class SassScriptParser in Sassy 7.3
Same name and namespace in other branches
- 7 phamlp/sass/script/SassScriptParser.php \SassScriptParser
SassScriptParser class. Parses SassScript. SassScript is lexed into {@link http://en.wikipedia.org/wiki/Reverse_Polish_notation Reverse Polish notation} by the SassScriptLexer and the calculated result returned. @package PHamlP @subpackage Sass.script
Hierarchy
- class \SassScriptParser
Expanded class hierarchy of SassScriptParser
File
- phpsass/
script/ SassScriptParser.php, line 22
View source
class SassScriptParser {
const MATCH_INTERPOLATION = '/(?<!\\\\)#\\{(.*?)\\}/';
const DEFAULT_ENV = 0;
const CSS_RULE = 1;
const CSS_PROPERTY = 2;
/**
* @var SassContext Used for error reporting
*/
public static $context;
/**
* @var SassScriptLexer the lexer object
*/
public $lexer;
/**
* Hold a copy of a parser available to the general public.
*/
public static $instance;
/**
* SassScriptParser constructor.
* @return SassScriptParser
*/
public function __construct() {
$this->lexer = new SassScriptLexer($this);
self::$instance = $this;
}
/**
* Replace interpolated SassScript contained in '#{}' with the parsed value.
* @param string the text to interpolate
* @param SassContext the context in which the string is interpolated
* @return string the interpolated text
*/
public function interpolate($string, $context) {
for ($i = 0, $n = preg_match_all(self::MATCH_INTERPOLATION, $string, $matches); $i < $n; $i++) {
$var = $this
->evaluate($matches[1][$i], $context)
->toString();
if (preg_match('/^unquote\\((["\'])(.*)\\1\\)$/', $var, $match)) {
$val = $match[2];
}
else {
if ($var == '""') {
$val = "";
}
else {
if (preg_match('/^(["\'])(.*)\\1$/', $var, $match)) {
$val = $match[2];
}
else {
$val = $var;
}
}
}
$matches[1][$i] = $val;
}
return str_replace($matches[0], $matches[1], $string);
}
/**
* Evaluate a SassScript.
* @param string expression to parse
* @param SassContext the context in which the expression is evaluated
* @param integer the environment in which the expression is evaluated
* @return SassLiteral parsed value
*/
public function evaluate($expression, $context, $environment = self::DEFAULT_ENV) {
self::$context = $context;
$operands = array();
$tokens = $this
->parse($expression, $context, $environment);
while (count($tokens)) {
$token = array_shift($tokens);
if ($token instanceof SassScriptFunction) {
array_push($operands, $token
->perform());
}
elseif ($token instanceof SassLiteral) {
if ($token instanceof SassString) {
$token = new SassString($this
->interpolate($token
->toString(), self::$context));
}
array_push($operands, $token);
}
else {
$args = array();
for ($i = 0, $c = $token->operandCount; $i < $c; $i++) {
$args[] = array_pop($operands);
}
array_push($operands, $token
->perform($args));
}
}
return array_shift($operands);
}
/**
* Parse SassScript to a set of tokens in RPN
* using the Shunting Yard Algorithm.
* @param string expression to parse
* @param SassContext the context in which the expression is parsed
* @param integer the environment in which the expression is parsed
* @return array tokens in RPN
*/
public function parse($expression, $context, $environment = self::DEFAULT_ENV) {
$outputQueue = array();
$operatorStack = array();
$parenthesis = 0;
$tokens = $this->lexer
->lex($expression, $context);
foreach ($tokens as $i => $token) {
// If two literals/expessions are seperated by whitespace use the concat operator
if (empty($token)) {
if (isset($tokens[$i + 1])) {
if ($i > 0 && (!$tokens[$i - 1] instanceof SassScriptOperation || $tokens[$i - 1]->operator === SassScriptOperation::$operators[')'][0]) && (!$tokens[$i + 1] instanceof SassScriptOperation || $tokens[$i + 1]->operator === SassScriptOperation::$operators['('][0])) {
$token = new SassScriptOperation(SassScriptOperation::$defaultOperator, $context);
}
else {
continue;
}
}
}
elseif ($token instanceof SassScriptVariable) {
$token = $token
->evaluate($context);
$environment = self::DEFAULT_ENV;
}
// If the token is a number or function add it to the output queue.
if ($token instanceof SassLiteral || $token instanceof SassScriptFunction) {
if ($environment === self::CSS_PROPERTY && $token instanceof SassNumber && !$parenthesis) {
$token->inExpression = false;
}
array_push($outputQueue, $token);
}
elseif ($token instanceof SassScriptOperation) {
// If the token is a left parenthesis push it onto the stack.
if ($token->operator == SassScriptOperation::$operators['('][0]) {
array_push($operatorStack, $token);
$parenthesis++;
}
elseif ($token->operator == SassScriptOperation::$operators[')'][0]) {
$parenthesis--;
while ($c = count($operatorStack)) {
// If the token at the top of the stack is a left parenthesis
if ($operatorStack[$c - 1]->operator == SassScriptOperation::$operators['('][0]) {
// Pop the left parenthesis from the stack, but not onto the output queue.
array_pop($operatorStack);
break;
}
// else pop the operator off the stack onto the output queue.
array_push($outputQueue, array_pop($operatorStack));
}
// If the stack runs out without finding a left parenthesis
// there are mismatched parentheses.
if ($c == 0) {
throw new SassScriptParserException('Unmatched parentheses', $context->node);
}
}
else {
// while there is an operator, o2, at the top of the stack
while ($c = count($operatorStack)) {
$operation = $operatorStack[$c - 1];
// if o2 is left parenthesis, or
// the o1 has left associativty and greater precedence than o2, or
// the o1 has right associativity and lower or equal precedence than o2
if ($operation->operator == SassScriptOperation::$operators['('][0] || $token->associativity == 'l' && $token->precedence > $operation->precedence || $token->associativity == 'r' && $token->precedence <= $operation->precedence) {
break;
// stop checking operators
}
//pop o2 off the stack and onto the output queue
array_push($outputQueue, array_pop($operatorStack));
}
// push o1 onto the stack
array_push($operatorStack, $token);
}
}
}
// When there are no more tokens
while ($c = count($operatorStack)) {
// While there are operators on the stack:
if ($operatorStack[$c - 1]->operator !== SassScriptOperation::$operators['('][0]) {
array_push($outputQueue, array_pop($operatorStack));
}
else {
throw new SassScriptParserException('Unmatched parentheses', $context->node);
}
}
return $outputQueue;
}
}
Members
Name![]() |
Modifiers | Type | Description | Overrides |
---|---|---|---|---|
SassScriptParser:: |
public static | property | ||
SassScriptParser:: |
public static | property | Hold a copy of a parser available to the general public. | |
SassScriptParser:: |
public | property | ||
SassScriptParser:: |
constant | |||
SassScriptParser:: |
constant | |||
SassScriptParser:: |
constant | |||
SassScriptParser:: |
public | function | Evaluate a SassScript. | |
SassScriptParser:: |
public | function | Replace interpolated SassScript contained in '#{}' with the parsed value. | |
SassScriptParser:: |
constant | |||
SassScriptParser:: |
public | function | Parse SassScript to a set of tokens in RPN using the Shunting Yard Algorithm. | |
SassScriptParser:: |
public | function | SassScriptParser constructor. |