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Improve tokenizer regex matching #131

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merged 4 commits into from
Jun 22, 2024
Merged

Improve tokenizer regex matching #131

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24d857e
Use atomic group for regex keywords matching
mvorisek May 31, 2024
7d3ff7b
Build regexes only once
mvorisek May 31, 2024
19bb3ab
Minimize capturing groups in tokenizer regexes
mvorisek Jun 3, 2024
fda3d6e
Build regexes from lists using deduplicated function
mvorisek Jun 2, 2024
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104 changes: 47 additions & 57 deletions src/Tokenizer.php
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Original file line number Diff line number Diff line change
Expand Up @@ -720,11 +720,13 @@ final class Tokenizer

// Regular expressions for tokenizing

private readonly string $regexBoundaries;
private readonly string $regexReserved;
private readonly string $regexReservedNewline;
private readonly string $regexReservedToplevel;
private readonly string $regexFunction;
private readonly string $nextTokenRegexNumber;
private readonly string $nextTokenRegexBoundaryCharacter;
private readonly string $nextTokenRegexReservedToplevel;
private readonly string $nextTokenRegexReservedNewline;
private readonly string $nextTokenRegexReserved;
private readonly string $nextTokenRegexFunction;
private readonly string $nextTokenRegexNonReserved;

/**
* Punctuation that can be used as a boundary between other tokens
Expand Down Expand Up @@ -769,25 +771,30 @@ public function __construct()
return array_keys($valuesMap);
};

// Set up regular expressions
$this->regexBoundaries = '(' . implode(
'|',
$this->quoteRegex($this->boundaries),
) . ')';
$this->regexReserved = '(' . implode(
'|',
$this->quoteRegex($sortByLengthFx($this->reserved)),
) . ')';
$this->regexReservedToplevel = str_replace(' ', '\s+', '(' . implode(
'|',
$this->quoteRegex($sortByLengthFx($this->reservedToplevel)),
) . ')');
$this->regexReservedNewline = str_replace(' ', '\s+', '(' . implode(
'|',
$this->quoteRegex($sortByLengthFx($this->reservedNewline)),
) . ')');
$buildRegexFromListFx = static function ($values) use ($sortByLengthFx) {
return '(?>' . implode(
'|',
array_map(
static fn ($v) => preg_quote($v, '/'),
$sortByLengthFx($values),
),
) . ')';
};

$this->regexFunction = '(' . implode('|', $this->quoteRegex($sortByLengthFx($this->functions))) . ')';
// Set up regular expressions
$regexBoundaries = $buildRegexFromListFx($this->boundaries);
$regexReserved = $buildRegexFromListFx($this->reserved);
$regexReservedToplevel = str_replace(' ', '\s+', $buildRegexFromListFx($this->reservedToplevel));
$regexReservedNewline = str_replace(' ', '\s+', $buildRegexFromListFx($this->reservedNewline));
$regexFunction = $buildRegexFromListFx($this->functions);

$this->nextTokenRegexNumber = '/\G(?:\d+(?:\.\d+)?|0x[\da-fA-F]+|0b[01]+)(?=$|\s|"\'`|' . $regexBoundaries . ')/';
$this->nextTokenRegexBoundaryCharacter = '/\G' . $regexBoundaries . '/';
$this->nextTokenRegexReservedToplevel = '/\G' . $regexReservedToplevel . '(?=$|\s|' . $regexBoundaries . ')/';
$this->nextTokenRegexReservedNewline = '/\G' . $regexReservedNewline . '(?=$|\s|' . $regexBoundaries . ')/';
$this->nextTokenRegexReserved = '/\G' . $regexReserved . '(?=$|\s|' . $regexBoundaries . ')/';
$this->nextTokenRegexFunction = '/\G' . $regexFunction . '(?=\s*\()/';
$this->nextTokenRegexNonReserved = '/\G.*?(?=$|\s|["\'`]|' . $regexBoundaries . ')/';
}

/**
Expand Down Expand Up @@ -829,7 +836,6 @@ public function tokenize(string $string): Cursor
*/
private function createNextToken(string $string, string $upper, int $offset, Token|null $previous = null): Token
{
$matches = [];
// Whitespace
if (preg_match('/\G\s+/', $string, $matches, 0, $offset)) {
return new Token(Token::TOKEN_TYPE_WHITESPACE, $matches[0]);
Expand Down Expand Up @@ -883,9 +889,9 @@ private function createNextToken(string $string, string $upper, int $offset, Tok
$value = $firstChar . $this->getNextQuotedString($string, $offset + 1);
} else {
// Non-quoted variable name
preg_match('/\G(' . $firstChar . '[\w.$]+)/', $string, $matches, 0, $offset);
preg_match('/\G[@:][\w.$]+/', $string, $matches, 0, $offset);
if ($matches) {
$value = $matches[1];
$value = $matches[0];
}
}

Expand All @@ -897,19 +903,19 @@ private function createNextToken(string $string, string $upper, int $offset, Tok
// Number (decimal, binary, or hex)
if (
preg_match(
'/\G(\d+(\.\d+)?|0x[\da-fA-F]+|0b[01]+)($|\s|"\'`|' . $this->regexBoundaries . ')/',
$this->nextTokenRegexNumber,
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$string,
$matches,
0,
$offset,
)
) {
return new Token(Token::TOKEN_TYPE_NUMBER, $matches[1]);
return new Token(Token::TOKEN_TYPE_NUMBER, $matches[0]);
}

// Boundary Character (punctuation and symbols)
if (preg_match('/\G(' . $this->regexBoundaries . ')/', $string, $matches, 0, $offset)) {
return new Token(Token::TOKEN_TYPE_BOUNDARY, $matches[1]);
if (preg_match($this->nextTokenRegexBoundaryCharacter, $string, $matches, 0, $offset)) {
return new Token(Token::TOKEN_TYPE_BOUNDARY, $matches[0]);
}

// A reserved word cannot be preceded by a '.'
Expand All @@ -918,7 +924,7 @@ private function createNextToken(string $string, string $upper, int $offset, Tok
// Top Level Reserved Word
if (
preg_match(
'/\G(' . $this->regexReservedToplevel . ')($|\s|' . $this->regexBoundaries . ')/',
$this->nextTokenRegexReservedToplevel,
$upper,
$matches,
0,
Expand All @@ -927,14 +933,14 @@ private function createNextToken(string $string, string $upper, int $offset, Tok
) {
return new Token(
Token::TOKEN_TYPE_RESERVED_TOPLEVEL,
substr($string, $offset, strlen($matches[1])),
substr($string, $offset, strlen($matches[0])),
);
}

// Newline Reserved Word
if (
preg_match(
'/\G(' . $this->regexReservedNewline . ')($|\s|' . $this->regexBoundaries . ')/',
$this->nextTokenRegexReservedNewline,
$upper,
$matches,
0,
Expand All @@ -943,14 +949,14 @@ private function createNextToken(string $string, string $upper, int $offset, Tok
) {
return new Token(
Token::TOKEN_TYPE_RESERVED_NEWLINE,
substr($string, $offset, strlen($matches[1])),
substr($string, $offset, strlen($matches[0])),
);
}

// Other Reserved Word
if (
preg_match(
'/\G(' . $this->regexReserved . ')($|\s|' . $this->regexBoundaries . ')/',
$this->nextTokenRegexReserved,
$upper,
$matches,
0,
Expand All @@ -959,40 +965,24 @@ private function createNextToken(string $string, string $upper, int $offset, Tok
) {
return new Token(
Token::TOKEN_TYPE_RESERVED,
substr($string, $offset, strlen($matches[1])),
substr($string, $offset, strlen($matches[0])),
);
}
}

// A function must be succeeded by '('
// this makes it so "count(" is considered a function, but "count" alone is not
// function
if (preg_match('/\G(' . $this->regexFunction . '[(]|\s|[)])/', $upper, $matches, 0, $offset)) {
// this makes it so "count(" is considered a function, but "count" alone is not function
if (preg_match($this->nextTokenRegexFunction, $upper, $matches, 0, $offset)) {
return new Token(
Token::TOKEN_TYPE_RESERVED,
substr($string, $offset, strlen($matches[1]) - 1),
substr($string, $offset, strlen($matches[0])),
);
}

// Non reserved word
preg_match('/\G(.*?)($|\s|["\'`]|' . $this->regexBoundaries . ')/', $string, $matches, 0, $offset);

return new Token(Token::TOKEN_TYPE_WORD, $matches[1]);
}
preg_match($this->nextTokenRegexNonReserved, $string, $matches, 0, $offset);

/**
* Helper function for building regular expressions for reserved words and boundary characters
*
* @param string[] $strings The strings to be quoted
*
* @return string[] The quoted strings
*/
private function quoteRegex(array $strings): array
{
return array_map(
static fn (string $string): string => preg_quote($string, '/'),
$strings,
);
return new Token(Token::TOKEN_TYPE_WORD, $matches[0]);
}

private function getNextQuotedString(string $string, int $offset): string
Expand Down
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