Lexer - Code Metrics - Inspection of "Merge pull request #1 from hansott/feature-schema-..." - hansott/graphql-language - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( b0b79e...9ac4d8 )

by Hans

created 2017-09-23 18:45 UTC

Lexer C

↳ Parent: Project

Complexity

Total Complexity

Size/Duplication

Total Lines	266
Duplicated Lines	65.79 %

Coupling/Cohesion

Components	1
Dependencies	5

Test Coverage

Coverage

54.44%

Importance

Changes

Metric	Value
wmc	58
lcom	1
cbo	5
dl	175
loc	266
ccs	92
cts	169
cp	0.5444
rs	6.3005
c	0
b	0
f	0

11 Methods

Rating	Name	Duplication	Size	Complexity
A	emit()	0	4	1
A	getLocation()	0	7	1
A	getError()	0	7	1
D	name()	7	30	9
A	comment()	9	9	4
B	str()	23	23	5
C	integerPart()	28	28	7
B	fractionalPart()	21	21	5
C	exponentPart()	26	26	7
C	number()	26	26	8
C	lex()	35	59	10

How to fix Duplicated Code Complexity

Duplicated Code

Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.

Common duplication problems, and corresponding solutions are:

If you have the same expression in different places: Extract expression to a method
If you have the same method in different sub-classes: Extract method, and pull up field to the parent class
If you have the same code in unrelated classes: Consider extracting the code to a new class, and injecting that class

Complex Class

Tip: Before tackling complexity, make sure that you eliminate any duplication first. This often can reduce the size of classes significantly.

Complex classes like Lexer often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.

Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.

While breaking up the class, it is a good idea to analyze how other classes use Lexer, and based on these observations, apply Extract Interface, too.

<?php

namespace HansOtt\GraphQL\Schema;

use HansOtt\GraphQL\Shared\ScannerGeneric;
use HansOtt\GraphQL\Shared\ScannerWithLocation;
use HansOtt\GraphQL\Shared\Lexer as LexerShared;

final class Lexer implements LexerShared
{
    /**
     * @var ScannerWithLocation
     */
    private $scanner;
    private $tokens;

    private function emit($type, $value, $location)
    {
        $this->tokens[] = new Token($type, $value, $location);
    }

    private function getLocation()
    {
        $line = $this->scanner->getLine();
        $column = $this->scanner->getColumn();

        return new Location($line, $column);
    }

    private function getError($message)
    {
        $line = $this->scanner->getLine();
        $column = $this->scanner->getColumn();

        return new SyntaxError($message . " (line {$line}, column {$column})");
    }

    private function name()
    {
        $name = $this->scanner->next();
        $location = $this->getLocation();

        if ($this->scanner->eof()) {
            $this->emit(Token::T_NAME, $name, $location);
            return;
        }

        $next = $this->scanner->peek();
        while ($next === '_' || ctype_alpha($next) || ctype_digit($next)) {

            $name .= $this->scanner->next();
            if ($this->scanner->eof()) {
                break;
            }
            $next = $this->scanner->peek();
        }

        $type = Token::T_NAME;
        if ($name === 'true') {
            $type = Token::T_TRUE;
        } elseif ($name === 'false') {
            $type = Token::T_FALSE;
        } elseif ($name === 'null') {
            $type = Token::T_NULL;
        }

        $this->emit($type, $name, $location);
    }

    private function comment()

    {
        $this->scanner->next();
        $next = $this->scanner->peek();
        while ($this->scanner->eof() === false && $next !== "\n" && $next !== "\r") {
            $this->scanner->next();
            $next = $this->scanner->peek();
        }
    }

    private function str()

    {
        $this->scanner->next();
        $location = $this->getLocation();
        $string = '';
        $previousChar = false;

        while (true) {
            if ($this->scanner->eof()) {
                throw $this->getError('Unclosed quote');
            }
            $next = $this->scanner->peek();
            if ($previousChar !== '\\' && $next === '"') {
                $this->scanner->next();
                break;
            }
            $previousChar = $this->scanner->next();
            $string .= $previousChar;
        }

        $string = json_decode('"' . $string . '"');
        $this->emit(Token::T_STRING, $string, $location);
    }

    private function integerPart()

    {
        $number = $this->scanner->next();
        $location = $this->getLocation();
        if ($number === '-') {
            if ($this->scanner->eof()) {
                throw $this->getError('Expected a digit but instead reached end');
            }
            $next = $this->scanner->peek();
            if (ctype_digit($next) === false) {
                throw $this->getError("Expected a digit but instead found \"{$next}\"");
            }
        }

        $next = $this->scanner->peek();
        if ($next === '0') {
            $number .= $this->scanner->next();
            return array($number, $location);
        }

        $next = $this->scanner->peek();
        while ($this->scanner->eof() === false && ctype_digit($next)) {
            $number .= $this->scanner->next();
            $next = $this->scanner->peek();
        }

        return array($number, $location);
    }

    private function fractionalPart()

    {
        $part = $this->scanner->next();

        if ($this->scanner->eof()) {
            throw $this->getError('Expected a digit but instead reached end');
        }

        $next = $this->scanner->peek();
        if (ctype_digit($next) === false) {
            throw $this->getError("Expected a digit but instead found \"{$next}\"");
        }

        $next = $this->scanner->peek();
        while ($this->scanner->eof() === false && ctype_digit($next)) {
            $part .= $this->scanner->next();
            $next = $this->scanner->peek();
        }

        return $part;
    }

    private function exponentPart()

    {
        $part = $this->scanner->next();

        if ($this->scanner->eof()) {
            throw $this->getError('Expected a digit but instead reached end');
        }

        $next = $this->scanner->peek();
        if ($next === '+' || $next === '-') {
            $part .= $this->scanner->next();
        }

        $next = $this->scanner->peek();
        if (ctype_digit($next) === false) {
            throw $this->getError("Expected a digit but instead found \"{$next}\"");
        }

        $next = $this->scanner->peek();
        while ($this->scanner->eof() === false && ctype_digit($next)) {
            $part .= $this->scanner->next();
            $next = $this->scanner->peek();
        }

        return $part;
    }

    private function number()

    {
        list ($integerPart, $location) = $this->integerPart();
        if ($this->scanner->eof()) {
            $this->emit(Token::T_INT, $integerPart, $location);
            return;
        }

        $next = $this->scanner->peek();
        if ($next !== '.' && $next !== 'e' && $next !== 'E') {
            $this->emit(Token::T_INT, $integerPart, $location);
            return;
        }

        $number = $integerPart;
        if ($next === '.') {
            $number .= $this->fractionalPart();
        }

        $next = $this->scanner->peek();
        if ($next === 'e' || $next === 'E') {
            $number .= $this->exponentPart();
        }

        $this->emit(Token::T_FLOAT, $number, $location);
    }

    /**
     * @param string $query
     *
     * @throws SyntaxError
     *
     * @return Token[]
     */
    public function lex($query)
    {
        $flags = PREG_SPLIT_NO_EMPTY;
        $chars = preg_split('//u', $query, -1, $flags);
        $scanner = new ScannerGeneric($chars);
        $this->scanner = new ScannerWithLocation($scanner);
        $this->tokens = array();
        $punctuators = array(
            '!' => Token::T_EXCLAMATION,
            '(' => Token::T_PAREN_LEFT,
            ')' => Token::T_PAREN_RIGHT,
            '{' => Token::T_BRACE_LEFT,
            '}' => Token::T_BRACE_RIGHT,
            ':' => Token::T_COLON,
            ',' => Token::T_COMMA,
            '[' => Token::T_BRACKET_LEFT,
            ']' => Token::T_BRACKET_RIGHT,
            '=' => Token::T_EQUAL,
            '|' => Token::T_PIPE,
        );

        while ($this->scanner->eof() === false) {

            $next = $this->scanner->peek();

            if (ctype_space($next)) {
                $this->scanner->next();
                continue;
            }

            if ($next === '#') {
                $this->comment();
                continue;
            }

            if ($next === '_' || ctype_alpha($next)) {
                $this->name();
                continue;
            }

            if ($next === '"') {
                $this->str();
                continue;
            }

            if ($next === '-' || ctype_digit($next)) {
                $this->number();
                continue;
            }

            if (isset($punctuators[$next])) {
                $this->emit($punctuators[$next], $this->scanner->next(), $this->getLocation());
                continue;
            }

            throw $this->getError("Unknown character: \"{$next}\"");
        }

        return $this->tokens;
    }
}


1			<?php
2
3			namespace HansOtt\GraphQL\Schema;
4
5			use HansOtt\GraphQL\Shared\ScannerGeneric;
6			use HansOtt\GraphQL\Shared\ScannerWithLocation;
7			use HansOtt\GraphQL\Shared\Lexer as LexerShared;
8
9			final class Lexer implements LexerShared
10			{
11			/**
12			* @var ScannerWithLocation
13			*/
14			private $scanner;
15			private $tokens;
16
17	9		private function emit($type, $value, $location)
18			{
19	9		$this->tokens[] = new Token($type, $value, $location);
20	9		}
21
22	9		private function getLocation()
23			{
24	9		$line = $this->scanner->getLine();
25	9		$column = $this->scanner->getColumn();
26
27	9		return new Location($line, $column);
28			}
29
30			private function getError($message)
31			{
32			$line = $this->scanner->getLine();
33			$column = $this->scanner->getColumn();
34
35			return new SyntaxError($message . " (line {$line}, column {$column})");
36			}
37
38	9		private function name()
39			{
40	9		$name = $this->scanner->next();
41	9		$location = $this->getLocation();
42
43	9		if ($this->scanner->eof()) {
44			$this->emit(Token::T_NAME, $name, $location);
45			return;
46			}
47
48	9		$next = $this->scanner->peek();
49	9	View Code Duplication	while ($next === '_' \|\| ctype_alpha($next) \|\| ctype_digit($next)) {
			0 ignored issues – show Duplication introduced 2017-09-23 18:42 UTC by Report Bug Copy Issue Report This code seems to be duplicated across your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
50	9		$name .= $this->scanner->next();
51	9		if ($this->scanner->eof()) {
52			break;
53			}
54	9		$next = $this->scanner->peek();
55	9		}
56
57	9		$type = Token::T_NAME;
58	9		if ($name === 'true') {
59			$type = Token::T_TRUE;
60	9		} elseif ($name === 'false') {
61	3		$type = Token::T_FALSE;
62	9		} elseif ($name === 'null') {
63			$type = Token::T_NULL;
64			}
65
66	9		$this->emit($type, $name, $location);
67	9		}
68
69		View Code Duplication	private function comment()
			0 ignored issues – show Duplication introduced 2017-09-23 18:42 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
70			{
71			$this->scanner->next();
72			$next = $this->scanner->peek();
73			while ($this->scanner->eof() === false && $next !== "\n" && $next !== "\r") {
74			$this->scanner->next();
75			$next = $this->scanner->peek();
76			}
77			}
78
79		View Code Duplication	private function str()
			0 ignored issues – show Duplication introduced 2017-09-23 18:42 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
80			{
81			$this->scanner->next();
82			$location = $this->getLocation();
83			$string = '';
84			$previousChar = false;
85
86			while (true) {
87			if ($this->scanner->eof()) {
88			throw $this->getError('Unclosed quote');
89			}
90			$next = $this->scanner->peek();
91			if ($previousChar !== '\\' && $next === '"') {
92			$this->scanner->next();
93			break;
94			}
95			$previousChar = $this->scanner->next();
96			$string .= $previousChar;
97			}
98
99			$string = json_decode('"' . $string . '"');
100			$this->emit(Token::T_STRING, $string, $location);
101			}
102
103	3	View Code Duplication	private function integerPart()
			0 ignored issues – show Duplication introduced 2017-09-23 18:42 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
104			{
105	3		$number = $this->scanner->next();
106	3		$location = $this->getLocation();
107	3		if ($number === '-') {
108			if ($this->scanner->eof()) {
109			throw $this->getError('Expected a digit but instead reached end');
110			}
111			$next = $this->scanner->peek();
112			if (ctype_digit($next) === false) {
113			throw $this->getError("Expected a digit but instead found \"{$next}\"");
114			}
115			}
116
117	3		$next = $this->scanner->peek();
118	3		if ($next === '0') {
119			$number .= $this->scanner->next();
120			return array($number, $location);
121			}
122
123	3		$next = $this->scanner->peek();
124	3		while ($this->scanner->eof() === false && ctype_digit($next)) {
125			$number .= $this->scanner->next();
126			$next = $this->scanner->peek();
127			}
128
129	3		return array($number, $location);
130			}
131
132	3	View Code Duplication	private function fractionalPart()
			0 ignored issues – show Duplication introduced 2017-09-23 18:42 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
133			{
134	3		$part = $this->scanner->next();
135
136	3		if ($this->scanner->eof()) {
137			throw $this->getError('Expected a digit but instead reached end');
138			}
139
140	3		$next = $this->scanner->peek();
141	3		if (ctype_digit($next) === false) {
142			throw $this->getError("Expected a digit but instead found \"{$next}\"");
143			}
144
145	3		$next = $this->scanner->peek();
146	3		while ($this->scanner->eof() === false && ctype_digit($next)) {
147	3		$part .= $this->scanner->next();
148	3		$next = $this->scanner->peek();
149	3		}
150
151	3		return $part;
152			}
153
154		View Code Duplication	private function exponentPart()
			0 ignored issues – show Duplication introduced 2017-09-23 18:42 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
155			{
156			$part = $this->scanner->next();
157
158			if ($this->scanner->eof()) {
159			throw $this->getError('Expected a digit but instead reached end');
160			}
161
162			$next = $this->scanner->peek();
163			if ($next === '+' \|\| $next === '-') {
164			$part .= $this->scanner->next();
165			}
166
167			$next = $this->scanner->peek();
168			if (ctype_digit($next) === false) {
169			throw $this->getError("Expected a digit but instead found \"{$next}\"");
170			}
171
172			$next = $this->scanner->peek();
173			while ($this->scanner->eof() === false && ctype_digit($next)) {
174			$part .= $this->scanner->next();
175			$next = $this->scanner->peek();
176			}
177
178			return $part;
179			}
180
181	3	View Code Duplication	private function number()
			0 ignored issues – show Duplication introduced 2017-09-23 18:42 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
182			{
183	3		list ($integerPart, $location) = $this->integerPart();
184	3		if ($this->scanner->eof()) {
185			$this->emit(Token::T_INT, $integerPart, $location);
186			return;
187			}
188
189	3		$next = $this->scanner->peek();
190	3		if ($next !== '.' && $next !== 'e' && $next !== 'E') {
191			$this->emit(Token::T_INT, $integerPart, $location);
192			return;
193			}
194
195	3		$number = $integerPart;
196	3		if ($next === '.') {
197	3		$number .= $this->fractionalPart();
198	3		}
199
200	3		$next = $this->scanner->peek();
201	3		if ($next === 'e' \|\| $next === 'E') {
202			$number .= $this->exponentPart();
203			}
204
205	3		$this->emit(Token::T_FLOAT, $number, $location);
206	3		}
207
208			/**
209			* @param string $query
210			*
211			* @throws SyntaxError
212			*
213			* @return Token[]
214			*/
215	9		public function lex($query)
216			{
217	9		$flags = PREG_SPLIT_NO_EMPTY;
218	9		$chars = preg_split('//u', $query, -1, $flags);
219	9		$scanner = new ScannerGeneric($chars);
220	9		$this->scanner = new ScannerWithLocation($scanner);
221	9		$this->tokens = array();
222			$punctuators = array(
223	9		'!' => Token::T_EXCLAMATION,
224	9		'(' => Token::T_PAREN_LEFT,
225	9		')' => Token::T_PAREN_RIGHT,
226	9		'{' => Token::T_BRACE_LEFT,
227	9		'}' => Token::T_BRACE_RIGHT,
228	9		':' => Token::T_COLON,
229	9		',' => Token::T_COMMA,
230	9		'[' => Token::T_BRACKET_LEFT,
231	9		']' => Token::T_BRACKET_RIGHT,
232	9		'=' => Token::T_EQUAL,
233	9		'\|' => Token::T_PIPE,
234	9		);
235
236	9	View Code Duplication	while ($this->scanner->eof() === false) {
			0 ignored issues – show Duplication introduced 2017-09-23 18:42 UTC by Report Bug Copy Issue Report This code seems to be duplicated across your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
237	9		$next = $this->scanner->peek();
238
239	9		if (ctype_space($next)) {
240	9		$this->scanner->next();
241	9		continue;
242			}
243
244	9		if ($next === '#') {
245			$this->comment();
246			continue;
247			}
248
249	9		if ($next === '_' \|\| ctype_alpha($next)) {
250	9		$this->name();
251	9		continue;
252			}
253
254	9		if ($next === '"') {
255			$this->str();
256			continue;
257			}
258
259	9		if ($next === '-' \|\| ctype_digit($next)) {
260	3		$this->number();
261	3		continue;
262			}
263
264	9		if (isset($punctuators[$next])) {
265	9		$this->emit($punctuators[$next], $this->scanner->next(), $this->getLocation());
266	9		continue;
267			}
268
269			throw $this->getError("Unknown character: \"{$next}\"");
270			}
271
272	9		return $this->tokens;
273			}
274			}
275

hansott / graphql-language