Slight refactor of calculate_dice_amount. Lazy error handling.

Use unwrap_or_else instead of unwrap_or to prevent unnecessary error
string creation. Also some changes to make the code a bit more
readable.
This commit is contained in:
projectmoon 2021-02-02 22:02:43 +00:00
parent 7512ca0694
commit f5a8e16ce0
1 changed files with 9 additions and 8 deletions

View File

@ -6,26 +6,27 @@ use crate::parser::Amount;
use crate::parser::Element as NewElement;
use futures::stream::{self, StreamExt, TryStreamExt};
//New hotness
/// Calculate the amount of dice to roll by consulting the database
/// and replacing variables with corresponding amounts. Errors out if
/// it cannot find a variable defined, or if the database errors.
pub async fn calculate_dice_amount(amounts: &[Amount], ctx: &Context<'_>) -> Result<i32, BotError> {
let stream = stream::iter(amounts);
let key = UserAndRoom(&ctx.username, ctx.room.id.as_str());
let variables = &ctx.db.variables.get_user_variables(&key)?;
use DiceRollingError::VariableNotFound;
let dice_amount: Result<i32, BotError> = stream
let dice_amount: i32 = stream
.then(|amount| async move {
match &amount.element {
NewElement::Number(num_dice) => Ok(*num_dice * amount.operator.mult()),
NewElement::Number(num_dice) => Ok(num_dice * amount.operator.mult()),
NewElement::Variable(variable) => variables
.get(variable)
.ok_or(VariableNotFound(variable.clone().to_string()))
.map(|i| *i)
.map_err(|e| e.into()),
.ok_or_else(|| VariableNotFound(variable.clone()))
.map(|i| *i),
}
})
.try_fold(0, |total, num_dice| async move { Ok(total + num_dice) })
.await;
.await?;
dice_amount
Ok(dice_amount)
}