Assignment to local variables in Expression rule

RE: Assignment to local variables in Expression rule

Vasudeva — Tue, 04 Jul 2023 07:39:44 GMT

thank you will go through it... really this is a wonderful community 🙂

RE: Assignment to local variables in Expression rule

Mathieu Drouin — Mon, 03 Jul 2023 23:52:51 GMT

The local variables section pretty much covers it.

docs.appian.com/.../Local_Variables.html

RE: Assignment to local variables in Expression rule

Vasudeva — Mon, 03 Jul 2023 21:50:46 GMT

Where can I find more info on this, I have tried the expression section of the Appian documentation, but I couldn't find any thing, I'm looking for examples and howtos..

I have referred to this -> docs.appian.com/.../Expressions.html

RE: Assignment to local variables in Expression rule

Mike Schmitt — Mon, 03 Jul 2023 20:56:03 GMT

basically, yes.

RE: Assignment to local variables in Expression rule

Vasudeva — Mon, 03 Jul 2023 20:55:22 GMT

ok, so the rule of thumb is to initialize the local variable during declaration it self. Got it, thanks 🙂

RE: Assignment to local variables in Expression rule

Mike Schmitt — Mon, 03 Jul 2023 20:48:31 GMT

[quote userid="120503" url="~/discussions/f/new-to-appian/29200/assignment-to-local-variables-in-expression-rule/115496#115496"]the value would come after initialization as a result of some equation [/quote]

You would declare its value after any other calculations (usually declared as their own local variables) on which it depends.

RE: Assignment to local variables in Expression rule

Vasudeva — Mon, 03 Jul 2023 20:47:01 GMT

Thanks Mike for your input.

If you know its initial value, then you will assign it at creation time. -- what if I don't know the value of the variable during initialization and the value would come after initialization as a result of some equation like we do in traditional programming. how to handle such scenarios.

RE: Assignment to local variables in Expression rule

Mathieu Drouin — Mon, 03 Jul 2023 20:45:39 GMT

I think maybe having that variable being the key in the dictionary might be doing weird things.

Try this:

a!localVariables(
  local!parts: {
    a!map(
      partName: "part1",
      quantity: 1,
      unitCost: 1
    ),
    a!map(
      partName: "part2",
      quantity: 1,
      unitCost: 1
    )

  },
  {
    parts: local!parts,
    length: length(local!parts)
  }
)

RE: Assignment to local variables in Expression rule

Mike Schmitt — Mon, 03 Jul 2023 20:41:21 GMT

There are mainly only 2 places where you can "assign a value" to a local variable:

1) at declaration

2) as the result of a user interaction in an interface component

Seeing as this is an expression rule, and therefore #2 is irrelevant, you will need to assign the value at declaration (#1).

This is the most important concept here: There is no such thing, in Appian's expression language, as "define a blank local variable then in a later line of code give it a new value". If you know its initial value, then you will assign it at creation time.