<?php declare(strict_types=1);

namespace PhpParser;

/*
 * This parser is based on a skeleton written by Moriyoshi Koizumi, which in
 * turn is based on work by Masato Bito.
 */

use PhpParser\Node\Expr;
use PhpParser\Node\Expr\Array_;
use PhpParser\Node\Expr\Cast\Double;
use PhpParser\Node\Identifier;
use PhpParser\Node\InterpolatedStringPart;
use PhpParser\Node\Name;
use PhpParser\Node\Param;
use PhpParser\Node\Scalar\InterpolatedString;
use PhpParser\Node\Scalar\Int_;
use PhpParser\Node\Scalar\String_;
use PhpParser\Node\Stmt;
use PhpParser\Node\Stmt\Class_;
use PhpParser\Node\Stmt\ClassConst;
use PhpParser\Node\Stmt\ClassMethod;
use PhpParser\Node\Stmt\Else_;
use PhpParser\Node\Stmt\ElseIf_;
use PhpParser\Node\Stmt\Enum_;
use PhpParser\Node\Stmt\Interface_;
use PhpParser\Node\Stmt\Namespace_;
use PhpParser\Node\Stmt\Nop;
use PhpParser\Node\Stmt\Property;
use PhpParser\Node\Stmt\TryCatch;
use PhpParser\Node\UseItem;
use PhpParser\NodeVisitor\CommentAnnotatingVisitor;

abstract class ParserAbstract implements Parser {
    private const SYMBOL_NONE = -1;

    /** @var Lexer Lexer that is used when parsing */
    protected Lexer $lexer;
    /** @var PhpVersion PHP version to target on a best-effort basis */
    protected PhpVersion $phpVersion;

    /*
     * The following members will be filled with generated parsing data:
     */

    /** @var int Size of $tokenToSymbol map */
    protected int $tokenToSymbolMapSize;
    /** @var int Size of $action table */
    protected int $actionTableSize;
    /** @var int Size of $goto table */
    protected int $gotoTableSize;

    /** @var int Symbol number signifying an invalid token */
    protected int $invalidSymbol;
    /** @var int Symbol number of error recovery token */
    protected int $errorSymbol;
    /** @var int Action number signifying default action */
    protected int $defaultAction;
    /** @var int Rule number signifying that an unexpected token was encountered */
    protected int $unexpectedTokenRule;

    protected int $YY2TBLSTATE;
    /** @var int Number of non-leaf states */
    protected int $numNonLeafStates;

    /** @var int[] Map of PHP token IDs to internal symbols */
    protected array $phpTokenToSymbol;
    /** @var array<int, bool> Map of PHP token IDs to drop */
    protected array $dropTokens;
    /** @var int[] Map of external symbols (static::T_*) to internal symbols */
    protected array $tokenToSymbol;
    /** @var string[] Map of symbols to their names */
    protected array $symbolToName;
    /** @var array<int, string> Names of the production rules (only necessary for debugging) */
    protected array $productions;

    /** @var int[] Map of states to a displacement into the $action table. The corresponding action for this
     *             state/symbol pair is $action[$actionBase[$state] + $symbol]. If $actionBase[$state] is 0, the
     *             action is defaulted, i.e. $actionDefault[$state] should be used instead. */
    protected array $actionBase;
    /** @var int[] Table of actions. Indexed according to $actionBase comment. */
    protected array $action;
    /** @var int[] Table indexed analogously to $action. If $actionCheck[$actionBase[$state] + $symbol] != $symbol
     *             then the action is defaulted, i.e. $actionDefault[$state] should be used instead. */
    protected array $actionCheck;
    /** @var int[] Map of states to their default action */
    protected array $actionDefault;
    /** @var callable[] Semantic action callbacks */
    protected array $reduceCallbacks;

    /** @var int[] Map of non-terminals to a displacement into the $goto table. The corresponding goto state for this
     *             non-terminal/state pair is $goto[$gotoBase[$nonTerminal] + $state] (unless defaulted) */
    protected array $gotoBase;
    /** @var int[] Table of states to goto after reduction. Indexed according to $gotoBase comment. */
    protected array $goto;
    /** @var int[] Table indexed analogously to $goto. If $gotoCheck[$gotoBase[$nonTerminal] + $state] != $nonTerminal
     *             then the goto state is defaulted, i.e. $gotoDefault[$nonTerminal] should be used. */
    protected array $gotoCheck;
    /** @var int[] Map of non-terminals to the default state to goto after their reduction */
    protected array $gotoDefault;

    /** @var int[] Map of rules to the non-terminal on their left-hand side, i.e. the non-terminal to use for
     *             determining the state to goto after reduction. */
    protected array $ruleToNonTerminal;
    /** @var int[] Map of rules to the length of their right-hand side, which is the number of elements that have to
     *             be popped from the stack(s) on reduction. */
    protected array $ruleToLength;

    /*
     * The following members are part of the parser state:
     */

    /** @var mixed Temporary value containing the result of last semantic action (reduction) */
    protected $semValue;
    /** @var mixed[] Semantic value stack (contains values of tokens and semantic action results) */
    protected array $semStack;
    /** @var int[] Token start position stack */
    protected array $tokenStartStack;
    /** @var int[] Token end position stack */
    protected array $tokenEndStack;

    /** @var ErrorHandler Error handler */
    protected ErrorHandler $errorHandler;
    /** @var int Error state, used to avoid error floods */
    protected int $errorState;

    /** @var \SplObjectStorage<Array_, null>|null Array nodes created during parsing, for postprocessing of empty elements. */
    protected ?\SplObjectStorage $createdArrays;

    /** @var Token[] Tokens for the current parse */
    protected array $tokens;
    /** @var int Current position in token array */
    protected int $tokenPos;

    /**
     * Initialize $reduceCallbacks map.
     */
    abstract protected function initReduceCallbacks(): void;

    /**
     * Creates a parser instance.
     *
     * Options:
     *  * phpVersion: ?PhpVersion,
     *
     * @param Lexer $lexer A lexer
     * @param PhpVersion $phpVersion PHP version to target, defaults to latest supported. This
     *                               option is best-effort: Even if specified, parsing will generally assume the latest
     *                               supported version and only adjust behavior in minor ways, for example by omitting
     *                               errors in older versions and interpreting type hints as a name or identifier depending
     *                               on version.
     */
    public function __construct(Lexer $lexer, ?PhpVersion $phpVersion = null) {
        $this->lexer = $lexer;
        $this->phpVersion = $phpVersion ?? PhpVersion::getNewestSupported();

        $this->initReduceCallbacks();
        $this->phpTokenToSymbol = $this->createTokenMap();
        $this->dropTokens = array_fill_keys(
            [\T_WHITESPACE, \T_OPEN_TAG, \T_COMMENT, \T_DOC_COMMENT, \T_BAD_CHARACTER], true
        );
    }

    /**
     * Parses PHP code into a node tree.
     *
     * If a non-throwing error handler is used, the parser will continue parsing after an error
     * occurred and attempt to build a partial AST.
     *
     * @param string $code The source code to parse
     * @param ErrorHandler|null $errorHandler Error handler to use for lexer/parser errors, defaults
     *                                        to ErrorHandler\Throwing.
     *
     * @return Node\Stmt[]|null Array of statements (or null non-throwing error handler is used and
     *                          the parser was unable to recover from an error).
     */
    public function parse(string $code, ?ErrorHandler $errorHandler = null): ?array {
        $this->errorHandler = $errorHandler ?: new ErrorHandler\Throwing();
        $this->createdArrays = new \SplObjectStorage();

        $this->tokens = $this->lexer->tokenize($code, $this->errorHandler);
        $result = $this->doParse();

        // Report errors for any empty elements used inside arrays. This is delayed until after the main parse,
        // because we don't know a priori whether a given array expression will be used in a destructuring context
        // or not.
        foreach ($this->createdArrays as $node) {
            foreach ($node->items as $item) {
                if ($item->value instanceof Expr\Error) {
                    $this->errorHandler->handleError(
                        new Error('Cannot use empty array elements in arrays', $item->getAttributes()));
                }
            }
        }

        // Clear out some of the interior state, so we don't hold onto unnecessary
        // memory between uses of the parser
        $this->tokenStartStack = [];
        $this->tokenEndStack = [];
        $this->semStack = [];
        $this->semValue = null;
        $this->createdArrays = null;

        if ($result !== null) {
            $traverser = new NodeTraverser(new CommentAnnotatingVisitor($this->tokens));
            $traverser->traverse($result);
        }

        return $result;
    }

    public function getTokens(): array {
        return $this->tokens;
    }

    /** @return Stmt[]|null */
    protected function doParse(): ?array {
        // We start off with no lookahead-token
        $symbol = self::SYMBOL_NONE;
        $tokenValue = null;
        $this->tokenPos = -1;

        // Keep stack of start and end attributes
        $this->tokenStartStack = [];
        $this->tokenEndStack = [0];

        // Start off in the initial state and keep a stack of previous states
        $state = 0;
        $stateStack = [$state];

        // Semantic value stack (contains values of tokens and semantic action results)
        $this->semStack = [];

        // Current position in the stack(s)
        $stackPos = 0;

        $this->errorState = 0;

        for (;;) {
            //$this->traceNewState($state, $symbol);

            if ($this->actionBase[$state] === 0) {
                $rule = $this->actionDefault[$state];
            } else {
                if ($symbol === self::SYMBOL_NONE) {
                    do {
                        $token = $this->tokens[++$this->tokenPos];
                        $tokenId = $token->id;
                    } while (isset($this->dropTokens[$tokenId]));

                    // Map the lexer token id to the internally used symbols.
                    $tokenValue = $token->text;
                    if (!isset($this->phpTokenToSymbol[$tokenId])) {
                        throw new \RangeException(sprintf(
                            'The lexer returned an invalid token (id=%d, value=%s)',
                            $tokenId, $tokenValue
                        ));
                    }
                    $symbol = $this->phpTokenToSymbol[$tokenId];

                    //$this->traceRead($symbol);
                }

                $idx = $this->actionBase[$state] + $symbol;
                if ((($idx >= 0 && $idx < $this->actionTableSize && $this->actionCheck[$idx] === $symbol)
                     || ($state < $this->YY2TBLSTATE
                         && ($idx = $this->actionBase[$state + $this->numNonLeafStates] + $symbol) >= 0
                         && $idx < $this->actionTableSize && $this->actionCheck[$idx] === $symbol))
                    && ($action = $this->action[$idx]) !== $this->defaultAction) {
                    /*
                     * >= numNonLeafStates: shift and reduce
                     * > 0: shift
                     * = 0: accept
                     * < 0: reduce
                     * = -YYUNEXPECTED: error
                     */
                    if ($action > 0) {
                        /* shift */
                        //$this->traceShift($symbol);

                        ++$stackPos;
                        $stateStack[$stackPos] = $state = $action;
                        $this->semStack[$stackPos] = $tokenValue;
                        $this->tokenStartStack[$stackPos] = $this->tokenPos;
                        $this->tokenEndStack[$stackPos] = $this->tokenPos;
                        $symbol = self::SYMBOL_NONE;

                        if ($this->errorState) {
                            --$this->errorState;
                        }

                        if ($action < $this->numNonLeafStates) {
                            continue;
                        }

                        /* $yyn >= numNonLeafStates means shift-and-reduce */
                        $rule = $action - $this->numNonLeafStates;
                    } else {
                        $rule = -$action;
                    }
                } else {
                    $rule = $this->actionDefault[$state];
                }
            }

            for (;;) {
                if ($rule === 0) {
                    /* accept */
                    //$this->traceAccept();
                    return $this->semValue;
                }
                if ($rule !== $this->unexpectedTokenRule) {
                    /* reduce */
                    //$this->traceReduce($rule);

                    $ruleLength = $this->ruleToLength[$rule];
                    try {
                        $callback = $this->reduceCallbacks[$rule];
                        if ($callback !== null) {
                            $callback($this, $stackPos);
                        } elseif ($ruleLength > 0) {
                            $this->semValue = $this->semStack[$stackPos - $ruleLength + 1];
                        }
                    } catch (Error $e) {
                        if (-1 === $e->getStartLine()) {
                            $e->setStartLine($this->tokens[$this->tokenPos]->line);
                        }

                        $this->emitError($e);
                        // Can't recover from this type of error
                        return null;
                    }

                    /* Goto - shift nonterminal */
                    $lastTokenEnd = $this->tokenEndStack[$stackPos];
                    $stackPos -= $ruleLength;
                    $nonTerminal = $this->ruleToNonTerminal[$rule];
                    $idx = $this->gotoBase[$nonTerminal] + $stateStack[$stackPos];
                    if ($idx >= 0 && $idx < $this->gotoTableSize && $this->gotoCheck[$idx] === $nonTerminal) {
                        $state = $this->goto[$idx];
                    } else {
                        $state = $this->gotoDefault[$nonTerminal];
                    }

                    ++$stackPos;
                    $stateStack[$stackPos]     = $state;
                    $this->semStack[$stackPos] = $this->semValue;
                    $this->tokenEndStack[$stackPos] = $lastTokenEnd;
                    if ($ruleLength === 0) {
                        // Empty productions use the start attributes of the lookahead token.
                        $this->tokenStartStack[$stackPos] = $this->tokenPos;
                    }
                } else {
                    /* error */
                    switch ($this->errorState) {
                        case 0:
                            $msg = $this->getErrorMessage($symbol, $state);
                            $this->emitError(new Error($msg, $this->getAttributesForToken($this->tokenPos)));
                            // Break missing intentionally
                            // no break
                        case 1:
                        case 2:
                            $this->errorState = 3;

                            // Pop until error-expecting state uncovered
                            while (!(
                                (($idx = $this->actionBase[$state] + $this->errorSymbol) >= 0
                                    && $idx < $this->actionTableSize && $this->actionCheck[$idx] === $this->errorSymbol)
                                || ($state < $this->YY2TBLSTATE
                                    && ($idx = $this->actionBase[$state + $this->numNonLeafStates] + $this->errorSymbol) >= 0
                                    && $idx < $this->actionTableSize && $this->actionCheck[$idx] === $this->errorSymbol)
                            ) || ($action = $this->action[$idx]) === $this->defaultAction) { // Not totally sure about this
                                if ($stackPos <= 0) {
                                    // Could not recover from error
                                    return null;
                                }
                                $state = $stateStack[--$stackPos];
                                //$this->tracePop($state);
                            }

                            //$this->traceShift($this->errorSymbol);
                            ++$stackPos;
                            $stateStack[$stackPos] = $state = $action;

                            // We treat the error symbol as being empty, so we reset the end attributes
                            // to the end attributes of the last non-error symbol
                            $this->tokenStartStack[$stackPos] = $this->tokenPos;
                            $this->tokenEndStack[$stackPos] = $this->tokenEndStack[$stackPos - 1];
                            break;

                        case 3:
                            if ($symbol === 0) {
                                // Reached EOF without recovering from error
                                return null;
                            }

                            //$this->traceDiscard($symbol);
                            $symbol = self::SYMBOL_NONE;
                            break 2;
                    }
                }

                if ($state < $this->numNonLeafStates) {
                    break;
                }

                /* >= numNonLeafStates means shift-and-reduce */
                $rule = $state - $this->numNonLeafStates;
            }
        }

        throw new \RuntimeException('Reached end of parser loop');
    }

    protected function emitError(Error $error): void {
        $this->errorHandler->handleError($error);
    }

    /**
     * Format error message including expected tokens.
     *
     * @param int $symbol Unexpected symbol
     * @param int $state State at time of error
     *
     * @return string Formatted error message
     */
    protected function getErrorMessage(int $symbol, int $state): string {
        $expectedString = '';
        if ($expected = $this->getExpectedTokens($state)) {
            $expectedString = ', expecting ' . implode(' or ', $expected);
        }

        return 'Syntax error, unexpected ' . $this->symbolToName[$symbol] . $expectedString;
    }

    /**
     * Get limited number of expected tokens in given state.
     *
     * @param int $state State
     *
     * @return string[] Expected tokens. If too many, an empty array is returned.
     */
    protected function getExpectedTokens(int $state): array {
        $expected = [];

        $base = $this->actionBase[$state];
        foreach ($this->symbolToName as $symbol => $name) {
            $idx = $base + $symbol;
            if ($idx >= 0 && $idx < $this->actionTableSize && $this->actionCheck[$idx] === $symbol
                || $state < $this->YY2TBLSTATE
                && ($idx = $this->actionBase[$state + $this->numNonLeafStates] + $symbol) >= 0
                && $idx < $this->actionTableSize && $this->actionCheck[$idx] === $symbol
            ) {
                if ($this->action[$idx] !== $this->unexpectedTokenRule
                    && $this->action[$idx] !== $this->defaultAction
                    && $symbol !== $this->errorSymbol
                ) {
                    if (count($expected) === 4) {
                        /* Too many expected tokens */
                        return [];
                    }

                    $expected[] = $name;
                }
            }
        }

        return $expected;
    }

    /**
     * Get attributes for a node with the given start and end token positions.
     *
     * @param int $tokenStartPos Token position the node starts at
     * @param int $tokenEndPos Token position the node ends at
     * @return array<string, mixed> Attributes
     */
    protected function getAttributes(int $tokenStartPos, int $tokenEndPos): array {
        $startToken = $this->tokens[$tokenStartPos];
        $afterEndToken = $this->tokens[$tokenEndPos + 1];
        return [
            'startLine' => $startToken->line,
            'startTokenPos' => $tokenStartPos,
            'startFilePos' => $startToken->pos,
            'endLine' => $afterEndToken->line,
            'endTokenPos' => $tokenEndPos,
            'endFilePos' => $afterEndToken->pos - 1,
        ];
    }

    /**
     * Get attributes for a single token at the given token position.
     *
     * @return array<string, mixed> Attributes
     */
    protected function getAttributesForToken(int $tokenPos): array {
        if ($tokenPos < \count($this->tokens) - 1) {
            return $this->getAttributes($tokenPos, $tokenPos);
        }

        // Get attributes for the sentinel token.
        $token = $this->tokens[$tokenPos];
        return [
            'startLine' => $token->line,
            'startTokenPos' => $tokenPos,
            'startFilePos' => $token->pos,
            'endLine' => $token->line,
            'endTokenPos' => $tokenPos,
            'endFilePos' => $token->pos,
        ];
    }

    /*
     * Tracing functions used for debugging the parser.
     */

    /*
    protected function traceNewState($state, $symbol): void {
        echo '% State ' . $state
            . ', Lookahead ' . ($symbol == self::SYMBOL_NONE ? '--none--' : $this->symbolToName[$symbol]) . "\n";
    }

    protected function traceRead($symbol): void {
        echo '% Reading ' . $this->symbolToName[$symbol] . "\n";
    }

    protected function traceShift($symbol): void {
        echo '% Shift ' . $this->symbolToName[$symbol] . "\n";
    }

    protected function traceAccept(): void {
        echo "% Accepted.\n";
    }

    protected function traceReduce($n): void {
        echo '% Reduce by (' . $n . ') ' . $this->productions[$n] . "\n";
    }

    protected function tracePop($state): void {
        echo '% Recovering, uncovered state ' . $state . "\n";
    }

    protected function traceDiscard($symbol): void {
        echo '% Discard ' . $this->symbolToName[$symbol] . "\n";
    }
    */

    /*
     * Helper functions invoked by semantic actions
     */

    /**
     * Moves statements of semicolon-style namespaces into $ns->stmts and checks various error conditions.
     *
     * @param Node\Stmt[] $stmts
     * @return Node\Stmt[]
     */
    protected function handleNamespaces(array $stmts): array {
        $hasErrored = false;
        $style = $this->getNamespacingStyle($stmts);
        if (null === $style) {
            // not namespaced, nothing to do
            return $stmts;
        }
        if ('brace' === $style) {
            // For braced namespaces we only have to check that there are no invalid statements between the namespaces
            $afterFirstNamespace = false;
            foreach ($stmts as $stmt) {
                if ($stmt instanceof Node\Stmt\Namespace_) {
                    $afterFirstNamespace = true;
                } elseif (!$stmt instanceof Node\Stmt\HaltCompiler
                        && !$stmt instanceof Node\Stmt\Nop
                        && $afterFirstNamespace && !$hasErrored) {
                    $this->emitError(new Error(
                        'No code may exist outside of namespace {}', $stmt->getAttributes()));
                    $hasErrored = true; // Avoid one error for every statement
                }
            }
            return $stmts;
        } else {
            // For semicolon namespaces we have to move the statements after a namespace declaration into ->stmts
            $resultStmts = [];
            $targetStmts = &$resultStmts;
            $lastNs = null;
            foreach ($stmts as $stmt) {
                if ($stmt instanceof Node\Stmt\Namespace_) {
                    if ($lastNs !== null) {
                        $this->fixupNamespaceAttributes($lastNs);
                    }
                    if ($stmt->stmts === null) {
                        $stmt->stmts = [];
                        $targetStmts = &$stmt->stmts;
                        $resultStmts[] = $stmt;
                    } else {
                        // This handles the invalid case of mixed style namespaces
                        $resultStmts[] = $stmt;
                        $targetStmts = &$resultStmts;
                    }
                    $lastNs = $stmt;
                } elseif ($stmt instanceof Node\Stmt\HaltCompiler) {
                    // __halt_compiler() is not moved into the namespace
                    $resultStmts[] = $stmt;
                } else {
                    $targetStmts[] = $stmt;
                }
            }
            if ($lastNs !== null) {
                $this->fixupNamespaceAttributes($lastNs);
            }
            return $resultStmts;
        }
    }

    private function fixupNamespaceAttributes(Node\Stmt\Namespace_ $stmt): void {
        // We moved the statements into the namespace node, as such the end of the namespace node
        // needs to be extended to the end of the statements.
        if (empty($stmt->stmts)) {
            return;
        }

        // We only move the builtin end attributes here. This is the best we can do with the
        // knowledge we have.
        $endAttributes = ['endLine', 'endFilePos', 'endTokenPos'];
        $lastStmt = $stmt->stmts[count($stmt->stmts) - 1];
        foreach ($endAttributes as $endAttribute) {
            if ($lastStmt->hasAttribute($endAttribute)) {
                $stmt->setAttribute($endAttribute, $lastStmt->getAttribute($endAttribute));
            }
        }
    }

    /** @return array<string, mixed> */
    private function getNamespaceErrorAttributes(Namespace_ $node): array {
        $attrs = $node->getAttributes();
        // Adjust end attributes to only cover the "namespace" keyword, not the whole namespace.
        if (isset($attrs['startLine'])) {
            $attrs['endLine'] = $attrs['startLine'];
        }
        if (isset($attrs['startTokenPos'])) {
            $attrs['endTokenPos'] = $attrs['startTokenPos'];
        }
        if (isset($attrs['startFilePos'])) {
            $attrs['endFilePos'] = $attrs['startFilePos'] + \strlen('namespace') - 1;
        }
        return $attrs;
    }

    /**
     * Determine namespacing style (semicolon or brace)
     *
     * @param Node[] $stmts Top-level statements.
     *
     * @return null|string One of "semicolon", "brace" or null (no namespaces)
     */
    private function getNamespacingStyle(array $stmts): ?string {
        $style = null;
        $hasNotAllowedStmts = false;
        foreach ($stmts as $i => $stmt) {
            if ($stmt instanceof Node\Stmt\Namespace_) {
                $currentStyle = null === $stmt->stmts ? 'semicolon' : 'brace';
                if (null === $style) {
                    $style = $currentStyle;
                    if ($hasNotAllowedStmts) {
                        $this->emitError(new Error(
                            'Namespace declaration statement has to be the very first statement in the script',
                            $this->getNamespaceErrorAttributes($stmt)
                        ));
                    }
                } elseif ($style !== $currentStyle) {
                    $this->emitError(new Error(
                        'Cannot mix bracketed namespace declarations with unbracketed namespace declarations',
                        $this->getNamespaceErrorAttributes($stmt)
                    ));
                    // Treat like semicolon style for namespace normalization
                    return 'semicolon';
                }
                continue;
            }

            /* declare(), __halt_compiler() and nops can be used before a namespace declaration */
            if ($stmt instanceof Node\Stmt\Declare_
                || $stmt instanceof Node\Stmt\HaltCompiler
                || $stmt instanceof Node\Stmt\Nop) {
                continue;
            }

            /* There may be a hashbang line at the very start of the file */
            if ($i === 0 && $stmt instanceof Node\Stmt\InlineHTML && preg_match('/\A#!.*\r?\n\z/', $stmt->value)) {
                continue;
            }

            /* Everything else if forbidden before namespace declarations */
            $hasNotAllowedStmts = true;
        }
        return $style;
    }

    /** @return Name|Identifier */
    protected function handleBuiltinTypes(Name $name) {
        if (!$name->isUnqualified()) {
            return $name;
        }

        $lowerName = $name->toLowerString();
        if (!$this->phpVersion->supportsBuiltinType($lowerName)) {
            return $name;
        }

        return new Node\Identifier($lowerName, $name->getAttributes());
    }

    /**
     * Get combined start and end attributes at a stack location
     *
     * @param int $stackPos Stack location
     *
     * @return array<string, mixed> Combined start and end attributes
     */
    protected function getAttributesAt(int $stackPos): array {
        return $this->getAttributes($this->tokenStartStack[$stackPos], $this->tokenEndStack[$stackPos]);
    }

    protected function getFloatCastKind(string $cast): int {
        $cast = strtolower($cast);
        if (strpos($cast, 'float') !== false) {
            return Double::KIND_FLOAT;
        }

        if (strpos($cast, 'real') !== false) {
            return Double::KIND_REAL;
        }

        return Double::KIND_DOUBLE;
    }

    /** @param array<string, mixed> $attributes */
    protected function parseLNumber(string $str, array $attributes, bool $allowInvalidOctal = false): Int_ {
        try {
            return Int_::fromString($str, $attributes, $allowInvalidOctal);
        } catch (Error $error) {
            $this->emitError($error);
            // Use dummy value
            return new Int_(0, $attributes);
        }
    }

    /**
     * Parse a T_NUM_STRING token into either an integer or string node.
     *
     * @param string $str Number string
     * @param array<string, mixed> $attributes Attributes
     *
     * @return Int_|String_ Integer or string node.
     */
    protected function parseNumString(string $str, array $attributes) {
        if (!preg_match('/^(?:0|-?[1-9][0-9]*)$/', $str)) {
            return new String_($str, $attributes);
        }

        $num = +$str;
        if (!is_int($num)) {
            return new String_($str, $attributes);
        }

        return new Int_($num, $attributes);
    }

    /** @param array<string, mixed> $attributes */
    protected function stripIndentation(
        string $string, int $indentLen, string $indentChar,
        bool $newlineAtStart, bool $newlineAtEnd, array $attributes
    ): string {
        if ($indentLen === 0) {
            return $string;
        }

        $start = $newlineAtStart ? '(?:(?<=\n)|\A)' : '(?<=\n)';
        $end = $newlineAtEnd ? '(?:(?=[\r\n])|\z)' : '(?=[\r\n])';
        $regex = '/' . $start . '([ \t]*)(' . $end . ')?/';
        return preg_replace_callback(
            $regex,
            function ($matches) use ($indentLen, $indentChar, $attributes) {
                $prefix = substr($matches[1], 0, $indentLen);
                if (false !== strpos($prefix, $indentChar === " " ? "\t" : " ")) {
                    $this->emitError(new Error(
                        'Invalid indentation - tabs and spaces cannot be mixed', $attributes
                    ));
                } elseif (strlen($prefix) < $indentLen && !isset($matches[2])) {
                    $this->emitError(new Error(
                        'Invalid body indentation level ' .
                        '(expecting an indentation level of at least ' . $indentLen . ')',
                        $attributes
                    ));
                }
                return substr($matches[0], strlen($prefix));
            },
            $string
        );
    }

    /**
     * @param string|(Expr|InterpolatedStringPart)[] $contents
     * @param array<string, mixed> $attributes
     * @param array<string, mixed> $endTokenAttributes
     */
    protected function parseDocString(
        string $startToken, $contents, string $endToken,
        array $attributes, array $endTokenAttributes, bool $parseUnicodeEscape
    ): Expr {
        $kind = strpos($startToken, "'") === false
            ? String_::KIND_HEREDOC : String_::KIND_NOWDOC;

        $regex = '/\A[bB]?<<<[ \t]*[\'"]?([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)[\'"]?(?:\r\n|\n|\r)\z/';
        $result = preg_match($regex, $startToken, $matches);
        assert($result === 1);
        $label = $matches[1];

        $result = preg_match('/\A[ \t]*/', $endToken, $matches);
        assert($result === 1);
        $indentation = $matches[0];

        $attributes['kind'] = $kind;
        $attributes['docLabel'] = $label;
        $attributes['docIndentation'] = $indentation;

        $indentHasSpaces = false !== strpos($indentation, " ");
        $indentHasTabs = false !== strpos($indentation, "\t");
        if ($indentHasSpaces && $indentHasTabs) {
            $this->emitError(new Error(
                'Invalid indentation - tabs and spaces cannot be mixed',
                $endTokenAttributes
            ));

            // Proceed processing as if this doc string is not indented
            $indentation = '';
        }

        $indentLen = \strlen($indentation);
        $indentChar = $indentHasSpaces ? " " : "\t";

        if (\is_string($contents)) {
            if ($contents === '') {
                $attributes['rawValue'] = $contents;
                return new String_('', $attributes);
            }

            $contents = $this->stripIndentation(
                $contents, $indentLen, $indentChar, true, true, $attributes
            );
            $contents = preg_replace('~(\r\n|\n|\r)\z~', '', $contents);
            $attributes['rawValue'] = $contents;

            if ($kind === String_::KIND_HEREDOC) {
                $contents = String_::parseEscapeSequences($contents, null, $parseUnicodeEscape);
            }

            return new String_($contents, $attributes);
        } else {
            assert(count($contents) > 0);
            if (!$contents[0] instanceof Node\InterpolatedStringPart) {
                // If there is no leading encapsed string part, pretend there is an empty one
                $this->stripIndentation(
                    '', $indentLen, $indentChar, true, false, $contents[0]->getAttributes()
                );
            }

            $newContents = [];
            foreach ($contents as $i => $part) {
                if ($part instanceof Node\InterpolatedStringPart) {
                    $isLast = $i === \count($contents) - 1;
                    $part->value = $this->stripIndentation(
                        $part->value, $indentLen, $indentChar,
                        $i === 0, $isLast, $part->getAttributes()
                    );
                    if ($isLast) {
                        $part->value = preg_replace('~(\r\n|\n|\r)\z~', '', $part->value);
                    }
                    $part->setAttribute('rawValue', $part->value);
                    $part->value = String_::parseEscapeSequences($part->value, null, $parseUnicodeEscape);
                    if ('' === $part->value) {
                        continue;
                    }
                }
                $newContents[] = $part;
            }
            return new InterpolatedString($newContents, $attributes);
        }
    }

    protected function createCommentFromToken(Token $token, int $tokenPos): Comment {
        assert($token->id === \T_COMMENT || $token->id == \T_DOC_COMMENT);
        return \T_DOC_COMMENT === $token->id
            ? new Comment\Doc($token->text, $token->line, $token->pos, $tokenPos,
                $token->getEndLine(), $token->getEndPos() - 1, $tokenPos)
            : new Comment($token->text, $token->line, $token->pos, $tokenPos,
                $token->getEndLine(), $token->getEndPos() - 1, $tokenPos);
    }

    /**
     * Get last comment before the given token position, if any
     */
    protected function getCommentBeforeToken(int $tokenPos): ?Comment {
        while (--$tokenPos >= 0) {
            $token = $this->tokens[$tokenPos];
            if (!isset($this->dropTokens[$token->id])) {
                break;
            }

            if ($token->id === \T_COMMENT || $token->id === \T_DOC_COMMENT) {
                return $this->createCommentFromToken($token, $tokenPos);
            }
        }
        return null;
    }

    /**
     * Create a zero-length nop to capture preceding comments, if any.
     */
    protected function maybeCreateZeroLengthNop(int $tokenPos): ?Nop {
        $comment = $this->getCommentBeforeToken($tokenPos);
        if ($comment === null) {
            return null;
        }

        $commentEndLine = $comment->getEndLine();
        $commentEndFilePos = $comment->getEndFilePos();
        $commentEndTokenPos = $comment->getEndTokenPos();
        $attributes = [
            'startLine' => $commentEndLine,
            'endLine' => $commentEndLine,
            'startFilePos' => $commentEndFilePos + 1,
            'endFilePos' => $commentEndFilePos,
            'startTokenPos' => $commentEndTokenPos + 1,
            'endTokenPos' => $commentEndTokenPos,
        ];
        return new Nop($attributes);
    }

    protected function maybeCreateNop(int $tokenStartPos, int $tokenEndPos): ?Nop {
        if ($this->getCommentBeforeToken($tokenStartPos) === null) {
            return null;
        }
        return new Nop($this->getAttributes($tokenStartPos, $tokenEndPos));
    }

    protected function handleHaltCompiler(): string {
        // Prevent the lexer from returning any further tokens.
        $nextToken = $this->tokens[$this->tokenPos + 1];
        $this->tokenPos = \count($this->tokens) - 2;

        // Return text after __halt_compiler.
        return $nextToken->id === \T_INLINE_HTML ? $nextToken->text : '';
    }

    protected function inlineHtmlHasLeadingNewline(int $stackPos): bool {
        $tokenPos = $this->tokenStartStack[$stackPos];
        $token = $this->tokens[$tokenPos];
        assert($token->id == \T_INLINE_HTML);
        if ($tokenPos > 0) {
            $prevToken = $this->tokens[$tokenPos - 1];
            assert($prevToken->id == \T_CLOSE_TAG);
            return false !== strpos($prevToken->text, "\n")
                || false !== strpos($prevToken->text, "\r");
        }
        return true;
    }

    /**
     * @return array<string, mixed>
     */
    protected function createEmptyElemAttributes(int $tokenPos): array {
        return $this->getAttributesForToken($tokenPos);
    }

    protected function fixupArrayDestructuring(Array_ $node): Expr\List_ {
        $this->createdArrays->detach($node);
        return new Expr\List_(array_map(function (Node\ArrayItem $item) {
            if ($item->value instanceof Expr\Error) {
                // We used Error as a placeholder for empty elements, which are legal for destructuring.
                return null;
            }
            if ($item->value instanceof Array_) {
                return new Node\ArrayItem(
                    $this->fixupArrayDestructuring($item->value),
                    $item->key, $item->byRef, $item->getAttributes());
            }
            return $item;
        }, $node->items), ['kind' => Expr\List_::KIND_ARRAY] + $node->getAttributes());
    }

    protected function postprocessList(Expr\List_ $node): void {
        foreach ($node->items as $i => $item) {
            if ($item->value instanceof Expr\Error) {
                // We used Error as a placeholder for empty elements, which are legal for destructuring.
                $node->items[$i] = null;
            }
        }
    }

    /** @param ElseIf_|Else_ $node */
    protected function fixupAlternativeElse($node): void {
        // Make sure a trailing nop statement carrying comments is part of the node.
        $numStmts = \count($node->stmts);
        if ($numStmts !== 0 && $node->stmts[$numStmts - 1] instanceof Nop) {
            $nopAttrs = $node->stmts[$numStmts - 1]->getAttributes();
            if (isset($nopAttrs['endLine'])) {
                $node->setAttribute('endLine', $nopAttrs['endLine']);
            }
            if (isset($nopAttrs['endFilePos'])) {
                $node->setAttribute('endFilePos', $nopAttrs['endFilePos']);
            }
            if (isset($nopAttrs['endTokenPos'])) {
                $node->setAttribute('endTokenPos', $nopAttrs['endTokenPos']);
            }
        }
    }

    protected function checkClassModifier(int $a, int $b, int $modifierPos): void {
        try {
            Modifiers::verifyClassModifier($a, $b);
        } catch (Error $error) {
            $error->setAttributes($this->getAttributesAt($modifierPos));
            $this->emitError($error);
        }
    }

    protected function checkModifier(int $a, int $b, int $modifierPos): void {
        // Jumping through some hoops here because verifyModifier() is also used elsewhere
        try {
            Modifiers::verifyModifier($a, $b);
        } catch (Error $error) {
            $error->setAttributes($this->getAttributesAt($modifierPos));
            $this->emitError($error);
        }
    }

    protected function checkParam(Param $node): void {
        if ($node->variadic && null !== $node->default) {
            $this->emitError(new Error(
                'Variadic parameter cannot have a default value',
                $node->default->getAttributes()
            ));
        }
    }

    protected function checkTryCatch(TryCatch $node): void {
        if (empty($node->catches) && null === $node->finally) {
            $this->emitError(new Error(
                'Cannot use try without catch or finally', $node->getAttributes()
            ));
        }
    }

    protected function checkNamespace(Namespace_ $node): void {
        if (null !== $node->stmts) {
            foreach ($node->stmts as $stmt) {
                if ($stmt instanceof Namespace_) {
                    $this->emitError(new Error(
                        'Namespace declarations cannot be nested', $stmt->getAttributes()
                    ));
                }
            }
        }
    }

    private function checkClassName(?Identifier $name, int $namePos): void {
        if (null !== $name && $name->isSpecialClassName()) {
            $this->emitError(new Error(
                sprintf('Cannot use \'%s\' as class name as it is reserved', $name),
                $this->getAttributesAt($namePos)
            ));
        }
    }

    /** @param Name[] $interfaces */
    private function checkImplementedInterfaces(array $interfaces): void {
        foreach ($interfaces as $interface) {
            if ($interface->isSpecialClassName()) {
                $this->emitError(new Error(
                    sprintf('Cannot use \'%s\' as interface name as it is reserved', $interface),
                    $interface->getAttributes()
                ));
            }
        }
    }

    protected function checkClass(Class_ $node, int $namePos): void {
        $this->checkClassName($node->name, $namePos);

        if ($node->extends && $node->extends->isSpecialClassName()) {
            $this->emitError(new Error(
                sprintf('Cannot use \'%s\' as class name as it is reserved', $node->extends),
                $node->extends->getAttributes()
            ));
        }

        $this->checkImplementedInterfaces($node->implements);
    }

    protected function checkInterface(Interface_ $node, int $namePos): void {
        $this->checkClassName($node->name, $namePos);
        $this->checkImplementedInterfaces($node->extends);
    }

    protected function checkEnum(Enum_ $node, int $namePos): void {
        $this->checkClassName($node->name, $namePos);
        $this->checkImplementedInterfaces($node->implements);
    }

    protected function checkClassMethod(ClassMethod $node, int $modifierPos): void {
        if ($node->flags & Modifiers::STATIC) {
            switch ($node->name->toLowerString()) {
                case '__construct':
                    $this->emitError(new Error(
                        sprintf('Constructor %s() cannot be static', $node->name),
                        $this->getAttributesAt($modifierPos)));
                    break;
                case '__destruct':
                    $this->emitError(new Error(
                        sprintf('Destructor %s() cannot be static', $node->name),
                        $this->getAttributesAt($modifierPos)));
                    break;
                case '__clone':
                    $this->emitError(new Error(
                        sprintf('Clone method %s() cannot be static', $node->name),
                        $this->getAttributesAt($modifierPos)));
                    break;
            }
        }

        if ($node->flags & Modifiers::READONLY) {
            $this->emitError(new Error(
                sprintf('Method %s() cannot be readonly', $node->name),
                $this->getAttributesAt($modifierPos)));
        }
    }

    protected function checkClassConst(ClassConst $node, int $modifierPos): void {
        if ($node->flags & Modifiers::STATIC) {
            $this->emitError(new Error(
                "Cannot use 'static' as constant modifier",
                $this->getAttributesAt($modifierPos)));
        }
        if ($node->flags & Modifiers::ABSTRACT) {
            $this->emitError(new Error(
                "Cannot use 'abstract' as constant modifier",
                $this->getAttributesAt($modifierPos)));
        }
        if ($node->flags & Modifiers::READONLY) {
            $this->emitError(new Error(
                "Cannot use 'readonly' as constant modifier",
                $this->getAttributesAt($modifierPos)));
        }
    }

    protected function checkProperty(Property $node, int $modifierPos): void {
        if ($node->flags & Modifiers::ABSTRACT) {
            $this->emitError(new Error('Properties cannot be declared abstract',
                $this->getAttributesAt($modifierPos)));
        }

        if ($node->flags & Modifiers::FINAL) {
            $this->emitError(new Error('Properties cannot be declared final',
                $this->getAttributesAt($modifierPos)));
        }
    }

    protected function checkUseUse(UseItem $node, int $namePos): void {
        if ($node->alias && $node->alias->isSpecialClassName()) {
            $this->emitError(new Error(
                sprintf(
                    'Cannot use %s as %s because \'%2$s\' is a special class name',
                    $node->name, $node->alias
                ),
                $this->getAttributesAt($namePos)
            ));
        }
    }

    /**
     * Creates the token map.
     *
     * The token map maps the PHP internal token identifiers
     * to the identifiers used by the Parser. Additionally it
     * maps T_OPEN_TAG_WITH_ECHO to T_ECHO and T_CLOSE_TAG to ';'.
     *
     * @return array<int, int> The token map
     */
    protected function createTokenMap(): array {
        $tokenMap = [];

        for ($i = 0; $i < 1000; ++$i) {
            if ($i < 256) {
                // Single-char tokens use an identity mapping.
                $tokenMap[$i] = $i;
            } elseif (\T_DOUBLE_COLON === $i) {
                // T_DOUBLE_COLON is equivalent to T_PAAMAYIM_NEKUDOTAYIM
                $tokenMap[$i] = static::T_PAAMAYIM_NEKUDOTAYIM;
            } elseif (\T_OPEN_TAG_WITH_ECHO === $i) {
                // T_OPEN_TAG_WITH_ECHO with dropped T_OPEN_TAG results in T_ECHO
                $tokenMap[$i] = static::T_ECHO;
            } elseif (\T_CLOSE_TAG === $i) {
                // T_CLOSE_TAG is equivalent to ';'
                $tokenMap[$i] = ord(';');
            } elseif ('UNKNOWN' !== $name = token_name($i)) {
                if (defined($name = static::class . '::' . $name)) {
                    // Other tokens can be mapped directly
                    $tokenMap[$i] = constant($name);
                }
            }
        }

        // Assign tokens for which we define compatibility constants, as token_name() does not know them.
        $tokenMap[\T_FN] = static::T_FN;
        $tokenMap[\T_COALESCE_EQUAL] = static::T_COALESCE_EQUAL;
        $tokenMap[\T_NAME_QUALIFIED] = static::T_NAME_QUALIFIED;
        $tokenMap[\T_NAME_FULLY_QUALIFIED] = static::T_NAME_FULLY_QUALIFIED;
        $tokenMap[\T_NAME_RELATIVE] = static::T_NAME_RELATIVE;
        $tokenMap[\T_MATCH] = static::T_MATCH;
        $tokenMap[\T_NULLSAFE_OBJECT_OPERATOR] = static::T_NULLSAFE_OBJECT_OPERATOR;
        $tokenMap[\T_ATTRIBUTE] = static::T_ATTRIBUTE;
        $tokenMap[\T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG] = static::T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG;
        $tokenMap[\T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG] = static::T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG;
        $tokenMap[\T_ENUM] = static::T_ENUM;
        $tokenMap[\T_READONLY] = static::T_READONLY;

        // We have create a map from PHP token IDs to external symbol IDs.
        // Now map them to the internal symbol ID.
        $fullTokenMap = [];
        foreach ($tokenMap as $phpToken => $extSymbol) {
            $intSymbol = $this->tokenToSymbol[$extSymbol];
            if ($intSymbol === $this->invalidSymbol) {
                continue;
            }
            $fullTokenMap[$phpToken] = $intSymbol;
        }

        return $fullTokenMap;
    }
}

.NET Framework

Project Request

ProjectC

Vehicle Maintenance

Movie Navigator

Customers Exchange

ATM

.NET Core

Mail Daemon

Custom

Buns of code

PHP

Mediabox

Loan Castle

Content Management

Laravel

Phone Check

Frontend

Forex Wall

Business projects

Certification Center

Amerikas Auto

Pet projects

Geolocation Assistant

Web Dynamics

Blackball

Good old times

DOS Clock

BrainOut

Airport Administrator

Atomizer

Mediabox