Parser::previewToken() - Code Metrics - remorhaz/php-unilex - Measure and Improve Code Quality continuously with Scrutinizer

Parser::previewToken() A
last analyzed 2023-06-12 18:01 UTC

↳ Parent: Parser

Complexity

Conditions	2
Paths	2

Size

Total Lines	6
Code Lines	3

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	2
eloc	3
c	0
b	0
f	0
nc	2
nop	0
dl	0
loc	6
rs	10

<?php

declare(strict_types=1);

namespace Remorhaz\UniLex\Parser\LL1;

use Remorhaz\UniLex\Exception;
use Remorhaz\UniLex\Grammar\ContextFree\GrammarInterface;
use Remorhaz\UniLex\Parser\LL1\Lookup\Table;
use Remorhaz\UniLex\Parser\Production;
use Remorhaz\UniLex\Parser\Symbol;
use Remorhaz\UniLex\Stack\SymbolStack;
use Remorhaz\UniLex\Stack\StackableSymbolInterface;
use Remorhaz\UniLex\Lexer\Token;
use Remorhaz\UniLex\Lexer\TokenReaderInterface;
use Remorhaz\UniLex\Parser\LL1\Lookup\TableInterface;
use Remorhaz\UniLex\Parser\LL1\Lookup\TableBuilder;
use Throwable;

class Parser
{
    private $grammar;

    private $lookupTable;

    private $symbolStack;

    private $token;

    private $tokenReader;

    private $listener;

    private $nextSymbolIndex = 0;

    /**
     * @var Production[]
     */
    private $productionMap = [];

    public function __construct(
        GrammarInterface $grammar,
        TokenReaderInterface $tokenReader,
        ParserListenerInterface $listener
    ) {
        $this->grammar = $grammar;
        $this->tokenReader = $tokenReader;
        $this->listener = $listener;
        $this->symbolStack = new SymbolStack();
    }

    /**
     * @param string $fileName
     * @throws Exception
     */
    public function loadLookupTable(string $fileName): void
    {
        /** @noinspection PhpIncludeInspection */
        $data = @include $fileName;
        if (false === $data) {
            throw new Exception("Failed to load lookup table from file {$fileName}");
        }
        $table = new Table();
        $table->importMap($data);
        $this->lookupTable = $table;
    }

    /**
     * @throws Exception
     * @throws UnexpectedTokenException
     */
    public function run(): void
    {
        $this->initRun();
        while ($this->hasSymbolInStack()) {
            $symbol = $this->popSymbol();
            if ($symbol instanceof Symbol) {
                $this->isTerminalSymbol($symbol)
                    ? $this->readSymbolToken($symbol)
                    : $this->pushMatchingProduction($symbol);
                continue;
            }
            if ($symbol instanceof Production) {
                $this->listener->onFinishProduction($symbol);
            }
        }
    }

    private function initRun(): void
    {
        $this->nextSymbolIndex = 0;
        $this->productionMap = [];
        $this->symbolStack->reset();
        $this->listener->onStart();
        $this->pushProduction($this->createRootProduction());
    }

    private function createRootProduction(): Production
    {
        $rootSymbol = new Symbol($this->getNextSymbolIndex(), $this->grammar->getRootSymbol());
        $this->listener->onRootSymbol($rootSymbol);
        return $this->createParsedProduction($rootSymbol, 0);
    }

    private function getNextSymbolIndex(): int
    {
        return $this->nextSymbolIndex++;
    }

    private function hasSymbolInStack(): bool
    {
        return !$this->symbolStack->isEmpty();
    }

    private function isTerminalSymbol(Symbol $symbol): bool
    {
        return $this->grammar->isTerminal($symbol->getSymbolId());
    }

    private function previewToken(): Token
    {
        if (!isset($this->token)) {
            $this->token = $this->tokenReader->read();
        }
        return $this->token;
    }

    /**
     * @return StackableSymbolInterface
     * @throws Exception
     */
    private function popSymbol(): StackableSymbolInterface
    {
        return $this->symbolStack->pop();
    }

    /**
     * @param Symbol $symbol
     * @throws Exception
     */
    private function onSymbol(Symbol $symbol): void
    {
        if (!isset($this->productionMap[$symbol->getIndex()])) {
            throw new Exception("No production in map for symbol {$symbol->getIndex()}");
        }
        [$symbolIndex, $production] = $this->productionMap[$symbol->getIndex()];
        $this->listener->onSymbol($symbolIndex, $production);
    }

    /**
     * @param Symbol $symbol
     * @throws Exception
     */
    private function readSymbolToken(Symbol $symbol): void
    {
        $token = $this->previewToken();
        if (!$this->grammar->tokenMatchesTerminal($symbol->getSymbolId(), $token->getType())) {
            throw new Exception("Unexpected token {$token->getType()} for symbol {$symbol->getSymbolId()}");
        }
        $token->isEoi()
            ? $this->listener->onEoi($symbol, $token)
            : $this->listener->onToken($symbol, $token);
        $this->onSymbol($symbol);
        unset($this->token);
    }

    /**
     * @param Symbol $symbol
     * @throws UnexpectedTokenException
     * @throws Exception
     */
    private function pushMatchingProduction(Symbol $symbol): void
    {
        $this->onSymbol($symbol);
        $production = $this->getMatchingProduction($symbol, $this->previewToken());
        $this->pushProduction($production);
    }

    private function pushProduction(Production $production): void
    {
        $this->symbolStack->push($production);
        foreach ($production->getSymbolList() as $symbolIndexInProduction => $symbol) {
            $this->productionMap[$symbol->getIndex()] = [$symbolIndexInProduction, $production];
        }
        $this->symbolStack->push(...$production->getSymbolList());
        $this->listener->onBeginProduction($production);
    }

    /**
     * @param Symbol $symbol
     * @param Token $token
     * @return Production
     * @throws UnexpectedTokenException
     * @throws Exception
     */
    private function getMatchingProduction(Symbol $symbol, Token $token): Production
    {
        $lookupTable = $this->getLookupTable();
        try {
            $productionIndex = $lookupTable->getProductionIndex($symbol->getSymbolId(), $token->getType());
        } catch (Throwable $e) {
            $expectedTokenList = $lookupTable->getExpectedTokenList($symbol->getSymbolId());
            $error = new UnexpectedTokenError($token, $symbol, ...$expectedTokenList);
            throw new UnexpectedTokenException($error, 0, $e);
        }
        return $this->createParsedProduction($symbol, $productionIndex);
    }

    private function createParsedProduction(Symbol $symbol, $productionIndex): Production
    {
        $grammarProduction = $this
            ->grammar
            ->getProduction($symbol->getSymbolId(), $productionIndex);
        $symbolList = [];
        foreach ($grammarProduction->getSymbolList() as $symbolId) {
            $symbolList[] = new Symbol($this->getNextSymbolIndex(), $symbolId);
        }
        return new Production($symbol, $grammarProduction->getIndex(), ...$symbolList);
    }

    /**
     * @return TableInterface
     * @throws Exception
     */
    private function getLookupTable(): TableInterface
    {
        if (!isset($this->lookupTable)) {
            $builder = new TableBuilder($this->grammar);
            $this->lookupTable = $builder->getTable();
        }
        return $this->lookupTable;
    }
}


1			<?php
2
3			declare(strict_types=1);
4
5			namespace Remorhaz\UniLex\Parser\LL1;
6
7			use Remorhaz\UniLex\Exception;
8			use Remorhaz\UniLex\Grammar\ContextFree\GrammarInterface;
9			use Remorhaz\UniLex\Parser\LL1\Lookup\Table;
10			use Remorhaz\UniLex\Parser\Production;
11			use Remorhaz\UniLex\Parser\Symbol;
12			use Remorhaz\UniLex\Stack\SymbolStack;
13			use Remorhaz\UniLex\Stack\StackableSymbolInterface;
14			use Remorhaz\UniLex\Lexer\Token;
15			use Remorhaz\UniLex\Lexer\TokenReaderInterface;
16			use Remorhaz\UniLex\Parser\LL1\Lookup\TableInterface;
17			use Remorhaz\UniLex\Parser\LL1\Lookup\TableBuilder;
18			use Throwable;
19
20			class Parser
21			{
22			private $grammar;
23
24			private $lookupTable;
25
26			private $symbolStack;
27
28			private $token;
29
30			private $tokenReader;
31
32			private $listener;
33
34			private $nextSymbolIndex = 0;
35
36			/**
37			* @var Production[]
38			*/
39			private $productionMap = [];
40
41			public function __construct(
42			GrammarInterface $grammar,
43			TokenReaderInterface $tokenReader,
44			ParserListenerInterface $listener
45			) {
46			$this->grammar = $grammar;
47			$this->tokenReader = $tokenReader;
48			$this->listener = $listener;
49			$this->symbolStack = new SymbolStack();
50			}
51
52			/**
53			* @param string $fileName
54			* @throws Exception
55			*/
56			public function loadLookupTable(string $fileName): void
57			{
58			/** @noinspection PhpIncludeInspection */
59			$data = @include $fileName;
60			if (false === $data) {
61			throw new Exception("Failed to load lookup table from file {$fileName}");
62			}
63			$table = new Table();
64			$table->importMap($data);
65			$this->lookupTable = $table;
66			}
67
68			/**
69			* @throws Exception
70			* @throws UnexpectedTokenException
71			*/
72			public function run(): void
73			{
74			$this->initRun();
75			while ($this->hasSymbolInStack()) {
76			$symbol = $this->popSymbol();
77			if ($symbol instanceof Symbol) {
78			$this->isTerminalSymbol($symbol)
79			? $this->readSymbolToken($symbol)
80			: $this->pushMatchingProduction($symbol);
81			continue;
82			}
83			if ($symbol instanceof Production) {
84			$this->listener->onFinishProduction($symbol);
85			}
86			}
87			}
88
89			private function initRun(): void
90			{
91			$this->nextSymbolIndex = 0;
92			$this->productionMap = [];
93			$this->symbolStack->reset();
94			$this->listener->onStart();
95			$this->pushProduction($this->createRootProduction());
96			}
97
98			private function createRootProduction(): Production
99			{
100			$rootSymbol = new Symbol($this->getNextSymbolIndex(), $this->grammar->getRootSymbol());
101			$this->listener->onRootSymbol($rootSymbol);
102			return $this->createParsedProduction($rootSymbol, 0);
103			}
104
105			private function getNextSymbolIndex(): int
106			{
107			return $this->nextSymbolIndex++;
108			}
109
110			private function hasSymbolInStack(): bool
111			{
112			return !$this->symbolStack->isEmpty();
113			}
114
115			private function isTerminalSymbol(Symbol $symbol): bool
116			{
117			return $this->grammar->isTerminal($symbol->getSymbolId());
118			}
119
120			private function previewToken(): Token
121			{
122			if (!isset($this->token)) {
123			$this->token = $this->tokenReader->read();
124			}
125			return $this->token;
126			}
127
128			/**
129			* @return StackableSymbolInterface
130			* @throws Exception
131			*/
132			private function popSymbol(): StackableSymbolInterface
133			{
134			return $this->symbolStack->pop();
135			}
136
137			/**
138			* @param Symbol $symbol
139			* @throws Exception
140			*/
141			private function onSymbol(Symbol $symbol): void
142			{
143			if (!isset($this->productionMap[$symbol->getIndex()])) {
144			throw new Exception("No production in map for symbol {$symbol->getIndex()}");
145			}
146			[$symbolIndex, $production] = $this->productionMap[$symbol->getIndex()];
147			$this->listener->onSymbol($symbolIndex, $production);
148			}
149
150			/**
151			* @param Symbol $symbol
152			* @throws Exception
153			*/
154			private function readSymbolToken(Symbol $symbol): void
155			{
156			$token = $this->previewToken();
157			if (!$this->grammar->tokenMatchesTerminal($symbol->getSymbolId(), $token->getType())) {
158			throw new Exception("Unexpected token {$token->getType()} for symbol {$symbol->getSymbolId()}");
159			}
160			$token->isEoi()
161			? $this->listener->onEoi($symbol, $token)
162			: $this->listener->onToken($symbol, $token);
163			$this->onSymbol($symbol);
164			unset($this->token);
165			}
166
167			/**
168			* @param Symbol $symbol
169			* @throws UnexpectedTokenException
170			* @throws Exception
171			*/
172			private function pushMatchingProduction(Symbol $symbol): void
173			{
174			$this->onSymbol($symbol);
175			$production = $this->getMatchingProduction($symbol, $this->previewToken());
176			$this->pushProduction($production);
177			}
178
179			private function pushProduction(Production $production): void
180			{
181			$this->symbolStack->push($production);
182			foreach ($production->getSymbolList() as $symbolIndexInProduction => $symbol) {
183			$this->productionMap[$symbol->getIndex()] = [$symbolIndexInProduction, $production];
184			}
185			$this->symbolStack->push(...$production->getSymbolList());
186			$this->listener->onBeginProduction($production);
187			}
188
189			/**
190			* @param Symbol $symbol
191			* @param Token $token
192			* @return Production
193			* @throws UnexpectedTokenException
194			* @throws Exception
195			*/
196			private function getMatchingProduction(Symbol $symbol, Token $token): Production
197			{
198			$lookupTable = $this->getLookupTable();
199			try {
200			$productionIndex = $lookupTable->getProductionIndex($symbol->getSymbolId(), $token->getType());
201			} catch (Throwable $e) {
202			$expectedTokenList = $lookupTable->getExpectedTokenList($symbol->getSymbolId());
203			$error = new UnexpectedTokenError($token, $symbol, ...$expectedTokenList);
204			throw new UnexpectedTokenException($error, 0, $e);
205			}
206			return $this->createParsedProduction($symbol, $productionIndex);
207			}
208
209			private function createParsedProduction(Symbol $symbol, $productionIndex): Production
210			{
211			$grammarProduction = $this
212			->grammar
213			->getProduction($symbol->getSymbolId(), $productionIndex);
214			$symbolList = [];
215			foreach ($grammarProduction->getSymbolList() as $symbolId) {
216			$symbolList[] = new Symbol($this->getNextSymbolIndex(), $symbolId);
217			}
218			return new Production($symbol, $grammarProduction->getIndex(), ...$symbolList);
219			}
220
221			/**
222			* @return TableInterface
223			* @throws Exception
224			*/
225			private function getLookupTable(): TableInterface
226			{
227			if (!isset($this->lookupTable)) {
228			$builder = new TableBuilder($this->grammar);
229			$this->lookupTable = $builder->getTable();
230			}
231			return $this->lookupTable;
232			}
233			}
234

remorhaz / php-unilex

Parser::previewToken() A last analyzed 2023-06-12 18:01 UTC

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Parser::previewToken() A
last analyzed 2023-06-12 18:01 UTC