*/
// Complain about martian char.
-function lexError1 ($state, $text, $pos)
+function lexError1 ($state, $text, $pos, $ln = 'N/A')
{
- $message = "invalid char with code " . ord (mb_substr ($text, $pos, 1)) . ' (';
- $message .= mb_substr ($text, $pos, 1) . ") at position ${pos} (FSM state is '${state}')";
- return array ('result' => 'NAK', 'load' => $message);
+ return array
+ (
+ 'result' => 'NAK',
+ 'load' => "Invalid character '" . mb_substr ($text, $pos, 1) . "' near line ${ln}"
+ );
}
// Complain about martian keyword.
-function lexError2 ($word)
+function lexError2 ($word, $ln = 'N/A')
{
return array
(
'result' => 'NAK',
- 'load' => "could not parse keyword '${word}'"
+ 'load' => "Invalid keyword '${word}' near line ${ln}"
);
}
// Complain about wrong FSM state.
-function lexError3 ($state)
+function lexError3 ($state, $ln = 'N/A')
{
return array
(
'result' => 'NAK',
- 'load' => "FSM state is still '${state}' at end of input"
+ 'load' => "Lexical error during '${state}' near line ${ln}"
);
}
-function lexError4 ($s)
+function lexError4 ($s, $ln = 'N/A')
{
return array
(
'result' => 'NAK',
- 'load' => "Invalid tag or predicate name '${s}'"
+ 'load' => "Invalid name '${s}' near line ${ln}"
);
}
{
$ret = array();
$textlen = mb_strlen ($text);
+ $lineno = 1;
$state = "ESOTSM";
for ($i = 0; $i < $textlen; $i++) :
$char = mb_substr ($text, $i, 1);
switch (TRUE)
{
case ($char == '('):
- $ret[] = array ('type' => 'LEX_LBRACE');
+ $ret[] = array ('type' => 'LEX_LBRACE', 'lineno' => $lineno);
break;
case ($char == ')'):
- $ret[] = array ('type' => 'LEX_RBRACE');
+ $ret[] = array ('type' => 'LEX_RBRACE', 'lineno' => $lineno);
break;
case ($char == '#'):
$newstate = 'skipping comment';
$newstate = 'reading keyword';
$buffer = $char;
break;
- case (preg_match ('/^[ \t\n\r]$/', $char)):
+ case ($char == "\r"): // FIXME: this should never happen
+ case ($char == "\n"):
+ $lineno++; // fall through
+ case ($char == " "):
+ case ($char == "\t"):
// nom-nom...
break;
case ($char == '{'):
$newstate = 'reading predicate 1';
break;
default:
- return lexError1 ($state, $text, $i);
+ return lexError1 ($state, $text, $i, $lineno);
}
break;
case 'reading keyword':
case (mb_ereg ('[[:alpha:]]', $char) > 0):
$buffer .= $char;
break;
- case (preg_match ('/^[ \t\n]$/', $char)):
+ case ($char == "\n"):
+ $lineno++; // fall through
+ case ($char == " "):
+ case ($char == "\t"):
// got a word, sort it out
switch ($buffer)
{
case 'allow':
case 'deny':
- $ret[] = array ('type' => 'LEX_DECISION', 'load' => $buffer);
+ $ret[] = array ('type' => 'LEX_DECISION', 'load' => $buffer, 'lineno' => $lineno);
break;
case 'define':
- $ret[] = array ('type' => 'LEX_DEFINE');
+ $ret[] = array ('type' => 'LEX_DEFINE', 'lineno' => $lineno);
break;
case 'and':
case 'or':
- $ret[] = array ('type' => 'LEX_BOOLOP', 'load' => $buffer);
+ $ret[] = array ('type' => 'LEX_BOOLOP', 'load' => $buffer, 'lineno' => $lineno);
break;
case 'not':
- $ret[] = array ('type' => 'LEX_NOT');
+ $ret[] = array ('type' => 'LEX_NOT', 'lineno' => $lineno);
break;
case 'false':
case 'true':
- $ret[] = array ('type' => 'LEX_BOOLCONST', 'load' => $buffer);
+ $ret[] = array ('type' => 'LEX_BOOLCONST', 'load' => $buffer, 'lineno' => $lineno);
break;
default:
- return lexError2 ($buffer);
+ return lexError2 ($buffer, $lineno);
}
$newstate = 'ESOTSM';
break;
default:
- return lexError1 ($state, $text, $i);
+ return lexError1 ($state, $text, $i, $lineno);
}
break;
case 'reading tag 1':
switch (TRUE)
{
- case (preg_match ('/^[ \t\n\r]$/', $char)):
+ case ($char == "\n"):
+ case ($char == "\r"): // FIXME: is this really expected?
+ $lineno++; // fall through
+ case ($char == " "):
+ case ($char == "\t"):
// nom-nom...
break;
case (mb_ereg ('[[:alnum:]\$]', $char) > 0):
$newstate = 'reading tag 2';
break;
default:
- return lexError1 ($state, $text, $i);
+ return lexError1 ($state, $text, $i, $lineno);
}
break;
case 'reading tag 2':
case ($char == '}'):
$buffer = rtrim ($buffer);
if (!validTagName ($buffer, TRUE))
- return lexError4 ($buffer);
- $ret[] = array ('type' => 'LEX_TAG', 'load' => $buffer);
+ return lexError4 ($buffer, $lineno);
+ $ret[] = array ('type' => 'LEX_TAG', 'load' => $buffer, 'lineno' => $lineno);
$newstate = 'ESOTSM';
break;
case (mb_ereg ('[[:alnum:]\. _~-]', $char) > 0):
$buffer .= $char;
break;
default:
- return lexError1 ($state, $text, $i);
+ return lexError1 ($state, $text, $i, $lineno);
}
break;
case 'reading predicate 1':
$newstate = 'reading predicate 2';
break;
default:
- return lexError1 ($state, $text, $i);
+ return lexError1 ($state, $text, $i, $lineno);
}
break;
case 'reading predicate 2':
case ($char == ']'):
$buffer = rtrim ($buffer);
if (!validTagName ($buffer))
- return lexError4 ($buffer);
- $ret[] = array ('type' => 'LEX_PREDICATE', 'load' => $buffer);
+ return lexError4 ($buffer, $lineno);
+ $ret[] = array ('type' => 'LEX_PREDICATE', 'load' => $buffer, 'lineno' => $lineno);
$newstate = 'ESOTSM';
break;
case (mb_ereg ('[[:alnum:]\. _~-]', $char) > 0):
$buffer .= $char;
break;
default:
- return lexError1 ($state, $text, $i);
+ return lexError1 ($state, $text, $i, $lineno);
}
break;
case 'skipping comment':
switch ($char)
{
case "\n":
+ $lineno++;
$newstate = 'ESOTSM';
default: // eat char, nom-nom...
break;
$state = $newstate;
endfor;
if ($state != 'ESOTSM' and $state != 'skipping comment')
- return lexError3 ($state);
+ return lexError3 ($state, $lineno);
return array ('result' => 'ACK', 'load' => $ret);
}
// LEX_TAG
// LEX_PREDICATE
// LEX_BOOLCONST
-// SYNT_NOT (1 argument, holding SYNT_EXPR)
+// SYNT_NOTEXPR (1 argument, holding SYNT_EXPR)
// SYNT_BOOLOP (2 arguments, each holding SYNT_EXPR)
// SYNT_DEFINITION (2 arguments: term and definition)
// SYNT_GRANT (2 arguments: decision and condition)
// Perform shift-reduce processing. The "accept" actions occurs with an
// empty input tape and the stack holding only one symbol (the start
- // symbol, SYNT_CODETEXT).
+ // symbol, SYNT_CODETEXT). When reducing, set the "line number" of
+ // the reduction result to the line number of the "latest" item of the
+ // reduction base (the one on the stack top). This will help locating
+ // parse errors, if any.
while (TRUE)
{
$stacktop = $stacksecondtop = $stackthirdtop = array ('type' => 'null');
$stacksecondtop['type'] == 'LEX_DEFINE'
)
{
+ // reduce!
array_pop ($stack);
array_pop ($stack);
array_push
array
(
'type' => 'SYNT_DEFINE',
+ 'lineno' => $stacktop['lineno'],
'load' => $stacktop['load']
)
);
array
(
'type' => 'SYNT_EXPR',
+ 'lineno' => $stacktop['lineno'],
'load' => $stacktop
)
);
array
(
'type' => 'SYNT_EXPR',
+ 'lineno' => $stacktop['lineno'],
'load' => array
(
'type' => 'SYNT_NOTEXPR',
array_pop ($stack);
array_pop ($stack);
array_pop ($stack);
+ $stacksecondtop['lineno'] = $stacktop['lineno'];
array_push
(
$stack,
array
(
'type' => 'SYNT_EXPR',
+ 'lineno' => $stacktop['lineno'],
'load' => array
(
'type' => 'SYNT_BOOLOP',
array
(
'type' => 'SYNT_GRANT',
+ 'lineno' => $stacktop['lineno'],
'decision' => $stacksecondtop['load'],
'condition' => $stacktop['load']
)
array
(
'type' => 'SYNT_DEFINITION',
+ 'lineno' => $stacktop['lineno'],
'term' => $stacksecondtop['load'],
'definition' => $stacktop['load']
)
array_pop ($stack);
array_pop ($stack);
$stacksecondtop['load'][] = $stacktop;
+ $stacksecondtop['lineno'] = $stacktop['lineno'];
array_push
(
$stack,
array
(
'type' => 'SYNT_CODETEXT',
+ 'lineno' => $stacktop['lineno'],
'load' => array ($stacktop)
)
);
// The moment of truth.
if (count ($stack) == 1 and $stack[0]['type'] == 'SYNT_CODETEXT')
return array ('result' => 'ACK', 'load' => $stack[0]['load']);
- return array ('result' => 'NAK', 'load' => 'Syntax error!');
+ // No luck. Prepare to complain.
+ if ($lineno = locateSyntaxError ($stack))
+ return array ('result' => 'NAK', 'load' => 'Syntax error near line ' . $lineno);
+ // HCF
+ return array ('result' => 'NAK', 'load' => 'Syntax error: empty text');
}
}
return array ('result' => 'ACK', 'load' => $code);
}
+// Accept a stack and figure out the cause of it not being parsed into a tree.
+// Return the line number or zero.
+function locateSyntaxError ($stack)
+{
+ // The first SYNT_CODETEXT node, if is present, holds stuff already
+ // successfully processed. Its line counter shows, where the last reduction
+ // took place (it _might_ be the same line, which causes the syntax error).
+ // The next node (it's very likely to exist) should have its line counter
+ // pointing to the place, where the first (of 1 or more) error is located.
+ if (isset ($stack[0]['type']) and $stack[0]['type'] == 'SYNT_CODETEXT')
+ unset ($stack[0]);
+ foreach ($stack as $node)
+ // Satisfy with the first line number met.
+ if (isset ($node['lineno']))
+ return $node['lineno'];
+ return 0;
+}
+
?>
projects / racktables / commitdiff
