At 2010-03-24 08:53 -0500, Strawn, M. Shane wrote:
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In v3, fn:tokenize would do this:
fn:tokenize("word", "") ==> ("w", "o", "r", "d")
Â…but in v4 that returns an error:
[1.0-ml] XDMP-MATCHZERO: (err:FORX0003)
fn:tokenize("word", "") -- Pattern matches zero-length string
With the 2nd param interpreted as a reg-ex
pattern, I'm not sure why it ever worked, but it was handy.
Any comments on why this is the case?
It is specified to do so ... from 7.6.4 fn:tokenize:
If the supplied $pattern matches a zero-length string,
that is, if fn:matches("", $pattern, $flags) returns
true, then an error is raised: [err:FORX0003].
I'm guessing because there would be an infinite
number of occurrences of an empty string
in-between two characters before "moving" to the
next character in the search for non-matching substrings.
How's this on speed/efficiency for replicating
it? Not that I know how fast the tokenize version was.
Nor do I ... but anything accomplished by the
processor would be faster than anything coded by
hand (modulo any optimization and rewriting done
by the processor). So the objective would be to
find a written algorithm that would compare well to other written algorithms.
for $pos in 1 to fn:string-length("word") return
fn:substring("word", $pos, 1) ==> ("w", "o", "r", "d")
I think the following might be faster because you
won't be indexing into the entire input string
once for each character in the string, yet it is
using the same number of function invocations:
T:\ftemp>type shane.xq
for $each in string-to-codepoints( "word" )
return codepoints-to-string( $each )
T:\ftemp>xquery shane.xq
<?xml version="1.0" encoding="UTF-8"?>w o r d
T:\ftemp>
I hope this helps.
. . . . . . . . . . . . Ken
--
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