Item10722: System.QuerySearch length() awkward for measuring lists

Recently I had a format string in a SEARCH that looked like this (links is a many type via registerMETA):

$percntQUERY{\"length('$web.$topic'/links[scope='external'].address\"}$percnt

Which worked fine, except for when there was only one external link on the topic - in that case, QUERY returned the length of the string. So I did this:

$percntQUERY{\"length(('$web.$topic'/links[scope='external'].address), '') - 1\"}$percnt

And that fixed my immediate problem. What I want to know is - do we document this behaviour and work-around - or is there a way to fix it? (I don't have any ideas how it can be fixed, without really geeking up the syntax to be even more painful than this work-around).

Also, I thought we had documented length(), but I can't find it in QuerySearch... if the doc is still missing, we should use this task to add it (and I guess any other undocumented ops/functions?)

-- PaulHarvey - 08 May 2011

I guess one way would be to add a strlen() and keep length() for lists.

-- PaulHarvey - 08 May 2011

Victim of perl's implicit polymorphism here. I originally intended "length" to apply only to strings, but clearly it works on arrays too. Where the parameter is an array, it should always be the length of the array, not the string in the array, so any implicit casting has to be handled.

• length(11,12,13) should be 3 is 3
• length 12 should be 2 is 2
• length (12) should be 1 is 2
• length '12' should be 2 is 2
• length((1,2)) should b1 1 is 2

(view using trunk!)

-- CrawfordCurrie - 21 May 2011

Hrm, I agree with all the examples except the last. Shouldn't length((1,2)) be measuring a list, and therefore return 2? I was under the impression that we were flattening lists in QuerySearch, according to my last understanding of QuerySearch doc

-- PaulHarvey - 22 May 2011

Fair point.

-- CrawfordCurrie - 22 May 2011

my 2cents.

I was trying this to do something like QUERY{length('Tasks.Item10722'/ImageList)+1}to increment an index value.

should be 1 is 1

This works on our version for zero length lists.

QUERY{length (%FORMFIELD{topic="Tasks.Item10722" "ImageList"}%) +1}should be 1 is 1

-- PaulAlexander - 05 Mar 2012

Hi Paul,

What about

%QUERY{
  "length(('%BASEWEB%.%BASETOPIC%'/ImageList)) + 1"
}%

-- PaulHarvey - 05 Mar 2012

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