silverstripe-framework/core/TokenisedRegularExpression.php

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<?php
/**
* A tokenised regular expression is a parser, similar to a regular expression, that acts on tokens rather than characters.
* This is a crucial component of the ManifestBuilder.
*/
class TokenisedRegularExpression extends Object {
/**
* The regular expression definition
*/
protected $expression;
function __construct($expression) {
$this->expression = $expression;
}
function findAll($tokens) {
$tokenTypes = array();
foreach($tokens as $i => $token) {
if(is_array($token)) {
$tokenTypes[$i] = $token[0];
} else {
$tokenTypes[$i] = $token;
// Pre-process string tokens for matchFrom()
$tokens[$i] = array($token, $token);
}
}
$startKeys = array_keys($tokenTypes, $this->expression[0]);
$allMatches = array();
foreach($startKeys as $startKey) {
$matches = array();
if($this->matchFrom($startKey, 0, $tokens, $matches)) {
$allMatches[] = $matches;
}
}
return $allMatches;
}
function matchFrom($tokenPos, $expressionPos, &$tokens, &$matches) {
$expressionRule = $this->expression[$expressionPos];
$expectation = is_array($expressionRule) ? $expressionRule[0] : $expressionRule;
if(!is_array($expressionRule)) $expressionRule = array();
if($expectation == $tokens[$tokenPos][0]) {
if(isset($expressionRule['save_to'])) {
// Append to an array
if(substr($expressionRule['save_to'],-2) == '[]') $matches[substr($expressionRule['save_to'],0,-2)][] = $tokens[$tokenPos][1];
// Regular variable setting
else $matches[$expressionRule['save_to']] = $tokens[$tokenPos][1];
}
// End of the expression
if(!isset($this->expression[$expressionPos+1])) {
return true;
// Process next step as normal
} else if($this->matchFrom($tokenPos+1, $expressionPos+1, $tokens, $matches)) {
return true;
// This step is optional
} else if(isset($expressionRule['optional']) && $this->matchFrom($tokenPos, $expressionPos+1, $tokens, $matches)) {
return true;
// Process jumps
} else if(isset($expressionRule['can_jump_to'])) {
if(is_array($expressionRule['can_jump_to'])) foreach($expressionRule['can_jump_to'] as $canJumpTo) {
// can_jump_to & optional both set
if(isset($expressionRule['optional']) && $this->matchFrom($tokenPos, $canJumpTo, $tokens, $matches)) {
return true;
}
// can_jump_to set (optional may or may not be set)
if($this->matchFrom($tokenPos+1, $canJumpTo, $tokens, $matches)) {
return true;
}
} else {
// can_jump_to & optional both set
if(isset($expressionRule['optional']) && $this->matchFrom($tokenPos, $expressionRule['can_jump_to'], $tokens, $matches)) {
return true;
}
// can_jump_to set (optional may or may not be set)
if($this->matchFrom($tokenPos+1, $expressionRule['can_jump_to'], $tokens, $matches)) {
return true;
}
}
}
} else if(isset($expressionRule['optional'])) {
if(isset($this->expression[$expressionPos+1])) return $this->matchFrom($tokenPos, $expressionPos+1, $tokens, $matches);
else return true;
}
return false;
}
}