Implement support for user variables in CoC dice rolling.

Also comes with reorganization of the dice rolling code to centralize
the variable -> dice amount logic, and changes the way the results of
those rolls are displayed.

src/cofd/dice.rs

@@ -1,22 +1,10 @@
 use crate::context::Context;
-use crate::db::variables::UserAndRoom;
+use crate::error::{BotError, DiceRollingError};
-use crate::error::BotError;
 use crate::parser::{Amount, Element, Operator};
 use crate::roll::Rolled;
-use futures::stream::{self, StreamExt, TryStreamExt};
 use itertools::Itertools;
 use std::convert::TryFrom;
 use std::fmt;
-use thiserror::Error;
-
-#[derive(Error, Debug)]
-pub enum DiceRollingError {
-    #[error("variable not found: {0}")]
-    VariableNotFound(String),
-
-    #[error("dice pool expression too large")]
-    ExpressionTooLarge,
-}
 
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub enum DicePoolQuality {
@@ -94,29 +82,6 @@ pub struct DicePool {
     pub(crate) modifiers: DicePoolModifiers,
 }
 
-async fn calculate_dice_amount(pool: &DicePoolWithContext<'_>) -> Result<i32, BotError> {
-    let stream = stream::iter(&pool.0.amounts);
-    let key = UserAndRoom(&pool.1.username, &pool.1.room_id);
-    let variables = &pool.1.db.variables.get_user_variables(&key)?;
-
-    use DiceRollingError::VariableNotFound;
-    let dice_amount: Result<i32, BotError> = stream
-        .then(|amount| async move {
-            match &amount.element {
-                Element::Number(num_dice) => Ok(*num_dice * amount.operator.mult()),
-                Element::Variable(variable) => variables
-                    .get(variable)
-                    .ok_or(VariableNotFound(variable.clone().to_string()))
-                    .map(|i| *i)
-                    .map_err(|e| e.into()),
-            }
-        })
-        .try_fold(0, |total, num_dice| async move { Ok(total + num_dice) })
-        .await;
-
-    dice_amount
-}
-
 impl DicePool {
     pub fn easy_pool(dice_amount: i32, quality: DicePoolQuality) -> DicePool {
         DicePool {
@@ -346,7 +311,7 @@ pub async fn roll_pool(pool: &DicePoolWithContext<'_>) -> Result<RolledDicePool,
         return Err(DiceRollingError::ExpressionTooLarge.into());
     }
 
-    let num_dice = calculate_dice_amount(&pool).await?;
+    let num_dice = crate::dice::calculate_dice_amount(&pool.0.amounts, &pool.1).await?;
     let mut roller = RngDieRoller(rand::thread_rng());
 
     if num_dice > 0 {
@@ -563,9 +528,13 @@ mod tests {
         }];
 
         let pool = DicePool::new(amounts, DicePoolModifiers::default());
-        let pool_with_ctx = DicePoolWithContext(&pool, &ctx);
 
-        assert_eq!(calculate_dice_amount(&pool_with_ctx).await.unwrap(), 10);
+        assert_eq!(
+            crate::dice::calculate_dice_amount(&pool.amounts, &ctx)
+                .await
+                .unwrap(),
+            10
+        );
     }
 
     //DicePool tests

src/commands/cthulhu.rs

@@ -1,6 +1,6 @@
 use super::{Command, Execution};
 use crate::context::Context;
-use crate::cthulhu::dice::{AdvancementRoll, DiceRoll};
+use crate::cthulhu::dice::{regular_roll, AdvancementRoll, DiceRoll, DiceRollWithContext};
 use async_trait::async_trait;
 
 pub struct CthRoll(pub DiceRoll);
@@ -11,14 +11,25 @@ impl Command for CthRoll {
         "roll percentile pool"
     }
 
-    async fn execute(&self, _ctx: &Context<'_>) -> Execution {
+    async fn execute(&self, ctx: &Context<'_>) -> Execution {
-        //TODO this will be converted to a result when supporting variables.
+        let roll_with_ctx = DiceRollWithContext(&self.0, ctx);
-        let roll = self.0.roll();
+        let roll = regular_roll(&roll_with_ctx).await;
-        let plain = format!("Roll: {}\nResult: {}", self.0, roll);
+
+        let (plain, html) = match roll {
+            Ok(executed_roll) => {
+                let plain = format!("Roll: {}\nResult: {}", executed_roll, executed_roll.roll);
                 let html = format!(
                     "<p><strong>Roll:</strong> {}</p><p><strong>Result</strong>: {}</p>",
-            self.0, roll
+                    executed_roll, executed_roll.roll
                 );
+                (plain, html)
+            }
+            Err(e) => {
+                let plain = format!("Error: {}", e);
+                let html = format!("<p><strong>Error:</strong> {}</p>", e);
+                (plain, html)
+            }
+        };
 
         Execution { plain, html }
     }

src/cthulhu/dice.rs

@@ -1,19 +1,17 @@
+use crate::context::Context;
+use crate::error::{BotError, DiceRollingError};
+use crate::parser::Amount;
+use std::convert::TryFrom;
 use std::fmt;
 
 /// A planned dice roll.
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
 pub struct DiceRoll {
-    pub target: u32,
+    pub amounts: Vec<Amount>,
     pub modifier: DiceRollModifier,
 }
 
-impl fmt::Display for DiceRoll {
+pub struct DiceRollWithContext<'a>(pub &'a DiceRoll, pub &'a Context<'a>);
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        let message = format!("target: {}, with {}", self.target, self.modifier);
-        write!(f, "{}", message)?;
-        Ok(())
-    }
-}
 
 /// Potential modifier on the die roll to be made.
 #[derive(Clone, Copy, Debug, PartialEq)]
@@ -91,6 +89,26 @@ impl fmt::Display for RollResult {
     }
 }
 
+pub struct ExecutedDiceRoll {
+    /// The number we must meet for the roll to be considered a
+    /// success.
+    pub target: u32,
+
+    /// Stored for informational purposes in display.
+    pub modifier: DiceRollModifier,
+
+    /// The actual roll result.
+    pub roll: RolledDice,
+}
+
+impl fmt::Display for ExecutedDiceRoll {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let message = format!("target: {}, with {}", self.target, self.modifier);
+        write!(f, "{}", message)?;
+        Ok(())
+    }
+}
+
 //TODO need to keep track of all rolled numbers for informational purposes!
 /// The outcome of a roll.
 pub struct RolledDice {
@@ -100,10 +118,6 @@ pub struct RolledDice {
     /// The number we must meet for the roll to be considered a
     /// success.
     target: u32,
-
-    /// Stored for informational purposes in display.
-    #[allow(dead_code)]
-    modifier: DiceRollModifier,
 }
 
 impl RolledDice {
@@ -235,9 +249,14 @@ fn roll_percentile_dice<R: DieRoller>(roller: &mut R, unit_roll: u32) -> u32 {
     }
 }
 
-fn roll_regular_dice<R: DieRoller>(roll: &DiceRoll, roller: &mut R) -> RolledDice {
+fn roll_regular_dice<R: DieRoller>(
+    modifier: &DiceRollModifier,
+    target: u32,
+    roller: &mut R,
+) -> RolledDice {
     use DiceRollModifier::*;
-    let num_rolls = match roll.modifier {
+
+    let num_rolls = match modifier {
         Normal => 1,
         OneBonus | OnePenalty => 2,
         TwoBonus | TwoPenalty => 3,
@@ -249,7 +268,7 @@ fn roll_regular_dice<R: DieRoller>(roll: &DiceRoll, roller: &mut R) -> RolledDic
         .map(|_| roll_percentile_dice(roller, unit_roll))
         .collect();
 
-    let num_rolled = match roll.modifier {
+    let num_rolled = match modifier {
         Normal => rolls.first(),
         OneBonus | TwoBonus => rolls.iter().min(),
         OnePenalty | TwoPenalty => rolls.iter().max(),
@@ -257,9 +276,8 @@ fn roll_regular_dice<R: DieRoller>(roll: &DiceRoll, roller: &mut R) -> RolledDic
     .unwrap();
 
     RolledDice {
-        modifier: roll.modifier,
         num_rolled: *num_rolled,
-        target: roll.target,
+        target: target,
     }
 }
 
@@ -287,7 +305,6 @@ fn roll_advancement_dice<R: DieRoller>(
     }
 }
 
-impl DiceRoll {
 /// Make a roll with a target number and potential modifier. In a
 /// normal roll, only one percentile die is rolled (1d100). With
 /// bonuses or penalties, more dice are rolled, and either the lowest
@@ -296,10 +313,21 @@ impl DiceRoll {
 /// rolled separately from the tens place, and then the unit number is
 /// added to each potential roll before picking the lowest/highest
 /// result.
-    pub fn roll(&self) -> RolledDice {
+pub async fn regular_roll(
+    roll_with_ctx: &DiceRollWithContext<'_>,
+) -> Result<ExecutedDiceRoll, BotError> {
+    let target =
+        crate::dice::calculate_dice_amount(&roll_with_ctx.0.amounts, roll_with_ctx.1).await?;
+
+    let target = u32::try_from(target).map_err(|_| DiceRollingError::InvalidAmount)?;
     let mut roller = RngDieRoller(rand::thread_rng());
-        roll_regular_dice(&self, &mut roller)
+    let rolled_dice = roll_regular_dice(&roll_with_ctx.0.modifier, target, &mut roller);
-    }
+
+    Ok(ExecutedDiceRoll {
+        target: target,
+        modifier: roll_with_ctx.0.modifier,
+        roll: rolled_dice,
+    })
 }
 
 impl AdvancementRoll {
@@ -312,6 +340,8 @@ impl AdvancementRoll {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::db::Database;
+    use crate::parser::{Amount, Element, Operator};
 
     /// Generate a series of numbers manually for testing. For this
     /// die system, the first roll in the Vec should be the unit roll,
@@ -339,195 +369,141 @@ mod tests {
         }
     }
 
-    #[test]
+    #[tokio::test]
-    fn regular_roll_succeeds_when_below_target() {
+    async fn regular_roll_converts_u32_safely() {
         let roll = DiceRoll {
-            target: 50,
+            amounts: vec![Amount {
+                operator: Operator::Plus,
+                element: Element::Number(-10),
+            }],
             modifier: DiceRollModifier::Normal,
         };
 
+        let db = Database::new_temp().unwrap();
+        let ctx = Context::new(&db, "roomid", "username", "message");
+        let roll_with_ctx = DiceRollWithContext(&roll, &ctx);
+        let result = regular_roll(&roll_with_ctx).await;
+        assert!(result.is_err());
+        assert!(matches!(
+            result,
+            Err(BotError::DiceRollingError(DiceRollingError::InvalidAmount))
+        ));
+    }
+
+    #[test]
+    fn regular_roll_succeeds_when_below_target() {
         //Roll 30, succeeding.
         let mut roller = SequentialDieRoller::new(vec![0, 3]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
         assert_eq!(RollResult::Success, rolled.result());
     }
 
     #[test]
     fn regular_roll_hard_success_when_rolling_half() {
-        let roll = DiceRoll {
-            target: 50,
-            modifier: DiceRollModifier::Normal,
-        };
-
         //Roll 25, succeeding.
         let mut roller = SequentialDieRoller::new(vec![5, 2]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
         assert_eq!(RollResult::HardSuccess, rolled.result());
     }
 
     #[test]
     fn regular_roll_extreme_success_when_rolling_one_fifth() {
-        let roll = DiceRoll {
-            target: 50,
-            modifier: DiceRollModifier::Normal,
-        };
-
         //Roll 10, succeeding extremely.
         let mut roller = SequentialDieRoller::new(vec![0, 1]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
         assert_eq!(RollResult::ExtremeSuccess, rolled.result());
     }
 
     #[test]
     fn regular_roll_extreme_success_target_above_100() {
-        let roll = DiceRoll {
-            target: 150,
-            modifier: DiceRollModifier::Normal,
-        };
-
         //Roll 30, succeeding extremely.
         let mut roller = SequentialDieRoller::new(vec![0, 3]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 150, &mut roller);
         assert_eq!(RollResult::ExtremeSuccess, rolled.result());
     }
 
     #[test]
     fn regular_roll_critical_success_on_one() {
-        let roll = DiceRoll {
-            target: 50,
-            modifier: DiceRollModifier::Normal,
-        };
-
         //Roll 1.
         let mut roller = SequentialDieRoller::new(vec![1, 0]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
         assert_eq!(RollResult::CriticalSuccess, rolled.result());
     }
 
     #[test]
     fn regular_roll_fail_when_above_target() {
-        let roll = DiceRoll {
-            target: 50,
-            modifier: DiceRollModifier::Normal,
-        };
-
         //Roll 60.
         let mut roller = SequentialDieRoller::new(vec![0, 6]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
         assert_eq!(RollResult::Failure, rolled.result());
     }
 
     #[test]
     fn regular_roll_is_fumble_when_skill_below_50_and_roll_at_least_96() {
-        let roll = DiceRoll {
-            target: 49,
-            modifier: DiceRollModifier::Normal,
-        };
-
         //Roll 96.
         let mut roller = SequentialDieRoller::new(vec![6, 9]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 49, &mut roller);
         assert_eq!(RollResult::Fumble, rolled.result());
     }
 
     #[test]
     fn regular_roll_is_failure_when_skill_at_or_above_50_and_roll_at_least_96() {
-        let roll = DiceRoll {
-            target: 50,
-            modifier: DiceRollModifier::Normal,
-        };
-
         //Roll 96.
         let mut roller = SequentialDieRoller::new(vec![6, 9]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
         assert_eq!(RollResult::Failure, rolled.result());
 
-        let roll = DiceRoll {
-            target: 68,
-            modifier: DiceRollModifier::Normal,
-        };
-
         //Roll 96.
         let mut roller = SequentialDieRoller::new(vec![6, 9]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 68, &mut roller);
         assert_eq!(RollResult::Failure, rolled.result());
     }
 
     #[test]
     fn regular_roll_always_fumble_on_100() {
-        let roll = DiceRoll {
-            target: 100,
-            modifier: DiceRollModifier::Normal,
-        };
-
         //Roll 100.
         let mut roller = SequentialDieRoller::new(vec![0, 0]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 100, &mut roller);
         assert_eq!(RollResult::Fumble, rolled.result());
     }
 
     #[test]
     fn one_penalty_picks_highest_of_two() {
-        let roll = DiceRoll {
-            target: 50,
-            modifier: DiceRollModifier::OnePenalty,
-        };
-
         //Should only roll 30 and 40, not 50.
         let mut roller = SequentialDieRoller::new(vec![0, 3, 4, 5]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::OnePenalty, 50, &mut roller);
         assert_eq!(40, rolled.num_rolled);
     }
 
     #[test]
     fn two_penalty_picks_highest_of_three() {
-        let roll = DiceRoll {
-            target: 50,
-            modifier: DiceRollModifier::TwoPenalty,
-        };
-
         //Should only roll 30, 40, 50, and not 60.
         let mut roller = SequentialDieRoller::new(vec![0, 3, 4, 5, 6]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::TwoPenalty, 50, &mut roller);
         assert_eq!(50, rolled.num_rolled);
     }
 
     #[test]
     fn one_bonus_picks_lowest_of_two() {
-        let roll = DiceRoll {
-            target: 50,
-            modifier: DiceRollModifier::OneBonus,
-        };
-
         //Should only roll 30 and 40, not 20.
         let mut roller = SequentialDieRoller::new(vec![0, 3, 4, 2]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::OneBonus, 50, &mut roller);
         assert_eq!(30, rolled.num_rolled);
     }
 
     #[test]
     fn two_bonus_picks_lowest_of_three() {
-        let roll = DiceRoll {
-            target: 50,
-            modifier: DiceRollModifier::TwoBonus,
-        };
-
         //Should only roll 30, 40, 50, and not 20.
         let mut roller = SequentialDieRoller::new(vec![0, 3, 4, 5, 2]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::TwoBonus, 50, &mut roller);
         assert_eq!(30, rolled.num_rolled);
     }
 
     #[test]
     fn normal_modifier_rolls_once() {
-        let roll = DiceRoll {
-            target: 50,
-            modifier: DiceRollModifier::Normal,
-        };
-
         //Should only roll 30, not 40.
         let mut roller = SequentialDieRoller::new(vec![0, 3, 4]);
-        let rolled = roll_regular_dice(&roll, &mut roller);
+        let rolled = roll_regular_dice(&DiceRollModifier::Normal, 50, &mut roller);
         assert_eq!(30, rolled.num_rolled);
     }
 

src/cthulhu/parser.rs

@@ -3,33 +3,40 @@ use crate::parser::DiceParsingError;
 
 //TOOD convert these to use parse_amounts from the common dice code.
 
-fn parse_modifier(input: &str) -> Result<(DiceRollModifier, &str), DiceParsingError> {
+fn parse_modifier(input: &str) -> Result<DiceRollModifier, DiceParsingError> {
     if input.ends_with("bb") {
-        Ok((DiceRollModifier::TwoBonus, input.trim_end_matches("bb")))
+        Ok(DiceRollModifier::TwoBonus)
     } else if input.ends_with("b") {
-        Ok((DiceRollModifier::OneBonus, input.trim_end_matches("b")))
+        Ok(DiceRollModifier::OneBonus)
     } else if input.ends_with("pp") {
-        Ok((DiceRollModifier::TwoPenalty, input.trim_end_matches("pp")))
+        Ok(DiceRollModifier::TwoPenalty)
     } else if input.ends_with("p") {
-        Ok((DiceRollModifier::OnePenalty, input.trim_end_matches("p")))
+        Ok(DiceRollModifier::OnePenalty)
     } else {
-        Ok((DiceRollModifier::Normal, input))
+        Ok(DiceRollModifier::Normal)
     }
 }
 
+//Make diceroll take a vec of Amounts
+//Split based on :, send first part to parse_modifier.
+//Send second part to parse_amounts
+
 pub fn parse_regular_roll(input: &str) -> Result<DiceRoll, DiceParsingError> {
-    let input = input.trim();
+    let input: Vec<&str> = input.trim().split(":").collect();
-    let (modifier, input) = parse_modifier(input)?;
+
-    let target: u32 = input.parse().map_err(|_| DiceParsingError::InvalidAmount)?;
+    let (modifiers_str, amounts_str) = match input[..] {
+        [amounts] => Ok(("", amounts)),
+        [modifiers, amounts] => Ok((modifiers, amounts)),
+        _ => Err(DiceParsingError::UnconsumedInput),
+    }?;
+
+    let modifier = parse_modifier(modifiers_str)?;
+    let amounts = crate::parser::parse_amounts(amounts_str)?;
 
-    if target <= 100 {
     Ok(DiceRoll {
-            target: target,
+        amounts: amounts,
         modifier: modifier,
     })
-    } else {
-        Err(DiceParsingError::InvalidAmount)
-    }
 }
 
 pub fn parse_advancement_roll(input: &str) -> Result<AdvancementRoll, DiceParsingError> {
@@ -49,6 +56,7 @@ pub fn parse_advancement_roll(input: &str) -> Result<AdvancementRoll, DiceParsin
 mod tests {
 
     use super::*;
+    use crate::parser::{Amount, Element, Operator};
 
     #[test]
     fn regular_roll_accepts_single_number() {
@@ -56,7 +64,10 @@ mod tests {
         assert!(result.is_ok());
         assert_eq!(
             DiceRoll {
-                target: 60,
+                amounts: vec![Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(60)
+                }],
                 modifier: DiceRollModifier::Normal
             },
             result.unwrap()
@@ -65,11 +76,14 @@ mod tests {
 
     #[test]
     fn regular_roll_accepts_two_bonus() {
-        let result = parse_regular_roll("60bb");
+        let result = parse_regular_roll("bb:60");
         assert!(result.is_ok());
         assert_eq!(
             DiceRoll {
-                target: 60,
+                amounts: vec![Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(60)
+                }],
                 modifier: DiceRollModifier::TwoBonus
             },
             result.unwrap()
@@ -78,11 +92,14 @@ mod tests {
 
     #[test]
     fn regular_roll_accepts_one_bonus() {
-        let result = parse_regular_roll("60b");
+        let result = parse_regular_roll("b:60");
         assert!(result.is_ok());
         assert_eq!(
             DiceRoll {
-                target: 60,
+                amounts: vec![Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(60)
+                }],
                 modifier: DiceRollModifier::OneBonus
             },
             result.unwrap()
@@ -91,11 +108,14 @@ mod tests {
 
     #[test]
     fn regular_roll_accepts_two_penalty() {
-        let result = parse_regular_roll("60pp");
+        let result = parse_regular_roll("pp:60");
         assert!(result.is_ok());
         assert_eq!(
             DiceRoll {
-                target: 60,
+                amounts: vec![Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(60)
+                }],
                 modifier: DiceRollModifier::TwoPenalty
             },
             result.unwrap()
@@ -104,11 +124,14 @@ mod tests {
 
     #[test]
     fn regular_roll_accepts_one_penalty() {
-        let result = parse_regular_roll("60p");
+        let result = parse_regular_roll("p:60");
         assert!(result.is_ok());
         assert_eq!(
             DiceRoll {
-                target: 60,
+                amounts: vec![Amount {
+                    operator: Operator::Plus,
+                    element: Element::Number(60)
+                }],
                 modifier: DiceRollModifier::OnePenalty
             },
             result.unwrap()
@@ -121,21 +144,21 @@ mod tests {
         assert!(parse_regular_roll("   60").is_ok());
         assert!(parse_regular_roll("   60    ").is_ok());
 
-        assert!(parse_regular_roll("60bb     ").is_ok());
+        assert!(parse_regular_roll("bb:60     ").is_ok());
-        assert!(parse_regular_roll("   60bb").is_ok());
+        assert!(parse_regular_roll("   bb:60").is_ok());
-        assert!(parse_regular_roll("   60bb    ").is_ok());
+        assert!(parse_regular_roll("   bb:60    ").is_ok());
 
-        assert!(parse_regular_roll("60b     ").is_ok());
+        assert!(parse_regular_roll("b:60     ").is_ok());
-        assert!(parse_regular_roll("   60b").is_ok());
+        assert!(parse_regular_roll("   b:60").is_ok());
-        assert!(parse_regular_roll("   60b    ").is_ok());
+        assert!(parse_regular_roll("   b:60    ").is_ok());
 
-        assert!(parse_regular_roll("60pp     ").is_ok());
+        assert!(parse_regular_roll("pp:60     ").is_ok());
-        assert!(parse_regular_roll("   60pp").is_ok());
+        assert!(parse_regular_roll("   pp:60").is_ok());
-        assert!(parse_regular_roll("   60pp    ").is_ok());
+        assert!(parse_regular_roll("   pp:60    ").is_ok());
 
-        assert!(parse_regular_roll("60p     ").is_ok());
+        assert!(parse_regular_roll("p:60     ").is_ok());
-        assert!(parse_regular_roll("   60p").is_ok());
+        assert!(parse_regular_roll("   p:60").is_ok());
-        assert!(parse_regular_roll("   60p    ").is_ok());
+        assert!(parse_regular_roll("   p:60    ").is_ok());
     }
 
     #[test]
@@ -152,21 +175,11 @@ mod tests {
         assert_eq!(AdvancementRoll { existing_skill: 60 }, result.unwrap());
     }
 
-    #[test]
-    fn regular_roll_rejects_big_numbers() {
-        assert!(parse_regular_roll("3000").is_err());
-    }
-
     #[test]
     fn advancement_roll_rejects_big_numbers() {
         assert!(parse_advancement_roll("3000").is_err());
     }
 
-    #[test]
-    fn regular_roll_rejects_invalid_input() {
-        assert!(parse_regular_roll("abc").is_err());
-    }
-
     #[test]
     fn advancement_roll_rejects_invalid_input() {
         assert!(parse_advancement_roll("abc").is_err());

src/dice.rs

@@ -1,8 +1,41 @@
 pub mod parser;
 
+use crate::context::Context;
+use crate::db::variables::UserAndRoom;
+use crate::error::BotError;
+use crate::error::DiceRollingError;
+use crate::parser::Amount;
+use crate::parser::Element as NewElement;
+use futures::stream::{self, StreamExt, TryStreamExt};
 use std::fmt;
 use std::ops::{Deref, DerefMut};
 
+//New hotness
+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);
+    let variables = &ctx.db.variables.get_user_variables(&key)?;
+
+    use DiceRollingError::VariableNotFound;
+    let dice_amount: Result<i32, BotError> = stream
+        .then(|amount| async move {
+            match &amount.element {
+                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()),
+            }
+        })
+        .try_fold(0, |total, num_dice| async move { Ok(total + num_dice) })
+        .await;
+
+    dice_amount
+}
+
+//Old stuff, for regular dice rolling. To be moved elsewhere.
+
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
 pub struct Dice {
     pub(crate) count: u32,

src/error.rs

@@ -1,4 +1,3 @@
-use crate::cofd::dice::DiceRollingError;
 use crate::commands::CommandError;
 use crate::config::ConfigError;
 use crate::db::errors::DataError;
@@ -50,7 +49,7 @@ pub enum BotError {
     #[error("command parsing error: {0}")]
     CommandParsingError(#[from] crate::commands::parser::CommandParsingError),
 
-    #[error("dice pool roll error: {0}")]
+    #[error("dice rolling error: {0}")]
     DiceRollingError(#[from] DiceRollingError),
 
     #[error("variable parsing error: {0}")]
@@ -68,3 +67,15 @@ pub enum BotError {
     #[error("database error")]
     DatabaseErrror(#[from] sled::Error),
 }
+
+#[derive(Error, Debug)]
+pub enum DiceRollingError {
+    #[error("variable not found: {0}")]
+    VariableNotFound(String),
+
+    #[error("invalid amount")]
+    InvalidAmount,
+
+    #[error("dice pool expression too large")]
+    ExpressionTooLarge,
+}