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<?php
/** @license MIT
* Copyright 2021 Dustin Wilson et al.
* See LICENSE file for details */
declare(strict_types=1);
namespace dW\Lit;
use dW\Lit\Grammar\{
BaseReference,
Pattern,
Reference,
RepositoryReference
};
use dW\Lit\Scope\{
Filter,
Parser as ScopeParser
};
class Tokenizer {
protected Data $data;
protected Grammar $grammar;
protected int $offset = 0;
protected ?Pattern $activeInjection = null;
protected array $ruleStack;
protected array $scopeStack;
protected int $debug = 0;
protected int $debugCount = 0;
protected const SCOPE_RESOLVE_REGEX = '/\$(\d+)|\${(\d+):\/(downcase|upcase)}/S';
protected const ANCHOR_CHECK_REGEX = '/(?<!\\\)\\\([AGzZ])/S';
public function __construct(Data $data, Grammar $grammar) {
$this->data = $data;
$this->grammar = $grammar;
$this->ruleStack = [ $this->grammar ];
$this->scopeStack = [ $this->grammar->scopeName ];
}
public function tokenize(): \Generator {
foreach ($this->data->get() as $lineNumber => $line) {
$this->debug = $lineNumber;
$this->debugCount = 0;
$this->offset = 0;
$lineLength = strlen($line);
$tokens = ($lineLength > 0) ? $this->tokenizeLine($line) : [];
// Output a token for everything else contained on the line including the
// newline or just a newline if there weren't any spare characters left on the
// line. If it is the last line, and there's nothing else remaining on the line
// then output no additional token.
if ($this->offset < $lineLength) {
$tokens[] = new Token(
$this->scopeStack,
substr($line, $this->offset, $lineLength - $this->offset) . ((!$this->data->lastLine) ? "\n" : '')
);
$this->debugCount++;
} elseif (!$this->data->lastLine) {
$tokens[] = new Token(
$this->scopeStack,
"\n"
);
$this->debugCount++;
}
yield $lineNumber => $tokens;
}
}
protected function resolveScopeName(string $scopeName, array $match): string {
return preg_replace_callback(self::SCOPE_RESOLVE_REGEX, function($m) use($match) {
$replacement = $match[(int)$m[1]][0] ?? $m[1];
$command = $m[2] ?? null;
switch ($command) {
case 'downcase': return strtolower($replacement);
break;
case 'upcase': return strtoupper($replacement);
break;
default: return $replacement;
}
}, $scopeName);
}
protected function tokenizeLine(string $line): array {
$tokens = [];
$lineLength = strlen($line);
while (true) {
if ($this->activeInjection === null && $this->grammar->injections !== null) {
foreach ($this->grammar->injections as $selector => $injection) {
$selector = ScopeParser::parseSelector($selector);
if ($selector->matches($this->scopeStack)) {
$prefix = $selector->getPrefix($this->scopeStack);
if ($prefix === Filter::PREFIX_LEFT || $prefix === Filter::PREFIX_BOTH) {
$this->scopeStack[] = $injection;
$this->activeInjection = $injection;
break;
}
}
}
}
$currentRules = end($this->ruleStack)->patterns;
$currentRulesCount = count($currentRules);
$closestMatch = null;
// Iterate through the rules to find matches for the line at the current offset.
for ($i = 0; $i < $currentRulesCount; $i++) {
while (true) {
$rule = $currentRules[$i];
// If the rule is a Pattern
if ($rule instanceof Pattern) {
// Throw out pattern regexes with anchors that should match the current line.
// This is necessary because the tokenizer is fed data line by line.
if (preg_match(self::ANCHOR_CHECK_REGEX, $rule->match, $validRegexMatch) === 1) {
if (
// \A anchors match the beginning of the whole string, not just this line
($validRegexMatch[1] === 'A' && !$this->data->firstLine) ||
// \z anchors match the end of the whole string, not just this line
($validRegexMatch[1] === 'z' && !$this->data->lastLine) ||
// \Z anchors match the end of the whole string or before the final newline if
// there's a trailing newline in the string
($validRegexMatch[1] === 'Z' && !$this->data->lastLineBeforeFinalNewLine)
) {
continue 2;
}
}
if (preg_match($rule->match, "$line\n", $match, PREG_OFFSET_CAPTURE, $this->offset)) {
// If the match's offset is the same as the current offset then it is the
// closest match. There's no need to iterate anymore through the patterns.
if ($match[0][1] === $this->offset) {
$closestMatch = [
'match' => $match,
'pattern' => $rule
];
break 2;
}
// Otherwise, if the closest match is currently null or the match's offset is
// less than the closest match's offset then set the match as the closest match
// and continue looking for a closer one.
elseif ($closestMatch === null || $match[0][1] < $closestMatch['match'][0][1]) {
$closestMatch = [
'match' => $match,
'pattern' => $rule
];
}
}
}
// Otherwise, if the rule is a Reference then retrieve its patterns, splice into
// the rule list, and reprocess the rule.
elseif ($rule instanceof Reference) {
if (!$rule instanceof BaseReference) {
$obj = $rule->get();
if ($obj instanceof Grammar || ($rule instanceof RepositoryReference && $obj->match === null)) {
$obj = $obj->patterns;
}
} else {
$obj = $this->grammar->patterns;
}
array_splice($currentRules, $i, 1, ($obj instanceof Pattern) ? [ $obj ] : $obj);
$currentRulesCount = count($currentRules);
continue;
}
break;
}
}
// If there were a match above...
if ($closestMatch !== null) {
$match = $closestMatch['match'];
$pattern = $closestMatch['pattern'];
// If the subpattern begins after the offset then create a token from the bits
// of the line in-between the last token and the one(s) about to be created.
if ($match[0][1] > $this->offset) {
$tokens[] = new Token(
$this->scopeStack,
substr($line, $this->offset, $match[0][1] - $this->offset)
);
$this->debugCount++;
$this->offset = $match[0][1];
}
// Add the name to the scope stack if present.
if ($pattern->name !== null) {
$this->scopeStack[] = $this->resolveScopeName($pattern->name, $match);
}
// If a rule has captures iterate through each of the matched subpatterns and
// create tokens from the captures.
if ($pattern->captures !== null) {
foreach ($match as $k => $m) {
if ($m[0] === '' || ($k === 0 && !isset($pattern->captures[0]))) {
continue;
}
// If the capture begins after the offset then create a token from the bits of
// the line in-between the last token and the one(s) about to be created.
if ($k > 0 && $m[1] > $this->offset) {
$tokens[] = new Token(
$this->scopeStack,
substr($line, $this->offset, $m[1] - $this->offset)
);
$this->debugCount++;
$this->offset = $m[1];
}
// If the capture has a name add it to the scope stack.
if ($pattern->captures[$k]->name !== null) {
$this->scopeStack[] = $this->resolveScopeName($pattern->captures[$k]->name, $match);
}
// If the capture has patterns of its own add the capture to the rule stack,
// process the patterns, and then pop the capture off the stack.
if ($pattern->captures[$k]->patterns !== null) {
$this->ruleStack[] = $pattern->captures[$k];
$tokens = [ ...$tokens, ...$this->tokenizeLine($line) ];
// If the offset is before the end of the capture then create a token from the
// bits of the capture from the offset until the end of the capture.
$endOffset = $m[1] + strlen($m[0]);
if ($endOffset > $this->offset) {
$tokens[] = new Token(
$this->scopeStack,
substr($line, $this->offset, $endOffset - $this->offset)
);
$this->debugCount++;
$this->offset = $endOffset;
}
array_pop($this->ruleStack);
}
// Otherwise, create a token for the capture.
else {
$tokens[] = new Token(
$this->scopeStack,
$m[0]
);
$this->debugCount++;
}
// Pop the capture's name off the scope stack.
if ($pattern->captures[$k]->name !== null) {
array_pop($this->scopeStack);
}
$this->offset = $m[1] + strlen($m[0]);
}
}
// Otherwise, if the rule doesn't have captures then a token is created from the
// entire match, but only if the matched text isn't empty.
elseif ($match[0][0] !== '') {
$tokens[] = new Token(
$this->scopeStack,
$match[0][0]
);
$this->offset = $match[0][1] + strlen($match[0][0]);
$this->debugCount++;
}
// If the pattern is a begin pattern and has a content name then add that to the
// scope stack before processing the children.
if ($pattern->beginPattern && $pattern->contentName !== null) {
$this->scopeStack[] = $this->resolveScopeName($pattern->contentName, $match);
}
$this->ruleStack[] = $pattern;
// If the rule has patterns process tokens from its subpatterns.
if ($pattern->patterns !== null && $this->offset < $lineLength) {
$tokens = [ ...$tokens, ...$this->tokenizeLine($line) ];
}
// If the offset is before the end of the match then create a token from the
// bits of the match from the offset until the end of the match.
$endOffset = $match[0][1] + strlen($match[0][0]);
if ($endOffset > $this->offset) {
$tokens[] = new Token(
$this->scopeStack,
substr($line, $this->offset, $endOffset - $this->offset)
);
$this->debugCount++;
$this->offset = $endOffset;
}
if (!$pattern->beginPattern) {
if ($pattern->endPattern) {
while (!end($this->ruleStack)->beginPattern) {
$popped = array_pop($this->ruleStack);
if ($popped->name !== null) {
array_pop($this->scopeStack);
}
// If what was just popped is the active injection then remove it, too.
if ($popped === $this->activeInjection) {
$this->activeInjection = null;
}
}
}
$popped = array_pop($this->ruleStack);
// If what was just popped is a begin pattern and has a content name pop it off
// the scope stack.
if ($popped->beginPattern && $popped->contentName !== null) {
array_pop($this->scopeStack);
}
if ($popped->name !== null) {
array_pop($this->scopeStack);
}
// If what was just popped is the active injection then remove it, too.
if ($popped === $this->activeInjection) {
$this->activeInjection = null;
}
}
// If the offset isn't at the end of the line then look for more matches.
if ($this->offset !== $lineLength) {
continue;
}
}
if ($this->activeInjection === null && $this->grammar->injections !== null) {
foreach ($this->grammar->injections as $selector => $injection) {
$selector = ScopeParser::parseSelector($selector);
if ($selector->matches($this->scopeStack) && $selector->getPrefix($this->scopeStack) !== Filter::PREFIX_LEFT) {
$this->ruleStack[] = $injection;
$this->activeInjection = $injection;
if ($this->offset < $lineLength) {
continue 2;
}
}
}
}
break;
}
return $tokens;
}
}