feat: add sum method

01.workspace/oxydice_lib/src/imp/dice_roll.rs

@@ -1,10 +1,11 @@
 use crate::*;
 
 impl Dice {
-    pub fn roll(&mut self) {
+    pub fn roll(mut self) -> Self {
         self.roll_results.clear();
         for die in &self.handful {
             self.roll_results.push(die.roll())
         }
+        self
     }
 }

01.workspace/oxydice_lib/src/imp/dice_sum.rs

@@ -0,0 +1,16 @@
+use crate::*;
+
+impl Dice {
+    pub fn sum(self) -> Result<Sum, FailedTo> {
+        let mut result = Sum::default();
+        for roll_result in self.roll_results {
+            result.roll_results.push(roll_result);
+            result.sum = result
+                .sum
+                .checked_add(roll_result.into())
+                .and_then(|r| r.checked_add(1u64))
+                .ok_or(FailedTo::Sum)?;
+        }
+        Ok(result)
+    }
+}

01.workspace/oxydice_lib/src/imp/mod.rs

@@ -1,3 +1,4 @@
 pub mod dice_grab;
 pub mod dice_roll;
+pub mod dice_sum;
 pub mod die_roll;

01.workspace/oxydice_lib/src/lib.rs

@@ -11,7 +11,10 @@ mod tst;
 
 pub(crate) use crate::str::dice::O as Dice;
 pub(crate) use crate::str::die::O as Die;
+pub(crate) use crate::str::failed_to::E as FailedTo;
+pub(crate) use crate::str::sum::O as Sum;
 
 pub mod dice {
     pub use crate::str::dice::O as Dice;
+    pub use crate::str::sum::O as Sum;
 }

01.workspace/oxydice_lib/src/str/failed_to.rs

@@ -0,0 +1,51 @@
+// use crate::*;
+// use std::fmt::Display;
+// use std::str::FromStr;
+
+#[derive(Debug, PartialEq, PartialOrd, Eq, Ord, Clone, Copy, Hash)]
+pub enum E {
+    Sum,
+}
+
+// impl Display for E {
+// fn fmt(&self, f: &mut std::fmt::Formatter) -> std::result::Result<(), std::fmt::Error> {
+// match self {
+// Self::NoValue => write!(f, "NoValue"),
+// }
+// }
+// }
+
+// impl FromStr for E {
+// type Err = Box<dyn std::error::Error>;
+// fn from_str(value: &str) -> std::result::Result<Self, Box<dyn std::error::Error>> {
+// match value {
+// "NoValue" => Ok(Self::NoValue),
+// _ => unreachable!(),
+// }
+// }
+// }
+
+// #[cfg(test)]
+// mod unit_tests {
+// use super::*;
+// #[test]
+// fn check_001() {
+// for value in [E::NoValue] {
+// match value {
+// E::NoValue => assert_eq!(
+// E::NoValue,
+// E::from_str("NoValue").unwrap()
+// ),
+// }
+// }
+// }
+//
+// #[test]
+// fn check_002() {
+// for value in [E::NoValue] {
+// match value {
+// E::NoValue => assert_eq!(&E::NoValue.to_string(), "NoValue"),
+// }
+// }
+// }
+// }

01.workspace/oxydice_lib/src/str/mod.rs

@@ -1,2 +1,4 @@
 pub mod dice;
 pub mod die;
+pub mod failed_to;
+pub mod sum;

01.workspace/oxydice_lib/src/str/sum.rs

@@ -0,0 +1,18 @@
+use crate::*;
+
+#[derive(Debug, Default, PartialEq, Clone)]
+pub struct O {
+    pub(crate) roll_results: Vec<u16>,
+    pub(crate) sum: u64,
+}
+
+// impl std::fmt::Display for O {
+// fn fmt(&self, _f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+// todo!();
+// }
+// }
+
+// #[cfg(test)]
+// mod unit_tests {
+// use super::*;
+// }

01.workspace/oxydice_lib/src/tst/dice_roll.rs

@@ -3,15 +3,13 @@ mod tests {
     use crate::*;
     #[test]
     pub fn roll_should_yield_correct_number_or_results() {
-        let mut dice = Dice::grab(3, 6);
-        dice.roll();
+        let dice = Dice::grab(3, 6);
+        let dice = dice.roll();
         assert_eq!(dice.roll_results.len(), 3);
     }
     #[test]
     fn reroll_should_yield_correct_number_of_results() {
-        let mut dice = Dice::grab(3, 6);
-        dice.roll();
-        dice.roll();
+        let dice = Dice::grab(3, 6).roll().roll();
         assert_eq!(dice.roll_results.len(), 3);
     }
 }

01.workspace/oxydice_lib/src/tst/dice_sum.rs

@@ -0,0 +1,16 @@
+#[cfg(test)]
+mod tests {
+    use crate::*;
+    #[test]
+    pub fn dice_sum_should_yield_the_correct_sum() {
+        let result = Dice::grab(6, 1).roll().sum().unwrap();
+        assert_eq!(result.sum, 6);
+    }
+    #[test]
+    fn dice_sum_should_list_the_correct_results() {
+        let result = Dice::grab(6, 1).roll().sum().unwrap();
+        for idx in 1..6 {
+            assert_eq!(result.roll_results[idx], 0);
+        }
+    }
+}

01.workspace/oxydice_lib/src/tst/mod.rs

@@ -1,3 +1,4 @@
 pub mod dice_grab;
-pub mod die_roll;
 pub mod dice_roll;
+pub mod dice_sum;
+pub mod die_roll;