phabel/php-parser
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Merge primary error recovery code

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The grammar does not yet actually implement error recovery.
This commit is contained in:
Nikita Popov 2015-02-02 23:25:34 +01:00
parent c8454271e1
commit 65f1adbe65
2 changed files with 100 additions and 17 deletions
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3
grammar/kmyacc.php.parser
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@ -20,7 +20,8 @@ class Parser extends ParserAbstract
protected $actionTableSize = #(YYLAST);
protected $gotoTableSize = #(YYGLAST);
protected $invalidToken = #(YYBADCH);
protected $invalidSymbol = #(YYBADCH);
protected $errorSymbol = #(YYINTERRTOK);
protected $defaultAction = #(YYDEFAULT);
protected $unexpectedTokenRule = #(YYUNEXPECTED);

114
lib/PhpParser/ParserAbstract.php
View File

@ -23,6 +23,8 @@ abstract class ParserAbstract
/** @var int Symbol number signifying an invalid token */
protected $invalidSymbol;
/** @var int Symbol number of error recovery token */
protected $errorSymbol;
/** @var int Action number signifying default action */
protected $defaultAction;
/** @var int Rule number signifying that an unexpected token was encountered */
@ -81,13 +83,34 @@ abstract class ParserAbstract
/** @var int Position in stacks (state stack, semantic value stack, attribute stack) */
protected $stackPos;
/** @var bool Whether to throw on first error */
protected $throwOnError;
/** @var Error[] Errors collected during last parse */
protected $errors;
/**
* Creates a parser instance.
*
* @param Lexer $lexer A lexer
* @param array $options Options array. The boolean 'throwOnError' option determined whether an exception should be
* thrown on first error, or if the parser should try to continue parsing the remaining code
* and build a partial AST.
*/
public function __construct(Lexer $lexer) {
public function __construct(Lexer $lexer, array $options = array()) {
$this->lexer = $lexer;
$this->errors = array();
$this->throwOnError = isset($options['throwOnError']) ? $options['throwOnError'] : true;
}
/**
* Get array of errors that occurred during the last parse.
*
* This method may only return multiple errors if the throwOnError option is disabled.
*
* @return Error[]
*/
public function getErrors() {
return $this->errors;
}
/**
@ -99,6 +122,7 @@ abstract class ParserAbstract
*/
public function parse($code) {
$this->lexer->startLexing($code);
$this->errors = array();
// We start off with no lookahead-token
$symbol = self::SYMBOL_NONE;
@ -123,6 +147,8 @@ abstract class ParserAbstract
// Current position in the stack(s)
$this->stackPos = 0;
$errorState = 0;
for (;;) {
//$this->traceNewState($state, $symbol);
@ -177,8 +203,13 @@ abstract class ParserAbstract
$endAttributes = $nextEndAttributes;
$symbol = self::SYMBOL_NONE;
if ($action < $this->YYNLSTATES)
if ($errorState) {
--$errorState;
}
if ($action < $this->YYNLSTATES) {
continue;
}
/* $yyn >= YYNLSTATES means shift-and-reduce */
$rule = $action - $this->YYNLSTATES;
@ -226,28 +257,71 @@ abstract class ParserAbstract
$stateStack[$this->stackPos] = $state;
$this->semStack[$this->stackPos] = $this->semValue;
$attributeStack[$this->stackPos] = $startAttributes;
if ($state < $this->YYNLSTATES)
break;
/* >= YYNLSTATES means shift-and-reduce */
$rule = $state - $this->YYNLSTATES;
} else {
/* error */
if ($expected = $this->getExpectedTokens($state)) {
$expectedString = ', expecting ' . implode(' or ', $expected);
} else {
$expectedString = '';
}
switch ($errorState) {
case 0:
$msg = $this->getErrorMessage($symbol, $state);
$error = new Error($msg, $startAttributes + $nextEndAttributes);
$this->errors[] = $error;
if ($this->throwOnError) {
throw $error;
}
// Break missing intentionally
case 1:
case 2:
$errorState = 3;
throw new Error(
'Syntax error, unexpected ' . $this->symbolToName[$symbol] . $expectedString,
$startAttributes + $nextEndAttributes
);
// Pop until error-expecting state uncovered
while (!(
(($idx = $this->actionBase[$state] + $this->errorSymbol) >= 0
&& $idx < $this->actionTableSize && $this->actionCheck[$idx] == $this->errorSymbol)
|| ($state < $this->YY2TBLSTATE
&& ($idx = $this->actionBase[$state + $this->YYNLSTATES] + $this->errorSymbol) >= 0
&& $idx < $this->actionTableSize && $this->actionCheck[$idx] == $this->errorSymbol)
) || ($action = $this->action[$idx]) == $this->defaultAction) { // Not totally sure about this
if ($this->stackPos <= 0) {
throw new Error('Could not recover from error');
}
$state = $stateStack[--$this->stackPos];
//$this->tracePop($state);
}
//$this->traceShift($this->errorSymbol);
$stateStack[++$this->stackPos] = $state = $action;
break;
case 3:
if ($symbol === 0) {
// Reached EOF
throw new Error('Could not recover from error');
}
//$this->traceDiscard($symbol);
$symbol = self::SYMBOL_NONE;
break 2;
}
}
if ($state < $this->YYNLSTATES) {
break;
}
/* >= YYNLSTATES means shift-and-reduce */
$rule = $state - $this->YYNLSTATES;
}
}
}
protected function getErrorMessage($symbol, $state) {
$expectedString = '';
if ($expected = $this->getExpectedTokens($state)) {
$expectedString = ', expecting ' . implode(' or ', $expected);
}
return 'Syntax error, unexpected ' . $this->symbolToName[$symbol] . $expectedString;
}
protected function getExpectedTokens($state) {
$expected = array();
@ -298,6 +372,14 @@ abstract class ParserAbstract
echo '% Reduce by (' . $n . ') ' . $this->productions[$n] . "\n";
}
protected function tracePop($state) {
echo '% Recovering, uncovered state ' . $state . "\n";
}
protected function traceDiscard($symbol) {
echo '% Discard ' . $this->symbolToName[$symbol] . "\n";
}
/*
* Helper functions invoked by semantic actions
*/