Multiple property Select in microsoft RulesEngine expression

Question

I am researching some rule engines and I came across Microsoft RulesEngine: https://microsoft.github.io/RulesEngine/. It looks verry promising, because I get a lot of flexibility in the rules and the inputs. However I encountered some problems when tried to do a Select/Projection to a extending expression custom class/type.

Here is the scenario. Given the input:

"reportId": "r1",
"reportVersionId": 2,
"defects": [
  {
    "id": "d1",
    "isMerging": true,
    "mergeDefectId": "d2",
    "state": "open",
    "defectStartPoint": 2,
    "defectEndPoint": 10
  },
  {
    "id": "d2",
    "isMerging": true,
    "state": "close",
    "defectStartPoint": 8,
    "defectEndPoint": 15
  },
  {
    "id": "d3",
    "isMerging": false,
    "state": "open",
    "defectStartPoint": 1,
    "defectEndPoint": 5
  }
]

I want to perform some more complex checks on this list (just an example: if one of the defects have "status":"open" and "isMerging": true, check if the MergingDefectId is a valid id (another defect with that id exists and that defect is valid)). So based on this: https://microsoft.github.io/RulesEngine/#extending-expression-via-custom-classtype-injection I created this class:

public static class ComplexRulesMethods
{
    public static bool IsValid(object input)
    {
        //Perform complex logic
        return true;
    }
}

And for the rule file I have:

[
  {
    "WorkflowName": "workflowName",
    "Rules": [
      {
        "RuleName": "ruleName",
        "ErrorMessage": "errorMessage",
        "ErrorType": "Error",
        "RuleExpressionType": "LambdaExpression",
        "Expression": "ComplexRulesMethods.IsValid(input1.currentVersion.defects.Select( new {id as id, isMerging as isMerging, mergeDefectId as mergeDefectId} ))"

      }
    ]
  }
]

The plan is to make IsValid(object input) generic, so it will be able to validate a list of objects with "id","isMerging" and "mergedDefectId" properties. Doing this if I get another input on which I can do this validation, I will just create another expression and map the new input fields to those 3 ("id","isMerging" and "mergedDefectId").

The problem is that whenever I want to perform the select with multiple properties ( "Expression": "ComplexRulesMethods.IsValid(input1.defects.Select(id))" works fine), I get this error: Exception while parsing expression ComplexRulesMethods.IsValid(input1.defects.Select( new {id as id, isMerging as isMerging, mergeDefectId as mergeDefectId} )) - No property or field 'id' exists in type 'Boolean'.

I tried multiple variants using () instead of {}, with and without 'it.', but I always get that error, and I don't know exactly why, and if what I want is actually possible.

Answer 1

I think you need to use ( ) instead of { }.

So like thisp:

"ComplexRulesMethods.IsValid(input1.currentVersion.defects.Select( new (id as id, isMerging as isMerging, mergeDefectId as mergeDefectId) ))"

See also this link on the GitHub project page.