<?php
/*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* This software consists of voluntary contributions made by many individuals
* and is licensed under the MIT license. For more information, see
* <http://www.doctrine-project.org>.
*/
namespace Doctrine\Common\Lexer;
/**
* Base class for writing simple lexers, i.e. for creating small DSLs.
*
* @since 2.0
* @author Guilherme Blanco <[email protected]>
* @author Jonathan Wage <[email protected]>
* @author Roman Borschel <[email protected]>
*/
abstract class AbstractLexer
{
/**
* Lexer original input string.
*
* @var string
*/
private $input;
/**
* Array of scanned tokens.
*
* Each token is an associative array containing three items:
* - 'value' : the string value of the token in the input string
* - 'type' : the type of the token (identifier, numeric, string, input
* parameter, none)
* - 'position' : the position of the token in the input string
*
* @var array
*/
private $tokens = array();
/**
* Current lexer position in input string.
*
* @var integer
*/
private $position = 0;
/**
* Current peek of current lexer position.
*
* @var integer
*/
private $peek = 0;
/**
* The next token in the input.
*
* @var array
*/
public $lookahead;
/**
* The last matched/seen token.
*
* @var array
*/
public $token;
/**
* Sets the input data to be tokenized.
*
* The Lexer is immediately reset and the new input tokenized.
* Any unprocessed tokens from any previous input are lost.
*
* @param string $input The input to be tokenized.
*
* @return void
*/
public function setInput($input)
{
$this->input = $input;
$this->tokens = array();
$this->reset();
$this->scan($input);
}
/**
* Resets the lexer.
*
* @return void
*/
public function reset()
{
$this->lookahead = null;
$this->token = null;
$this->peek = 0;
$this->position = 0;
}
/**
* Resets the peek pointer to 0.
*
* @return void
*/
public function resetPeek()
{
$this->peek = 0;
}
/**
* Resets the lexer position on the input to the given position.
*
* @param integer $position Position to place the lexical scanner.
*
* @return void
*/
public function resetPosition($position = 0)
{
$this->position = $position;
}
/**
* Retrieve the original lexer's input until a given position.
*
* @param integer $position
*
* @return string
*/
public function getInputUntilPosition($position)
{
return substr($this->input, 0, $position);
}
/**
* Checks whether a given token matches the current lookahead.
*
* @param integer|string $token
*
* @return boolean
*/
public function isNextToken($token)
{
return null !== $this->lookahead && $this->lookahead['type'] === $token;
}
/**
* Checks whether any of the given tokens matches the current lookahead.
*
* @param array $tokens
*
* @return boolean
*/
public function isNextTokenAny(array $tokens)
{
return null !== $this->lookahead && in_array($this->lookahead['type'], $tokens, true);
}
/**
* Moves to the next token in the input string.
*
* @return boolean
*/
public function moveNext()
{
$this->peek = 0;
$this->token = $this->lookahead;
$this->lookahead = (isset($this->tokens[$this->position]))
? $this->tokens[$this->position++] : null;
return $this->lookahead !== null;
}
/**
* Tells the lexer to skip input tokens until it sees a token with the given value.
*
* @param string $type The token type to skip until.
*
* @return void
*/
public function skipUntil($type)
{
while ($this->lookahead !== null && $this->lookahead['type'] !== $type) {
$this->moveNext();
}
}
/**
* Checks if given value is identical to the given token.
*
* @param mixed $value
* @param integer $token
*
* @return boolean
*/
public function isA($value, $token)
{
return $this->getType($value) === $token;
}
/**
* Moves the lookahead token forward.
*
* @return array|null The next token or NULL if there are no more tokens ahead.
*/
public function peek()
{
if (isset($this->tokens[$this->position + $this->peek])) {
return $this->tokens[$this->position + $this->peek++];
} else {
return null;
}
}
/**
* Peeks at the next token, returns it and immediately resets the peek.
*
* @return array|null The next token or NULL if there are no more tokens ahead.
*/
public function glimpse()
{
$peek = $this->peek();
$this->peek = 0;
return $peek;
}
/**
* Scans the input string for tokens.
*
* @param string $input A query string.
*
* @return void
*/
protected function scan($input)
{
static $regex;
if ( ! isset($regex)) {
$regex = sprintf(
'/(%s)|%s/%s',
implode(')|(', $this->getCatchablePatterns()),
implode('|', $this->getNonCatchablePatterns()),
$this->getModifiers()
);
}
$flags = PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE | PREG_SPLIT_OFFSET_CAPTURE;
$matches = preg_split($regex, $input, -1, $flags);
foreach ($matches as $match) {
// Must remain before 'value' assignment since it can change content
$type = $this->getType($match[0]);
$this->tokens[] = array(
'value' => $match[0],
'type' => $type,
'position' => $match[1],
);
}
}
/**
* Gets the literal for a given token.
*
* @param integer $token
*
* @return string
*/
public function getLiteral($token)
{
$className = get_class($this);
$reflClass = new \ReflectionClass($className);
$constants = $reflClass->getConstants();
foreach ($constants as $name => $value) {
if ($value === $token) {
return $className . '::' . $name;
}
}
return $token;
}
/**
* Regex modifiers
*
* @return string
*/
protected function getModifiers()
{
return 'i';
}
/**
* Lexical catchable patterns.
*
* @return array
*/
abstract protected function getCatchablePatterns();
/**
* Lexical non-catchable patterns.
*
* @return array
*/
abstract protected function getNonCatchablePatterns();
/**
* Retrieve token type. Also processes the token value if necessary.
*
* @param string $value
*
* @return integer
*/
abstract protected function getType(&$value);
}