$getSharedParamValue

Reads a numeric shared parameter from an object. Returns the value as a number, or null if the parameter is absent or has no value.

---

Definition

$getSharedParamValue := function($object, $logicalName){
  (
    $guid := $lookup($paramGuids, $logicalName);
    $sp   := $guid and $exists($object.values)
              ? $lookup($object.values, "p_" & $guid)
              : undefined;

    $exists($sp.value)
      ? $number($sp.value)
      : null
  )
};

---

Dependencies

Requires $paramGuids in the outer scope:

$paramGuids := {
  "NLRS_C_weerstandsklasse": "8f1f7e7c-a1c6-46ba-89bf-c28af15d5783"
};

---

Parameters

Parameter	Type	Description
$object	object	The element to read from (pass $ for current element)
$logicalName	string	The key in $paramGuids

---

Return value

Situation	Returns
Parameter exists with value	3 (number)
Parameter exists, no value	null
Parameter absent	null

---

Why $number() is used

Revit may store numeric parameter values as strings. $number() ensures the output field is a proper JSON number, which matters when the validator uses int:LessThan, int:GreaterThan, or int:EqualTo.

---

Usage

$[type = "FamilyInstance" and $exists(parent)].{
  "id": id,
  "name": name,
  "NLRS_C_weerstandsklasse": $getSharedParamValue($, "NLRS_C_weerstandsklasse")
}

Validator: NLRS_C_weerstandsklasse → list:IsIn [1, 2, 3, 4, 5, 6]

---

Used in rules

• rule-b5262621 — NLRS_C_weerstandsklasse is een geldige waarde