/s', $code, $matches)) {
return [];
}
$defs = [];
foreach ($matches[1] as $grammar) {
$defs = array_merge($defs, parse_grammar($grammar));
}
return $defs;
}
function parse_grammar($grammar) {
$defTexts = explode("\n\n", trim($grammar));
$defs = [];
foreach ($defTexts as $defText) {
if (!preg_match('/^([a-zA-Z0-9-]+)(::?)(\s+one\s+of)?\n(.*?)$/s', $defText, $matches)) {
throw new \Exception('Invalid definition');
}
$rules = array_map('Grammar\parse_rule', explode("\n", $matches[4]));
$defs[] = new Definition(
$matches[1], $matches[2] === '::', $matches[3] !== '', $rules
);
}
return $defs;
}
function parse_rule($rule) {
$regex = <<<'REGEX'
/(?:
'[^']*(?:''[^']*)*'
| "[^"]*(?:""[^"]*)*"
)(*SKIP)(*F)|\s+/x
REGEX;
$parts = array_map('Grammar\parse_rule_part', preg_split($regex, trim($rule)));
return new Rule($parts);
}
function parse_rule_part($part) {
if (substr($part, -1) === '?') {
return new Opt(parse_rule_part(substr($part, 0, -1)));
}
if ($part[0] === "'") {
$contents = str_replace("''", "'", substr($part, 1, -1));
return new Plain($contents);
}
if ($part[0] === '"') {
$contents = str_replace('""', '"', substr($part, 1, -1));
return new Plain($contents);
}
return new Reference($part);
}
function render_grammar($defs, $names, $currentFile) {
$ctx = new RenderContext;
$ctx->names = $names;
$ctx->currentFile = $currentFile;
$result = [];
foreach ($defs as $def) {
$result[] = $def->render($ctx);
}
return "\n" . implode("\n\n", $result) . "\n";
}
class RenderContext {
public $names;
public $currentFile;
}
class Definition {
public $name, $isLexical, $isOneOf, $rules;
public function __construct($name, $isLexical, $isOneOf, $rules) {
$this->name = $name;
$this->isLexical = $isLexical;
$this->isOneOf = $isOneOf;
$this->rules = $rules;
}
public function render($ctx) {
$sep = $this->isLexical ? '::' : ':';
$oneOf = $this->isOneOf ? ' one of' : '';
$result = "name\">$this->name$sep$oneOf";
foreach ($this->rules as $rule) {
$result .= "\n " . $rule->render($ctx);
}
return $result;
}
}
class Rule {
public $parts;
public function __construct($parts) {
$this->parts = $parts;
}
public function render($ctx) {
$parts = [];
foreach ($this->parts as $part) {
$parts[] = $part->render($ctx);
}
return implode(' ', $parts);
}
}
class Reference {
public $name;
public function __construct($name) {
$this->name = $name;
}
public function render($ctx) {
if (!isset($ctx->names[$this->name])) {
throw new \Exception("Reference to unknown name $this->name");
}
$fileName = $ctx->names[$this->name];
$anchor = "#grammar-$this->name";
if ($fileName != $ctx->currentFile) {
$anchor = $fileName . $anchor;
}
return "$this->name";
}
}
class Plain {
public $string;
public function __construct($string) {
$this->string = $string;
}
public function render($ctx) {
return htmlspecialchars($this->string);
}
}
class Opt {
public $inner;
public function __construct($inner) {
$this->inner = $inner;
}
public function render($ctx) {
return $this->inner->render($ctx) . 'opt';
}
}