Lexer - Code Metrics - Inspection of "master" - hansott/graphql-language - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#2)

by Hans

created 2017-12-01 19:35 UTC

Lexer C

↳ Parent: Project

Complexity

Total Complexity

Size/Duplication

Total Lines	305
Duplicated Lines	49.84 %

Coupling/Cohesion

Components	1
Dependencies	5

Test Coverage

Coverage

84.77%

Importance

Changes

Metric	Value
wmc	66
lcom	1
cbo	5
dl	152
loc	305
ccs	167
cts	197
cp	0.8477
rs	5.7474
c	0
b	0
f	0

12 Methods

Rating	Name	Duplication	Size	Complexity
A	emit()	0	4	1
A	getLocation()	0	7	1
A	getError()	0	7	1
C	name()	7	38	13
A	comment()	9	9	4
A	spread()	0	20	3
B	str()	23	23	5
C	integerPart()	0	32	7
B	fractionalPart()	21	21	5
C	exponentPart()	26	26	7
C	number()	26	26	8
C	lex()	40	65	11

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\Query;

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 === 'query') {
            $type = Token::T_QUERY;
        } elseif ($name === 'mutation') {
            $type = Token::T_MUTATION;
        } elseif ($name === 'subscription') {
            $type = Token::T_SUBSCRIPTION;
        } elseif ($name === 'fragment') {
            $type = Token::T_FRAGMENT;
        } elseif ($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 spread()
    {
        $points = $this->scanner->next();
        $location = $this->getLocation();
        $next = $this->scanner->peek();

        if ($next !== '.') {
            throw $this->getError("Expected \".\" but instead found \"{$next}\"");
        }

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

        if ($next !== '.') {
            throw $this->getError("Expected \".\" but instead found \"{$next}\"");
        }

        $points .= $this->scanner->next();
        $this->emit(Token::T_SPREAD, $points, $location);
    }

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

        $location = $this->getLocation();
        $next = $this->scanner->peek();
        $number = '';
        if ($next === '-') {
            $number .= $next;
            $this->scanner->next();
            if ($this->scanner->eof()) {
                throw $this->getError('Expected an integer or a float but instead reached end');
            }
        }

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

        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->spread();
                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\Query;
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 $tokens;
16
17	66		private function emit($type, $value, $location)
18			{
19	66		$this->tokens[] = new Token($type, $value, $location);
20	66		}
21
22	93		private function getLocation()
23			{
24	93		$line = $this->scanner->getLine();
25	93		$column = $this->scanner->getColumn();
26
27	93		return new Location($line, $column);
28			}
29
30	27		private function getError($message)
31			{
32	27		$line = $this->scanner->getLine();
33	27		$column = $this->scanner->getColumn();
34
35	27		return new SyntaxError($message . " (line {$line}, column {$column})");
36			}
37
38	63		private function name()
39			{
40	63		$name = $this->scanner->next();
41	63		$location = $this->getLocation();
42
43	63		if ($this->scanner->eof()) {
44			$this->emit(Token::T_NAME, $name, $location);
45			return;
46			}
47
48	63		$next = $this->scanner->peek();
49	63	View Code Duplication	while ($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	63		$name .= $this->scanner->next();
51	63		if ($this->scanner->eof()) {
52	3		break;
53			}
54	63		$next = $this->scanner->peek();
55	63		}
56
57	63		$type = Token::T_NAME;
58	63		if ($name === 'query') {
59	18		$type = Token::T_QUERY;
60	63		} elseif ($name === 'mutation') {
61			$type = Token::T_MUTATION;
62	63		} elseif ($name === 'subscription') {
63			$type = Token::T_SUBSCRIPTION;
64	63		} elseif ($name === 'fragment') {
65	6		$type = Token::T_FRAGMENT;
66	63		} elseif ($name === 'true') {
67	3		$type = Token::T_TRUE;
68	63		} elseif ($name === 'false') {
69	3		$type = Token::T_FALSE;
70	63		} elseif ($name === 'null') {
71	3		$type = Token::T_NULL;
72	3		}
73
74	63		$this->emit($type, $name, $location);
75	63		}
76
77		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...
78			{
79			$this->scanner->next();
80			$next = $this->scanner->peek();
81			while ($this->scanner->eof() === false && $next !== "\n" && $next !== "\r") {
82			$this->scanner->next();
83			$next = $this->scanner->peek();
84			}
85			}
86
87	6		private function spread()
88			{
89	6		$points = $this->scanner->next();
90	6		$location = $this->getLocation();
91	6		$next = $this->scanner->peek();
92
93	6		if ($next !== '.') {
94			throw $this->getError("Expected \".\" but instead found \"{$next}\"");
95			}
96
97	6		$points .= $this->scanner->next();
98	6		$next = $this->scanner->peek();
99
100	6		if ($next !== '.') {
101			throw $this->getError("Expected \".\" but instead found \"{$next}\"");
102			}
103
104	6		$points .= $this->scanner->next();
105	6		$this->emit(Token::T_SPREAD, $points, $location);
106	6		}
107
108	24	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...
109			{
110	24		$this->scanner->next();
111	24		$location = $this->getLocation();
112	24		$string = '';
113	24		$previousChar = false;
114
115	24		while (true) {
116	24		if ($this->scanner->eof()) {
117	3		throw $this->getError('Unclosed quote');
118			}
119	21		$next = $this->scanner->peek();
120	21		if ($previousChar !== '\\' && $next === '"') {
121	21		$this->scanner->next();
122	21		break;
123			}
124	21		$previousChar = $this->scanner->next();
125	21		$string .= $previousChar;
126	21		}
127
128	21		$string = json_decode('"' . $string . '"');
129	21		$this->emit(Token::T_STRING, $string, $location);
130	21		}
131
132	48		private function integerPart()
133			{
134	48		if ($this->scanner->eof()) {
135			throw $this->getError('Expected an integer or a float but instead reached end');
136			}
137
138	48		$location = $this->getLocation();
139	48		$next = $this->scanner->peek();
140	48		$number = '';
141	48		if ($next === '-') {
142	12		$number .= $next;
143	12		$this->scanner->next();
144	12		if ($this->scanner->eof()) {
145	3		throw $this->getError('Expected an integer or a float but instead reached end');
146			}
147	9		}
148
149	45		$next = $this->scanner->peek();
150	45		if ($next === '0') {
151	21		$number .= $next;
152	21		$this->scanner->next();
153	21		return array($number, $location);
154			}
155
156	24		$next = $this->scanner->peek();
157	24		while ($this->scanner->eof() === false && ctype_digit($next)) {
158	24		$number .= $this->scanner->next();
159	24		$next = $this->scanner->peek();
160	24		}
161
162	24		return array($number, $location);
163			}
164
165	21	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...
166			{
167	21		$part = $this->scanner->next();
168
169	21		if ($this->scanner->eof()) {
170	6		throw $this->getError('Expected a digit but instead reached end');
171			}
172
173	15		$next = $this->scanner->peek();
174	15		if (ctype_digit($next) === false) {
175			throw $this->getError("Expected a digit but instead found \"{$next}\"");
176			}
177
178	15		$next = $this->scanner->peek();
179	15		while ($this->scanner->eof() === false && ctype_digit($next)) {
180	15		$part .= $this->scanner->next();
181	15		$next = $this->scanner->peek();
182	15		}
183
184	15		return $part;
185			}
186
187	15	View Code Duplication	private function exponentPart()
			0 ignored issues – show Duplication introduced 2017-09-16 10:48 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...
188			{
189	15		$part = $this->scanner->next();
190
191	15		if ($this->scanner->eof()) {
192	9		throw $this->getError('Expected a digit but instead reached end');
193			}
194
195	6		$next = $this->scanner->peek();
196	6		if ($next === '+' \|\| $next === '-') {
197			$part .= $this->scanner->next();
198			}
199
200	6		$next = $this->scanner->peek();
201	6		if (ctype_digit($next) === false) {
202	6		throw $this->getError("Expected a digit but instead found \"{$next}\"");
203			}
204
205			$next = $this->scanner->peek();
206			while ($this->scanner->eof() === false && ctype_digit($next)) {
207			$part .= $this->scanner->next();
208			$next = $this->scanner->peek();
209			}
210
211			return $part;
212			}
213
214	48	View Code Duplication	private function number()
			0 ignored issues – show Duplication introduced 2017-09-23 18:42 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
215			{
216	48		list ($integerPart, $location) = $this->integerPart();
217	45		if ($this->scanner->eof()) {
218			$this->emit(Token::T_INT, $integerPart, $location);
219			return;
220			}
221
222	45		$next = $this->scanner->peek();
223	45		if ($next !== '.' && $next !== 'e' && $next !== 'E') {
224	24		$this->emit(Token::T_INT, $integerPart, $location);
225	24		return;
226			}
227
228	24		$number = $integerPart;
229	24		if ($next === '.') {
230	21		$number .= $this->fractionalPart();
231	15		}
232
233	18		$next = $this->scanner->peek();
234	18		if ($next === 'e' \|\| $next === 'E') {
235	15		$number .= $this->exponentPart();
236			}
237
238	3		$this->emit(Token::T_FLOAT, $number, $location);
239	3		}
240
241			/**
242			* @param string $query
243			*
244			* @throws SyntaxError
245			*
246			* @return Token[]
247			*/
248	96		public function lex($query)
249			{
250	96		$flags = PREG_SPLIT_NO_EMPTY;
251	96		$chars = preg_split('//u', $query, -1, $flags);
252	96		$scanner = new ScannerGeneric($chars);
253	96		$this->scanner = new ScannerWithLocation($scanner);
254	96		$this->tokens = array();
255			$punctuators = array(
256	96		'!' => Token::T_EXCLAMATION,
257	96		'$' => Token::T_DOLLAR,
258	96		'(' => Token::T_PAREN_LEFT,
259	96		')' => Token::T_PAREN_RIGHT,
260	96		'{' => Token::T_BRACE_LEFT,
261	96		'}' => Token::T_BRACE_RIGHT,
262	96		':' => Token::T_COLON,
263	96		',' => Token::T_COMMA,
264	96		'[' => Token::T_BRACKET_LEFT,
265	96		']' => Token::T_BRACKET_RIGHT,
266	96		'=' => Token::T_EQUAL,
267	96		'@' => Token::T_AT,
268	96		);
269
270	96	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...
271	93		$next = $this->scanner->peek();
272
273	93		if (ctype_space($next)) {
274	63		$this->scanner->next();
275	63		continue;
276			}
277
278	93		if ($next === '#') {
279			$this->comment();
280			continue;
281			}
282
283	93		if ($next === '_' \|\| ctype_alpha($next)) {
284	63		$this->name();
285	63		continue;
286			}
287
288	93		if ($next === '.') {
289	6		$this->spread();
290	6		continue;
291			}
292
293	93		if ($next === '"') {
294	24		$this->str();
295	21		continue;
296			}
297
298	90		if ($next === '-' \|\| ctype_digit($next)) {
299	48		$this->number();
300	24		continue;
301			}
302
303	66		if (isset($punctuators[$next])) {
304	66		$this->emit($punctuators[$next], $this->scanner->next(), $this->getLocation());
305	66		continue;
306			}
307
308			throw $this->getError("Unknown character: \"{$next}\"");
309			}
310
311	69		return $this->tokens;
312			}
313			}
314

hansott / graphql-language