Re: [Exist-open] Handling variable number of parameters.

[Ron V. d. B. <ron...@ka...>]

Hi,

I think I have solved a similar problem: I wanted an extensible query 
form that could pass a theoretically indefinite number of search terms 
to my XQuery script (still before the XForms age, don't even know if 
this is why XForms was designed for). Those 'extensible' parameters have 
fixed names, suffixed with a counter, like "field1", "range1", "term1", 
"mode1", "scope1", "operator1". Each new form entry row will create an 
incremented set of these parameter names:  "field2", "range2", "term2", 
"mode2", "scope2", ... I tackled this problem as follows:
    1) Determine the total of the 'extensible' parameters, by counting 
how many times one of them occurs (using request:get-parameter-names()).   
    2) Get the parameter values with request:get-parameter(), by looping 
over the parameter names. The names for the parameters are computed by 
concatenating the parameter names with their respective ranking numbers.

  let $parCount := count(request:get-parameter-names()[starts-with(., 
'term')])
  let $formItems :=
      for $nr in 1 to $parCount
      return <query>{
        string-join(
           (request:get-parameter(concat("field", $nr), ""),
           request:get-parameter(concat("range", $nr), " "),
           request:get-parameter(concat("term", $nr), ""),
           request:get-parameter(concat("mode", $nr), ""),
           if (request:get-parameter(concat("scope", $nr), "")) then
             request:get-parameter(concat("scope", $nr), "")
           else '1',
           request:get-parameter(concat("operator", $nr), "")), "#_#")
      }</query>

The $formItems variable is then used further in the XQuery script to 
build the filtering predicate for my query expression.
[Note that the values are concatenated to a string, in order to avoid 
the construction of temporary fragments in a read-only database, when 
querying the $formItems variable further in the XQuery script.]

Kind regards,

Ron