Pelzini

source of /processor/analyser.php

Contains the Analyser class

<?php
/*
Copyright 2008 Josh Heidenreich
 
This file is part of Pelzini.
 
Pelzini is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
 
Pelzini is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with Pelzini.  If not, see <http://www.gnu.org/licenses/>.
*/
 
 
/**
 * Contains the {@link Analyser} class
 *
 * @package Parsers
 * @author Josh
 * @since 0.2
 **/
 
/**
 * Generic language analyser. Analysers are used to tranform the language-specific tokens into a set of {@link CodeParserItem ParserItems}
 **/
abstract class Analyser
{
    private $tokens;
    private $pos;
    private $token_pos;
 
    /**
     * Resets the analyser ready for more parsing work
     **/
    public function resetState()
    {
        $this->tokens = array();
        $this->pos = 0;
        $this->token_pos = 0;
    }
 
 
    /**
     * Processes a set of token and populates a {@link ParserFile}
     **/
    abstract public function process($tokens, $parser_file);
 
 
    /**
     * Tells the analyser what tokens it should use
     **/
    final protected function setTokens($tokens)
    {
        $this->tokens = $tokens;
    }
 
 
    /**
     * Sets the current position
     **/
    final protected function setPos($pos)
    {
        $this->pos = $pos;
    }
 
 
    /**
     * Moves the internal token pointer forwards
     *
     * @param $num integer The number of positions to move the pointer forwards
     **/
    final protected function movePosForward($num = 1)
    {
        $this->pos += $num;
    }
 
 
    /**
     * Moves the internal token pointer backwards
     *
     * @param $num integer The number of positions to move the pointer backwards
     **/
    final protected function movePosBackward($num = 1)
    {
        $this->pos -= $num;
    }
 
 
    /**
     * Returns a token at a specific position
     * If no position is specified, uses the current position
     **/
    final protected function getToken($pos = null)
    {
        if ($pos === null) $pos = $this->pos;
        return $this->tokens[$pos];
    }
 
 
    /**
     * Returns the current position
     **/
    final protected function getPos()
    {
        return $this->pos;
    }
 
 
    /**
     * Finds a token looking forward from the current position.
     * Searching starts after the current token.
     * The token must be of the type specified
     *
     * @param mixed $token_types A token type constant, or an array of token type constants
     * @param mixed $stop_list Token(s) that should stop the search process
     * @return Token The found token, or null if nothing was found
     **/
    final protected function findTokenForwards($token_types, $stop_list = null)
    {
        if (! is_array($token_types)) $token_types = array($token_types);
        if (! is_array($stop_list)) $stop_list = array($stop_list);
 
        $pos = $this->pos;
        if ($pos != 0) $pos++;
 
        while (true) {
            if (empty($this->tokens[$pos])) break;
 
            $tok = $this->tokens[$pos];
            if (in_array($tok->getType(), $stop_list)) {
                break;
            }
 
            if (in_array($tok->getType(), $token_types)) {
                $this->token_pos = $pos;
                return $tok;
            }
 
            ++$pos;
        }
 
        return null;
    }
 
 
    /**
     * Finds a token looking backwards from the current position.
     * Searching starts before the current token.
     * The token must be of the type specified
     *
     * @param mixed $token_types A token type constant, or an array of token type constants
     * @param mixed $stop_list Token(s) that should stop the search process
     * @return Token The found token, or null if nothing was found
     **/
    final protected function findTokenBackwards($token_types, $stop_list = null)
    {
        if (! is_array($token_types)) $token_types = array($token_types);
        if (! is_array($stop_list)) $stop_list = array($stop_list);
 
        $pos = $this->pos - 1;
        while (true) {
            if (empty($this->tokens[$pos])) break;
 
            $tok = $this->tokens[$pos];
            if (in_array($tok->getType(), $stop_list)) {
                break;
            }
 
            if (in_array($tok->getType(), $token_types)) {
                $this->token_pos = $pos;
                return $tok;
            }
 
            --$pos;
        }
 
        return null;
    }
 
 
    /**
     * Gets the position of the last token found using one of the search functions
     **/
    final protected function getTokenPos()
    {
        return $this->token_pos;
    }
 
 
}
 
 
?>