feat: add an empty error enum

01.workspace/oxidice_lib/src/lib.rs

@@ -6,3 +6,5 @@ mod mcr;
 mod str;
 mod trt;
 mod tst;
+
+pub(crate) use crate::str::failed_to::E as FailedTo;

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

@@ -0,0 +1,50 @@
+use crate::*;
+// use std::fmt::Display;
+// use std::str::FromStr;
+
+#[derive(Debug, PartialEq, PartialOrd, Eq, Ord, Clone, Copy, Hash)]
+pub enum E {
+}
+
+// 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/oxidice_lib/src/str/mod.rs

@@ -0,0 +1 @@
+pub mod failed_to;