Hi,
On 2011.05.18 23:11, Ron Pinkas wrote:
>> ? len( hb_aTokens( "" , "|" ) )
>> ? len( hb_aTokens( "|" , "|" ) )
>> ? len( hb_aTokens( "||" , "|" ) )
>>
>> do you find above results natural?
>
> Sorry I really don't understand. I expect 0, 2, 3 or 0,1,2 depending on
> whether terminator delimiter is expected or not (IMO there should be an
> additional argument to control such behavior). What results would you
> expect, and more importantly WHY?
I would expect return 1, 2, 3. Also, I would expect natural:
hb_aTokens( "" , "|" ) -> {""}
hb_aTokens( "a" , "|" ) -> {"a"}
hb_aTokens( "|a" , "|" ) -> {"", "a"}
hb_aTokens( "a|" , "|" ) -> {"a", ""}
hb_aTokens( "a|b" , "|" ) -> {"a", "b"}
without an exception for empty string.
Why? Because I expect
hb_atokens(string+delimiter+token, delimiter)
should return array like
hb_atokens(string, delimiter)
but with additional token in the end.
If that is true, and
hb_atoken("|a", "|")
returns
{"", "a"}
then
hb_atoken("", "|")
should return
{""}
This is simple to prove by replacing string="", token="a", and
delimiter="|".
I would also expect no additional parameter for "feature tuning",
because it only makes function behaviour not clean. F.e., what is
expected function return value if parameter indicates that termination
delimiter should be included, but there is no terminating delimiter in
the end of string? Should hb_atokens("a|b", "|", .T.) return {"a"}? BTW,
this common situation in parsing text files.
>> Please note that now it's not possible to serialize (convert to text) such
>> array
>> { "" }
>> so later it can be restored from string by hb_aTokens() function.
>
> Sorry, I don't understand why? What logic do you use to de-serialize such
> array?
I guess Przemek is talking about
FUNC funcname( aTokens, cDelimiter )
LOCAL cString := ""
FOR nI := 1 TO LEN(aTokens)
cString += IIF(nI == 1, "", cDelimiter) + aTokens[nI]
NEXT
RETURN cString
Without empty string exception, hb_atokens() and the function above has
1:1 correspondence for all not empty arrays of strings (assuming strings
does not contain delimiter). That's a nice fact. With empty string
exception the property above is not valid.
I'm just happy we do not have such discussion on Harbour mailing list!
Regards,
Mindaugas
P.S. BTW, do we have function in [x]Harbour that returns a delimited
string from a string array? I find
hb_memowrit("file.txt", funcname(aLines, CHR(10)))
as much useful as
aLines := hb_atokens(hb_memoread("file.txt"), CHR(10))
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