I am working on a Wordpress site and recently I have begun getting this warning:
Warning: preg_match() [function.preg-match]: Unknown modifier '-'
It started when I changed the permalink structure to /%postname%/, which is needed for BuddyPress to function. If use the default permalink structure, the problem goes away.
Here is the code from the wp-includes/class-wp.php where the error is occurring:
if ( preg_match("#^$match#", $request_match, $matches) ||
preg_match("#^$match#", urldecode($request_match), $matches) ) {
this is because - and / are special symbols, you can change this code to:
if ( preg_match("/^".preg_quote($match)."/", $request_match, $matches) ||
preg_match("/^".preg_quote($match)."/", urldecode($request_match), $matches) ) {
but I assume that problem is somewhere deeper, in core logic of wp
Without the $match variable content it is difficult to know what the problem is, but if you obtain this warning, it's because $match contains #- (i.e. the pattern delimiter used and the - character). Then all characters after this # are seen as modifiers.
You can try to change the delimiter (and pray) to ~:
if ( preg_match("~^$match~", $request_match, $matches) ||
preg_match("~^$match~", urldecode($request_match), $matches) ) {
If it doesn't work try other delimiters.
Related
Cant understand this round bracket meaning.
Its not necessary to write it, but sometimes it can produce left-recursion error. Where should we use it in grammar rules?
Its not necessary to write it,
That is correct, it is not necessary. Just remove them.
but sometimes it can produce left-recursion error.
If that really is the case, you can open an issue here: https://github.com/antlr/antlr4/issues
EDIT
Seeing kaby76's comment, just to make sure: you cannot just remove them from a grammar file regardless. They can be removed from your example rule.
When used like this:
rule
: ID '=' ( NUMBER | STRING ) // match either `ID '=' NUMBER`
// or `ID '=' STRING`
;
they cannot be removed because removing them wold result in:
rule
: ID '=' NUMBER | STRING // match either `ID '=' NUMBER`
// or `STRING`
;
Or with repetition:
rule
: ( ID STRING )+ // match: `ID STRING ID STRING ID STRING ...`
;
and this:
rule
: ID STRING+ // match: `ID STRING STRING STRING ...`
;
Is there a way to parse words that start with a specific character?
I've been trying the following but i couldn't get any promising results:
//This one is working it accepts AD CD and such
example1
:
.'D'
;
//This one is not, it expects character D, then any ws character then any character
example2
:
'D'.
;
//These two are not working either
example3
:
'D'.*
;
//Doesn't accept input due to error: "line 1:3 missing 'D' at '<EOF>'"
example4
:
.*'D'
;
//just in case my WS rule:
/** WhiteSpace Characters (HIDDEN)*/
WS : ( ' '
| '\t'
)+ {$channel=HIDDEN;}
;
I am using ANTLR 3.4
Thanks in advance
//This one is not, it expects character D, then any ws character then any character
example2
:
'D'.
;
No, it does not it accept the token (not character!) 'D' followed by a space and then any character. Since example2 is a parser rule, it does not match characters, but matches tokens (there's a big difference!). And since you put spaces on a separate channel, the spaces are not matched by this rule either. At the end, the . (DOT) matches any token (again: not any character!).
More info on meta chars (like the . (DOT)) whose meaning differ inside lexer- and parser rules: Negating inside lexer- and parser rules
//These two are not working either
example3
:
'D'.*
;
//Doesn't accept input due to error: "line 1:3 missing 'D' at '<EOF>'"
example4
:
.*'D'
;
Unless you know exactly what you're doing, don't use .*: they gobble up too much in your case (especially when placed at the start or end of a rule).
It looks like you're trying to tokenize things inside the parser (all your example rules are parser rules). As far as I can see, these should be lexer rules instead. More on the difference between parser- and lexer rules, see: Practical difference between parser rules and lexer rules in ANTLR?
What I'm trying to do:
result = (not question?) \
and ( \
condition \
or ( \
comparer == compared and another_question? \
) \
)
The goal is to have complicated and / or logic and still have it be readable.
The problem with the above attempted syntax is that it some how messes up parenthesis in ruby's parser, so console says that the error is in a file that this code isn't in. (though it's in the call stack)
without the back slashes, I get these:
syntax error, unexpected kAND, expecting kEND (SyntaxError)
and
syntax error, unexpected kOR, expecting ')'
any ideas on how to properly do this?
Remove the space after the backslash in another_question? \. You're escaping the space rather than the newline, which causes a syntax error.
Note you don't need to escape every newline.
result = (not question?) \
and (
condition \
or (
comparer == compared and another_question?
)
)
For logical expression, you should use &&, ||, !, not and, or, not.
and, or, not should only be used for control-flow.
One reason is that &&, ||, ! have higher precedence than and, or, not.
Read more about this in this blog post.
Make sure each line (except the last) ends with an operator so the interpreter "knows" there will be more operands coming, e.g.
result = (not question?) and (
condition or
(comparer == compared and another_question?)
)
(tested with MRI 1.8.7)
Try this:
sub = (comparer == compared and another_question?)
result = (not question?) and (condition or sub)
No need to make the whole thing one expression.
in the sphinx changelog it says for 0.9.8:
"added query escaping support to query language, and EscapeString() API call"
can i assume, that there should be support for escaping special sphinx characters (#, !,
-, ...) for sphinxQL, too? if so, maybe someone could point me to an example on this. i'm
unable to find anything about it in the documentation or elsewhere on the net.
how do you do fulltext search (using spinxQL), if the search-phrase contains one of the special characters? i don't like the idea very much to "mask" them during indexing.
thanks!
The PHP version of the sphinxapi escape function did not work for me in tests. Also, it provides no protection against SQL-injection sorts of characters (e.g. single quote).
I needed this function:
function EscapeSphinxQL ( $string )
{
$from = array ( '\\', '(',')','|','-','!','#','~','"','&', '/', '^', '$', '=', "'", "\x00", "\n", "\r", "\x1a" );
$to = array ( '\\\\', '\\\(','\\\)','\\\|','\\\-','\\\!','\\\#','\\\~','\\\"', '\\\&', '\\\/', '\\\^', '\\\$', '\\\=', "\\'", "\\x00", "\\n", "\\r", "\\x1a" );
return str_replace ( $from, $to, $string );
}
Note the extra backslashes on the Sphinx-specific characters. I think what happens is that they put your whole query through an SQL parser, which removes escape backslashes 'extraneous' for SQL purposes (i.e. '\&' -> '&'). Then, it puts the MATCH clause through the fulltext parser, and suddenly '&' is a special character. So, you need the extra backslashes in the beginning.
There are corresponding functions EscapeString in each API ( php/python/java/ruby ) but to make escaping work with SphinxQL you have to write something similar in your application as SphinxQL hasn't such function.
The function itself is onliner
def EscapeString(self, string):
return re.sub(r"([=\(\)|\-!#~\"&/\\\^\$\=])", r"\\\1", string)
you could easy translate it to code of your application.
I need to be able to match a certain string ('[' then any number of equals signs or none then '['), then i need to match a matching close bracket (']' then the same number of equals signs then ']') after some other match rules. ((options{greedy=false;}:.)* if you must know). I have no clue how to do this in ANTLR, how can i do it?
An example: I need to match [===[whatever arbitrary text ]===] but not [===[whatever arbitrary text ]==].
I need to do it for an arbitrary number of equals signs as well, so therein lies the problem: how do i get it to match an equal number of equals signs in the open as in the close? The supplied parser rules so far dont seem to make sense as far as helping.
You can't easely write a lexer for it, you need parsing rules. Two rules should be sufficient. One is responsible for matching the braces, one for matching the equal signs.
Something like this:
braces : '[' ']'
| '[' equals ']'
;
equals : '=' equals '='
| '=' braces '='
;
This should cover the use case you described. Not absolute shure but maybe you have to use a predicate in the first rule of 'equals' to avoid ambiguous interpretations.
Edit:
It is hard to integrate your greedy rule and at the same time avoid a lexer context switch or something similar (hard in ANTLR). But if you are willing to integrate a little bit of java in your grammer you can write an lexer rule.
The following example grammar shows how:
grammar TestLexer;
SPECIAL : '[' { int counter = 0; } ('=' { counter++; } )+ '[' (options{greedy=false;}:.)* ']' ('=' { counter--; } )+ { if(counter != 0) throw new RecognitionException(input); } ']';
ID : ('a'..'z'|'A'..'Z'|'_') ('a'..'z'|'A'..'Z'|'0'..'9'|'_')*
;
WS : ( ' '
| '\t'
| '\r'
| '\n'
) {$channel=HIDDEN;}
;
rule : ID
| SPECIAL
;
Your tags mention lexing, but your question itself doesn't. What you're trying to do is non-regular, so I don't think it can be done as part of lexing (though I don't remember if ANTLR's lexer is strictly regular -- it's been a couple of years since I last used ANTLR).
What you describe should be possible in parsing, however. Here's the grammar for what you described:
thingy : LBRACKET middle RBRACKET;
middle : EQUAL middle EQUAL
| LBRACKET RBRACKET;