Using the debugger I saw that the expected strings were handed over to
the function. If you use '\\3' at the SQL level, the C string that
the C function gets is "\\3" (in C syntax).
Sjoerd Mullender
On 08/10/15 12:24, Stefan Manegold wrote:
>
>
> ... or maybe just their rendering in the TRACE is wrong ... ?
>
> ----- On Oct 8, 2015, at 12:22 PM, Stefan Manegold
> Stefan.Manegold@cwi.nl wrote:
>
>> Hi,
>>
>> mainly for the developer(s) who might look into this:
>>
>> even if we (i.e., our pcre.replace() function supports the back
>> references, at least the backslash passing from the query string
>> to the MAL call is not up to the task; single backslashes
>> disappear, double backslashes remain double; cf.,
>>
>> sql>trace select pcre_replace('15/10/2015',
>> '^(3[01]|[12][0-9]|0?[1-9])/(1[012]|0?[1-9])/([0-9]{4})$',
>> '\3-\2-\1', 'i'); +---------------------------+ |
>> pcre_replace_single_value | +===========================+ | 3-2-1
>> | +---------------------------+ 1 tuple (2.474ms)
>> +-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
>>
>>
| ticks | statement
>> | |
>> +=======+=====================================================================================================================================================================================================+
>>
>>
| 0 | X_13=0@0:void := querylog.define("select
pcre_replace(\\'15/10/2015\\',
>> |
>> \\'^(3[01]|[12][0-9]|0?[1-9])/(1[012]|0?[1-9])/([0-9]{4})$\\', |
>> \\'{3}-{2}-{1}\\', \\'i\\');":str,"default_pipe":str,5:int); | |
>> 37 | X_6="3-2-1":str := |
>> pcre.replace(A0="15/10/2015":str,A1="^(3[01]|[12][0-9]|0?[1-9])/(1[012]|0?[1-9])/([0-9]{4})$":str,A2="3-2-1":str,A3="i":str);
>>
>>
| |
>> | 9 | |
>> sql.resultSet(".L":str,"pcre_replace_single_value":str,"clob":str,0:int,0:int,4:int,X_6="3-2-1":str);
>>
>>
| |
>> | 1 | end user.s4_1; | | | 527 | function
>> user.s4_1{autoCommit=true}(A0:str,A1:str,A2:str,A3:str):void; |
>> | | 596 | X_4=0@0:void := |
>> user.s4_1("15/10/2015":str,"^(3[01]|[12][0-9]|0?[1-9])/(1[012]|0?[1-9])/([0-9]{4})$":str,"3-2-1":str,"i":str);
>>
>>
| |
>> +-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
>>
>>
6 tuples (2.578ms)
>>
>> sql>trace select pcre_replace('15/10/2015',
>> '^(3[01]|[12][0-9]|0?[1-9])/(1[012]|0?[1-9])/([0-9]{4})$',
>> '\\3-\\2-\\1', 'i'); +---------------------------+ |
>> pcre_replace_single_value | +===========================+ |
>> \3-\2-\1 | +---------------------------+ 1 tuple
>> (59.813ms)
>> +-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
>>
>>
| ticks | statement
>> | |
>> +=======+=====================================================================================================================================================================================================+
>>
>>
| 2 | X_13=0@0:void := querylog.define("select
pcre_replace(\\'15/10/2015\\',
>> |
>> \\'^(3[01]|[12][0-9]|0?[1-9])/(1[012]|0?[1-9])/([0-9]{4})$\\', |
>> \\'{3}-{2}-{1}\\', \\'i\\');":str,"default_pipe":str,5:int); | |
>> 38 | X_6="\\3-\\2-\\1":str := |
>> pcre.replace(A0="15/10/2015":str,A1="^(3[01]|[12][0-9]|0?[1-9])/(1[012]|0?[1-9])/([0-9]{4})$":str,A2="\\3-\\2-\\1":str,A3="i":str);
>>
>>
| |
>> | 10 | |
>> sql.resultSet(".L":str,"pcre_replace_single_value":str,"clob":str,0:int,0:int,4:int,X_6="\\3-\\2-\\1":str);
>>
>>
| |
>> | 1 | end user.s4_1; | | | 592 | function
>> user.s4_1{autoCommit=true}(A0:str,A1:str,A2:str,A3:str):void; |
>> | | 670 | X_4=0@0:void := |
>> user.s4_1("15/10/2015":str,"^(3[01]|[12][0-9]|0?[1-9])/(1[012]|0?[1-9])/([0-9]{4})$":str,"\\3-\\2-\\1":str,"i":str);
>>
>>
| |
>> +-------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
>>
>>
6 tuples (59.928ms)
>>
>> Best, Stefan
>>
>> ----- On Oct 8, 2015, at 12:00 PM, imad hajj chahine
>> imad.hajj.chahine@gmail.com wrote:
>>
>>> Hi,
>>>
>>> Monetdb is using pcre library for regular expression support,
>>> and using this function we can allow SQL to use the regex
>>> library:
>>>
>>> CREATE FUNCTION "pcre_replace" (origin string, pat string, repl
>>> string, flags string) RETURNS string EXTERNAL NAME
>>> pcre."replace";
>>>
>>>
>>> I want to use regex for date conversion to the format supported
>>> by monetdb (yyyy-MM-dd), I have the following format
>>> dd/MM/yyyy, and i am trying to run the following with no
>>> success:
>>>
>>> select pcre_replace('15/10/2015',
>>> '^(3[01]|[12][0-9]|0?[1-9])/(1[012]|0?[1-9])/([0-9]{4})$',
>>> '\\3-\\2-\\1', 'i')
>>>
>>> select pcre_replace('15/10/2015',
>>> '^(3[01]|[12][0-9]|0?[1-9])/(1[012]|0?[1-9])/([0-9]{4})$',
>>> '{3}-{2}-{1}', 'i')
>>>
>>> select pcre_replace('15/10/2015',
>>> '^(?<day>3[01]|[12][0-9]|0?[1-9])/(?<month>1[012]|0?[1-9])/(?<year>[0-9]{4})$',
>>>
>>>
'\\k<year>-\\k<month>-\\k<day>', 'i')
>>>
>>>
>>> My question is, is backreference supported in the replacement
>>> string; if yes, whats is the right syntax to use to reference
>>> the detected groups, if no, is there a clever way then using
>>> substring?
>>>
>>> Thanks
>>>
>>>
>>> _______________________________________________ users-list
>>> mailing list users-list@monetdb.org
>>> https://www.monetdb.org/mailman/listinfo/users-list
>>
>> -- | Stefan.Manegold@CWI.nl | DB Architectures (DA) | |
>> www.CWI.nl/~manegold/ | Science Park 123 (L321) | | +31 (0)20
>> 592-4212 | 1098 XG Amsterdam (NL) |
>> _______________________________________________ users-list
>> mailing list users-list@monetdb.org
>> https://www.monetdb.org/mailman/listinfo/users-list
>
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