465 lines
19 KiB
PHP
465 lines
19 KiB
PHP
<?php
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namespace PhpParser;
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/*
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* This parser is based on a skeleton written by Moriyoshi Koizumi, which in
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* turn is based on work by Masato Bito.
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*/
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abstract class ParserAbstract
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{
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const SYMBOL_NONE = -1;
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/*
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* The following members will be filled with generated parsing data:
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*/
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/** @var int Size of $tokenToSymbol map */
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protected $tokenToSymbolMapSize;
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/** @var int Size of $action table */
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protected $actionTableSize;
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/** @var int Size of $goto table */
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protected $gotoTableSize;
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/** @var int Symbol number signifying an invalid token */
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protected $invalidSymbol;
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/** @var int Symbol number of error recovery token */
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protected $errorSymbol;
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/** @var int Action number signifying default action */
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protected $defaultAction;
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/** @var int Rule number signifying that an unexpected token was encountered */
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protected $unexpectedTokenRule;
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protected $YY2TBLSTATE;
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protected $YYNLSTATES;
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/** @var array Map of lexer tokens to internal symbols */
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protected $tokenToSymbol;
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/** @var array Map of symbols to their names */
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protected $symbolToName;
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/** @var array Names of the production rules (only necessary for debugging) */
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protected $productions;
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/** @var array Map of states to a displacement into the $action table. The corresponding action for this
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* state/symbol pair is $action[$actionBase[$state] + $symbol]. If $actionBase[$state] is 0, the
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action is defaulted, i.e. $actionDefault[$state] should be used instead. */
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protected $actionBase;
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/** @var array Table of actions. Indexed according to $actionBase comment. */
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protected $action;
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/** @var array Table indexed analogously to $action. If $actionCheck[$actionBase[$state] + $symbol] != $symbol
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* then the action is defaulted, i.e. $actionDefault[$state] should be used instead. */
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protected $actionCheck;
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/** @var array Map of states to their default action */
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protected $actionDefault;
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/** @var array Map of non-terminals to a displacement into the $goto table. The corresponding goto state for this
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* non-terminal/state pair is $goto[$gotoBase[$nonTerminal] + $state] (unless defaulted) */
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protected $gotoBase;
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/** @var array Table of states to goto after reduction. Indexed according to $gotoBase comment. */
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protected $goto;
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/** @var array Table indexed analogously to $goto. If $gotoCheck[$gotoBase[$nonTerminal] + $state] != $nonTerminal
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* then the goto state is defaulted, i.e. $gotoDefault[$nonTerminal] should be used. */
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protected $gotoCheck;
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/** @var array Map of non-terminals to the default state to goto after their reduction */
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protected $gotoDefault;
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/** @var array Map of rules to the non-terminal on their left-hand side, i.e. the non-terminal to use for
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* determining the state to goto after reduction. */
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protected $ruleToNonTerminal;
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/** @var array Map of rules to the length of their right-hand side, which is the number of elements that have to
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* be popped from the stack(s) on reduction. */
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protected $ruleToLength;
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/*
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* The following members are part of the parser state:
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*/
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/** @var Lexer Lexer that is used when parsing */
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protected $lexer;
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/** @var mixed Temporary value containing the result of last semantic action (reduction) */
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protected $semValue;
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/** @var int Position in stacks (state stack, semantic value stack, attribute stack) */
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protected $stackPos;
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/** @var array Semantic value stack (contains values of tokens and semantic action results) */
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protected $semStack;
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/** @var array[] Start attribute stack */
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protected $startAttributeStack;
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/** @var array End attributes of last *shifted* token */
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protected $endAttributes;
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/** @var bool Whether to throw on first error */
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protected $throwOnError;
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/** @var Error[] Errors collected during last parse */
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protected $errors;
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/**
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* Creates a parser instance.
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*
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* @param Lexer $lexer A lexer
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* @param array $options Options array. The boolean 'throwOnError' option determines whether an exception should be
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* thrown on first error, or if the parser should try to continue parsing the remaining code
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* and build a partial AST.
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*/
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public function __construct(Lexer $lexer, array $options = array()) {
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$this->lexer = $lexer;
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$this->errors = array();
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$this->throwOnError = isset($options['throwOnError']) ? $options['throwOnError'] : true;
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}
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/**
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* Get array of errors that occurred during the last parse.
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*
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* This method may only return multiple errors if the 'throwOnError' option is disabled.
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*
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* @return Error[]
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*/
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public function getErrors() {
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return $this->errors;
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}
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/**
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* Parses PHP code into a node tree.
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*
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* @param string $code The source code to parse
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*
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* @return Node[]|null Array of statements (or null if the 'throwOnError' option is disabled and the parser was
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* unable to recover from an error).
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*/
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public function parse($code) {
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$this->lexer->startLexing($code);
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$this->errors = array();
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// We start off with no lookahead-token
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$symbol = self::SYMBOL_NONE;
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// The attributes for a node are taken from the first and last token of the node.
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// From the first token only the startAttributes are taken and from the last only
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// the endAttributes. Both are merged using the array union operator (+).
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$startAttributes = '*POISON';
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$endAttributes = '*POISON';
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$this->endAttributes = $endAttributes;
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// In order to figure out the attributes for the starting token, we have to keep
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// them in a stack
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$this->startAttributeStack = array();
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// Start off in the initial state and keep a stack of previous states
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$state = 0;
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$stateStack = array($state);
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// Semantic value stack (contains values of tokens and semantic action results)
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$this->semStack = array();
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// Current position in the stack(s)
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$this->stackPos = 0;
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$errorState = 0;
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for (;;) {
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//$this->traceNewState($state, $symbol);
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if ($this->actionBase[$state] == 0) {
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$rule = $this->actionDefault[$state];
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} else {
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if ($symbol === self::SYMBOL_NONE) {
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// Fetch the next token id from the lexer and fetch additional info by-ref.
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// The end attributes are fetched into a temporary variable and only set once the token is really
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// shifted (not during read). Otherwise you would sometimes get off-by-one errors, when a rule is
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// reduced after a token was read but not yet shifted.
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$tokenId = $this->lexer->getNextToken($tokenValue, $startAttributes, $endAttributes);
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// map the lexer token id to the internally used symbols
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$symbol = $tokenId >= 0 && $tokenId < $this->tokenToSymbolMapSize
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? $this->tokenToSymbol[$tokenId]
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: $this->invalidSymbol;
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if ($symbol === $this->invalidSymbol) {
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throw new \RangeException(sprintf(
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'The lexer returned an invalid token (id=%d, value=%s)',
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$tokenId, $tokenValue
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));
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}
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// This is necessary to assign some meaningful attributes to /* empty */ productions. They'll get
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// the attributes of the next token, even though they don't contain it themselves.
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$this->startAttributeStack[$this->stackPos+1] = $startAttributes;
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//$this->traceRead($symbol);
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}
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$idx = $this->actionBase[$state] + $symbol;
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if ((($idx >= 0 && $idx < $this->actionTableSize && $this->actionCheck[$idx] == $symbol)
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|| ($state < $this->YY2TBLSTATE
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&& ($idx = $this->actionBase[$state + $this->YYNLSTATES] + $symbol) >= 0
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&& $idx < $this->actionTableSize && $this->actionCheck[$idx] == $symbol))
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&& ($action = $this->action[$idx]) != $this->defaultAction) {
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/*
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* >= YYNLSTATES: shift and reduce
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* > 0: shift
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* = 0: accept
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* < 0: reduce
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* = -YYUNEXPECTED: error
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*/
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if ($action > 0) {
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/* shift */
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//$this->traceShift($symbol);
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++$this->stackPos;
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$stateStack[$this->stackPos] = $state = $action;
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$this->semStack[$this->stackPos] = $tokenValue;
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$this->startAttributeStack[$this->stackPos] = $startAttributes;
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$this->endAttributes = $endAttributes;
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$symbol = self::SYMBOL_NONE;
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if ($errorState) {
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--$errorState;
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}
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if ($action < $this->YYNLSTATES) {
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continue;
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}
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/* $yyn >= YYNLSTATES means shift-and-reduce */
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$rule = $action - $this->YYNLSTATES;
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} else {
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$rule = -$action;
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}
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} else {
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$rule = $this->actionDefault[$state];
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}
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}
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for (;;) {
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if ($rule === 0) {
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/* accept */
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//$this->traceAccept();
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return $this->semValue;
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} elseif ($rule !== $this->unexpectedTokenRule) {
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/* reduce */
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//$this->traceReduce($rule);
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try {
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$this->{'reduceRule' . $rule}();
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} catch (Error $e) {
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if (-1 === $e->getStartLine() && isset($startAttributes['startLine'])) {
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$e->setStartLine($startAttributes['startLine']);
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}
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$this->errors[] = $e;
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if ($this->throwOnError) {
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throw $e;
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} else {
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// Currently can't recover from "special" errors
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return null;
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}
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}
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/* Goto - shift nonterminal */
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$this->stackPos -= $this->ruleToLength[$rule];
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$nonTerminal = $this->ruleToNonTerminal[$rule];
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$idx = $this->gotoBase[$nonTerminal] + $stateStack[$this->stackPos];
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if ($idx >= 0 && $idx < $this->gotoTableSize && $this->gotoCheck[$idx] == $nonTerminal) {
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$state = $this->goto[$idx];
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} else {
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$state = $this->gotoDefault[$nonTerminal];
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}
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++$this->stackPos;
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$stateStack[$this->stackPos] = $state;
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$this->semStack[$this->stackPos] = $this->semValue;
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} else {
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/* error */
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switch ($errorState) {
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case 0:
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$msg = $this->getErrorMessage($symbol, $state);
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$error = new Error($msg, $startAttributes + $endAttributes);
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$this->errors[] = $error;
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if ($this->throwOnError) {
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throw $error;
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}
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// Break missing intentionally
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case 1:
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case 2:
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$errorState = 3;
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// Pop until error-expecting state uncovered
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while (!(
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(($idx = $this->actionBase[$state] + $this->errorSymbol) >= 0
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&& $idx < $this->actionTableSize && $this->actionCheck[$idx] == $this->errorSymbol)
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|| ($state < $this->YY2TBLSTATE
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&& ($idx = $this->actionBase[$state + $this->YYNLSTATES] + $this->errorSymbol) >= 0
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&& $idx < $this->actionTableSize && $this->actionCheck[$idx] == $this->errorSymbol)
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) || ($action = $this->action[$idx]) == $this->defaultAction) { // Not totally sure about this
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if ($this->stackPos <= 0) {
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// Could not recover from error
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return null;
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}
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$state = $stateStack[--$this->stackPos];
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//$this->tracePop($state);
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}
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//$this->traceShift($this->errorSymbol);
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$stateStack[++$this->stackPos] = $state = $action;
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break;
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case 3:
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if ($symbol === 0) {
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// Reached EOF without recovering from error
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return null;
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}
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//$this->traceDiscard($symbol);
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$symbol = self::SYMBOL_NONE;
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break 2;
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}
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}
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if ($state < $this->YYNLSTATES) {
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break;
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}
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/* >= YYNLSTATES means shift-and-reduce */
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$rule = $state - $this->YYNLSTATES;
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}
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}
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throw new \RuntimeException('Reached end of parser loop');
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}
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protected function getErrorMessage($symbol, $state) {
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$expectedString = '';
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if ($expected = $this->getExpectedTokens($state)) {
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$expectedString = ', expecting ' . implode(' or ', $expected);
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}
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return 'Syntax error, unexpected ' . $this->symbolToName[$symbol] . $expectedString;
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}
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protected function getExpectedTokens($state) {
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$expected = array();
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$base = $this->actionBase[$state];
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foreach ($this->symbolToName as $symbol => $name) {
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$idx = $base + $symbol;
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if ($idx >= 0 && $idx < $this->actionTableSize && $this->actionCheck[$idx] === $symbol
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|| $state < $this->YY2TBLSTATE
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&& ($idx = $this->actionBase[$state + $this->YYNLSTATES] + $symbol) >= 0
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&& $idx < $this->actionTableSize && $this->actionCheck[$idx] === $symbol
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) {
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if ($this->action[$idx] != $this->unexpectedTokenRule) {
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if (count($expected) == 4) {
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/* Too many expected tokens */
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return array();
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}
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$expected[] = $name;
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}
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}
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}
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return $expected;
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}
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/*
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* Tracing functions used for debugging the parser.
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*/
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/*
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protected function traceNewState($state, $symbol) {
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echo '% State ' . $state
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. ', Lookahead ' . ($symbol == self::SYMBOL_NONE ? '--none--' : $this->symbolToName[$symbol]) . "\n";
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}
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protected function traceRead($symbol) {
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echo '% Reading ' . $this->symbolToName[$symbol] . "\n";
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}
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protected function traceShift($symbol) {
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echo '% Shift ' . $this->symbolToName[$symbol] . "\n";
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}
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protected function traceAccept() {
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echo "% Accepted.\n";
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}
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protected function traceReduce($n) {
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echo '% Reduce by (' . $n . ') ' . $this->productions[$n] . "\n";
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}
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protected function tracePop($state) {
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echo '% Recovering, uncovered state ' . $state . "\n";
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}
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protected function traceDiscard($symbol) {
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echo '% Discard ' . $this->symbolToName[$symbol] . "\n";
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}
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*/
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/*
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* Helper functions invoked by semantic actions
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*/
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/**
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* Moves statements of semicolon-style namespaces into $ns->stmts and checks various error conditions.
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*
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* @param Node[] $stmts
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* @return Node[]
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*/
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protected function handleNamespaces(array $stmts) {
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$style = $this->getNamespacingStyle($stmts);
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if (null === $style) {
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// not namespaced, nothing to do
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return $stmts;
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} elseif ('brace' === $style) {
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// For braced namespaces we only have to check that there are no invalid statements between the namespaces
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$afterFirstNamespace = false;
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foreach ($stmts as $stmt) {
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if ($stmt instanceof Node\Stmt\Namespace_) {
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$afterFirstNamespace = true;
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} elseif (!$stmt instanceof Node\Stmt\HaltCompiler && $afterFirstNamespace) {
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throw new Error('No code may exist outside of namespace {}', $stmt->getLine());
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}
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}
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return $stmts;
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} else {
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// For semicolon namespaces we have to move the statements after a namespace declaration into ->stmts
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$resultStmts = array();
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$targetStmts =& $resultStmts;
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foreach ($stmts as $stmt) {
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if ($stmt instanceof Node\Stmt\Namespace_) {
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$stmt->stmts = array();
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$targetStmts =& $stmt->stmts;
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$resultStmts[] = $stmt;
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} elseif ($stmt instanceof Node\Stmt\HaltCompiler) {
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// __halt_compiler() is not moved into the namespace
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$resultStmts[] = $stmt;
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} else {
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$targetStmts[] = $stmt;
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}
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}
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return $resultStmts;
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}
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}
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private function getNamespacingStyle(array $stmts) {
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$style = null;
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$hasNotAllowedStmts = false;
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foreach ($stmts as $stmt) {
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if ($stmt instanceof Node\Stmt\Namespace_) {
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$currentStyle = null === $stmt->stmts ? 'semicolon' : 'brace';
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if (null === $style) {
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$style = $currentStyle;
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if ($hasNotAllowedStmts) {
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throw new Error('Namespace declaration statement has to be the very first statement in the script', $stmt->getLine());
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}
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} elseif ($style !== $currentStyle) {
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throw new Error('Cannot mix bracketed namespace declarations with unbracketed namespace declarations', $stmt->getLine());
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}
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} elseif (!$stmt instanceof Node\Stmt\Declare_ && !$stmt instanceof Node\Stmt\HaltCompiler) {
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$hasNotAllowedStmts = true;
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}
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}
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return $style;
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}
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}
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