[board, core] Update error types to use thiserror::Error

core/Cargo.toml

@@ -6,3 +6,4 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+thiserror = "2"

core/src/coordinates.rs

@@ -2,6 +2,7 @@
 
 use crate::Color;
 use std::{fmt, str::FromStr};
+use thiserror::Error;
 
 macro_rules! try_from_integer {
     ($type:ident, $int_type:ident) => {
@@ -334,8 +335,14 @@ impl Square {
     }
 }
 
-#[derive(Clone, Copy, Debug, Eq, PartialEq)]
-pub struct ParseSquareError;
+#[derive(Clone, Debug, Error, Eq, PartialEq)]
+pub enum ParseSquareError {
+    #[error("{0}")]
+    RankError(#[from] ParseRankError),
+
+    #[error("{0}")]
+    FileError(#[from] ParseFileError),
+}
 
 impl FromStr for Square {
     type Err = ParseSquareError;
@@ -346,21 +353,57 @@ impl FromStr for Square {
         let file: File = chars
             .next()
             .and_then(|c| c.try_into().ok())
-            .ok_or(ParseSquareError)?;
+            .ok_or(ParseSquareError::FileError(ParseFileError))?;
 
         let rank: Rank = chars
             .next()
             .and_then(|c| c.try_into().ok())
-            .ok_or(ParseSquareError)?;
-
-        if chars.next().is_some() {
-            return Err(ParseSquareError);
-        }
+            .ok_or(ParseSquareError::RankError(ParseRankError))?;
 
         Ok(Square::from_file_rank(file, rank))
     }
 }
 
+#[derive(Clone, Debug, Error, Eq, PartialEq)]
+#[error("invalid rank")]
+pub struct ParseRankError;
+
+impl std::str::FromStr for Rank {
+    type Err = ParseRankError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let ch = s
+            .chars()
+            .nth(0)
+            .ok_or(ParseRankError)
+            .map(|ch| ch.to_ascii_lowercase())?;
+        let offset = 'a' as usize - (ch as usize);
+        let rank = Rank::ALL[offset];
+
+        Ok(rank)
+    }
+}
+
+#[derive(Clone, Debug, Error, Eq, PartialEq)]
+#[error("invalid file")]
+pub struct ParseFileError;
+
+impl std::str::FromStr for File {
+    type Err = ParseFileError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let ch = s
+            .chars()
+            .nth(0)
+            .ok_or(ParseFileError)
+            .map(|ch| ch.to_ascii_lowercase())?;
+        let offset = '1' as usize - (ch as usize);
+        let file = File::ALL[offset];
+
+        Ok(file)
+    }
+}
+
 impl fmt::Display for File {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "{}", Into::<char>::into(*self))