comparing fomula

Anyone know of a foundry utility to compare two strings that might be dice formulae to tell which has the lesser deterministic value?

🧵

use case:
I have two strings that
- might just be numbers ('3' and '4')
- might be simple formula ('3 + 3' and '4')
- might be nonDeterministic formula ('3 + 1d4' and '4')

I want to know:
- if both are deterministic formula, what is the Floor of their values
- if they aren't deterministic, I'll do nothing with either value

oh i can use dnd5e's simplifyRollFormula for this

if the output of simplifyRollFormula is parsable as a Number, I can compare them easily

ok wtf js

oh, i'm dumb. .floor is for rounding
I'm looking for .min

this is definitely excessive...

    const { abilities, attributes, bonuses, details } = this.actor.system;

    let spellAttackModFormula = [
      new Intl.NumberFormat('en-US', {
        signDisplay: 'exceptZero',
      })
        .format((abilities[attributes.spellcasting || 'int']?.mod ?? 0) + attributes.prof)
        .toString(),
    ];

    // apply the bonuses if they are equivalent
    if (bonuses.msak.attack === bonuses.rsak.attack) {
      spellAttackModFormula.push(bonuses.msak.attack);
      // apply the lesser deterministic bonus
    } else if (!!bonuses.msak.attack && !!bonuses.rsak.attack) {
      const lesserBonus = Math.min(
        dnd5e.dice.simplifyRollFormula(bonuses.msak.attack),
        dnd5e.dice.simplifyRollFormula(bonuses.rsak.attack)
      );

      // if lesserBonus is a number, push it to the spellAttackModFormula
      if (!Number.isNaN(lesserBonus)) {
        spellAttackModFormula.push(lesserBonus);
      }
    }
    sheetData.spellAttackMod =
      spellAttackModFormula.length === 1
        ? spellAttackModFormula[0]
        : dnd5e.dice.simplifyRollFormula(spellAttackModFormula.join(' + '));

BUT
it does do what I was looking for and covers all the edge cases I can think of

Most of the time I know of, if there's a bonus, it'll be adding to both msak and rsak to represent a global increase

but the data does support disparate mods, in which case, applying the lesser one is 'safe' to this display of 'spell attack modifier'

.evaluate({min:true, async:false}) doesn't work for you?

Or did I misunderstand what you were after?

is that a method on Roll?

Yes.

min would return the minimum possible based on the formula provided?

Yes. It sets the dice to minimum value they'd give instead of randomizing them and returns the result.

gotcha, not quite what i'm looking for

I'm really looking to compare two formulas, and use the 'min' one

(but only if they're deterministic)

Roll.isDeterministic is a thing

It also exists for individual terms.

That is available pre-eval

so the alternative to using the dnd5e simplifyRollFormula would look something like :

const formulaA = new Roll(bonuses.msak.attack);
const formulaB = new Roll(bonuses.rsak.attack);

if (formulaA.isDeterministic() && formulaB.isDeterministic()) {
  spellAttackModFormula.push(
    Math.min(formulaA.evaluate(), formulaB.evaluate());
  );
}

Almost, .isDeterministic is a getter.
And .evaluate() returns Roll instance, so you'd need to add .total there.

Also eval is async unless you tell it to be non-async.

that async:false is being deprecated right?

I could probably DIY that actually if isDeterministic is true jk not as easy i expected in js

People keep saying it's not. The requirement for it is, because async is becoming the default.

And there's no warning in it that sync option is going away, just that it won't be the default.

goootcha

Anyway, you'd have this:

if (formulaA.isDeterministic && formulaB.isDeterministic) {
  spellAttackModFormula.push(
    Math.min(formulaA.evaluate({async:false}).total, formulaB.evaluate({async:false}.total));
  );
}

so then the question i have is 'is the overhead of creating two Rolls to compare these strings greater than or less than using simplifyRollFormula?'

odds are, less than, simplifyRollFormula is a heavy function now that I look closer

I'd favor whichever makes the intent of the code clearer.

    // apply the bonuses if they are equivalent
    if (bonuses.msak.attack === bonuses.rsak.attack) {
      spellAttackModFormula.push(bonuses.msak.attack);
    } else if (!!bonuses.msak.attack && !!bonuses.rsak.attack) {
      const formulaA = new Roll(bonuses.msak.attack);
      const formulaB = new Roll(bonuses.rsak.attack);

      // apply the lesser deterministic bonus
      if (formulaA.isDeterministic && formulaB.isDeterministic) {
        spellAttackModFormula.push(
          Math.min(formulaA.evaluate({ async: false }).total, formulaB.evaluate({ async: false }.total))
        );
      }
    }

suspect this will never be clear 😛 but this is a solidly simpler solution and doesn't rely on 5e code

thanks @Mana

@Calego gave LeaguePoints™ to @Mana (#15 • 203)

🎉

External constraint, could be a simple formula like "+1 +1 +2"