Referencing another Rule

[damodaranr]

I don't see how we can reference an already created rule/decision in a new decision so that we are not recreating the decision from scratch.
It would be nice if a condition can reference a pre existing condition. Is this possible now or could this be added.
A fact could allow picking another condition (decision) and automatically the possible values are True or False as it would be a type boolean.

[CacheControl]

Unless I'm misunderstanding, I think you should be able to achieve this by assigning the condition to a variable and using that variable when creating each rule.

[damodaranr]

Can I get an example of how this can be achieved using a json construct please?

[damodaranr]

Was thinking more on the lines of referencing the evaluation of a previously defined condition/event outcome in another rule so as to not restate the facts (Again idea being to having minimal js coding for the rules). See below example :
"decisions": [
{
"conditions": {
"any": [
{
"fact": "name",
"operator": "equal",
"value": "David"
},
{
"fact": "age",
"operator": "greaterThan",
"value": "21"
}
]
},
"event": {
"type": "DavidCanDrink",
}
},
{
"conditions": {
"all": [
{
"conditionRef": "DavidCanDrink",
"operator": "equal",
"value": "True"
},
{
"fact": "day",
"operator": "equal",
"value": "Monday"
}
]
},
"event": {
"type": "DavidMayDrink",
"params": {
"drinkName": "Martini"
}
}
}]

[chris-pardy]

@CacheControl Would it make sense to allow the creation of "facts" that used the condition format something like:

engine.addFact({
   "name": "DavidCanDrink",
   "conditions": {
       "all": [
         {
            "fact": "name",
            "operator":"equal",
            "value": "David"
          },
          {
            "fact": "age",
             "operator": "greaterThanInclusive",
             "value": 21
          }
       ]
   }
});

engine.addRule({
  "conditions": {
    "all": [
      {
        "fact": "DavidCanDrink",
        "operator": "equal",
        "value": true
       },
       {
         "fact": "day",
         "operator": "equal",
         "value": "Monday",
    ]
  },
  "event": {
     "type": "DavidMayDrink",
      "params": {
        "drinkName": "Martini"
      }
  } 
});

This could allow Facts to be defined by users and loaded into the system at run-time. The requirement would be that the fact would have to be a boolean value.
I'm thinking you could even introduce a syntax similar to the { "fact": "name" } one used in the value field where you could reference a parameter. Something like: { "param": "name" } which would then require the new fact to have a name field in the params.

Rewriting the above rule you could do something like:

engine.addFact({
   "name": "CanDrink",
   "conditions": {
       "all": [
         {
            "fact": "name",
            "operator":"equal",
            "value": { "param": "name" }
          },
          {
            "fact": "age",
             "operator": "greaterThanInclusive",
             "value": 21
          }
       ]
   }
});

engine.addRule({
  "conditions": {
    "all": [
      {
        "fact": "CanDrink",
        "operator": "equal",
        "value": true,
        "params": {
          "name": "David"
        }
       },
       {
         "fact": "day",
         "operator": "equal",
         "value": "Monday",
    ]
  },
  "event": {
     "type": "DavidMayDrink",
      "params": {
        "drinkName": "Martini"
      }
  } 
});