) {
        $name = strtolower($inMatches[2]);
        switch (strtoupper($inMatches[1])) {
            case 'L': return 'LOCAL_'  . $name;
            case 'G': return 'GLOBAL_' . $name;
        }
        throw new \Exception("Impossible error!");
    };
   
    $tokens = array(
        array('/[0-9]+/',                'numeric'),
        array('/\\$([lg])([a-z0-9]+)/i', 'variable', $varProcessor),
        array('/[a-z]{2,}/i',            'function'),
        array('/(\\+|\\-|\\*|\\/)/',     'operator'),
        array('/\\(/',                   'open_bracket'),
        array('/\\)/',                   'close_bracket'),
        array('/(\\s+|\\r?\\n)/',        'blank', function(array $m) { return null; })
    );
    
    try {
        $lexer = new Lexer($tokens);
        $text = '$gConstant1 + sin($lCoef1) / cos($lcoef2) * $gTemp - tan(21)';
        $tokens = $lexer->lex($_text);
    } catch (\Exception $e) {
        print "ERROR: " . $e->getMessage() . "\n";
        exit(1);
    }
    
    /** @var Token $_token */
    foreach ($tokens as $_token) {
        printf("%s %s\n", $_token->type, $_token->value);
    }

    use dbeurive\Lexer\Lexer;
    use dbeurive\Lexer\Token;
    
    $text = 'AAAA AA';
    
    // ---------------------------------------------------------
    // TEST 1
    // ---------------------------------------------------------
    
    $specifications = array(
        array('/AA/',                    'type A2'),
        array('/A/',                     'type A1'),
        array('/(\\s+|\\r?\\n)/',        'blank', function(array $m) { return null; })
    );
    
    try {
        $lexer = new Lexer($specifications);
        $tokens = $lexer->lex($text);
    } catch (\Exception $e) {
        print "ERROR: " . $e->getMessage() . "\n";
        exit(1);
    }
    
    print "Test1: $text\n\n";
    dumpToken($tokens);
    print "\n";
    
    // ---------------------------------------------------------
    // TEST 2
    // ---------------------------------------------------------
    
    $specifications = array(
        array('/A/',                     'type A1'),
        array('/AA/',                    'type A2'),
        array('/(\\s+|\\r?\\n)/',        'blank', function(array $m) { return null; })
    );
    
    try {
        $lexer = new Lexer($specifications);
        $tokens = $lexer->lex($text);
    } catch (\Exception $e) {
        print "ERROR: " . $e->getMessage() . "\n";
        exit(1);
    }
    
    print "Test2: $text\n\n";
    dumpToken($tokens);
    
    exit(0);
    
    function dumpToken(array $inTokens) {
        $max = 0;
    
        /** @var Token $_token */
        foreach ($inTokens as $_token) {
            $max = strlen($_token->type) > $max ? strlen($_token->type) : $max;
        }
    
        /** @var Token $_token */
        foreach ($inTokens as $_token) {
            printf("%${max}s %s\n", $_token->type, $_token->value);
        }
    }

    /**
     * Lexer constructor.
     * @param array $inSpecifications This array represents the tokens specifications.
     *        Each element of this array is an array that specifies a token.
     *        It contains 2 or 3 elements.
     *        - First element: a regular expression that describes the token.
     *        - Second element: the name of the token.
     *        - Third element: an optional callback function.
     *          The signature of this function must be:
     *          null|string function(array $inMatches)
     * @throws \Exception
     */
    public function __construct(array $inSpecifications)

    /**
     * Explode a given string into a list of tokens.
     * @param string $inString The string to explode into tokens.
     * @return array The method returns a list of tokens.
     *         Each element of the returned list is an instance of the class Token.
     * @throws \Exception
     * @see Token
     */
    public function lex($inString) 

    /**
     * Class Token
     *
     * This class implements a token.
     *
     * @package dbeurive\Lexer
    */
    class Token
    {
        /** @var null|mixed Token's value. */
        public $value = null;
        /** @var null|string Token's type. */
        public $type = null;
    
        /**
         * Token constructor.
         * @param string $inOptValue The token's value.
         * @param string $inOptType The token's type.
         */
        public function __construct($inOptValue=null, $inOptType=null)
        {
            $this->value = $inOptValue;
            $this->type  = $inOptType;
        }
    }