Fix error implementation

Use `thiserror` to correctly implement error handling.
* Implementats the missing `impl Error`
* Adds `From` for error conversion

CHANGELOG.md

@@ -1,3 +1,7 @@
+<a name="v0.3.4"></a>
+### v0.3.4 (2022-11-15)
+* Add proper `Error` implementation to `Bounds` and `Center` parsing errors
+
 <a name="v0.3.3"></a>
 ### v0.3.3 (2022-11-07)
 * Add `Display` with precision support for `Bounds` and `Center` structs

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tilejson"
-version = "0.3.3"
+version = "0.3.4"
 description = "Library for serializing the TileJSON file format"
 authors = [
     "Stepan Kuzmin <[email protected]>",
@@ -19,3 +19,4 @@ categories = ["science::geo"]
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
 serde_tuple = "0.5"
+thiserror = "1"

src/bounds.rs

@@ -4,8 +4,9 @@ use std::ops::{Add, AddAssign};
 use std::str::FromStr;
 
 use serde_tuple::{Deserialize_tuple, Serialize_tuple};
+use thiserror::Error;
 
-use crate::ParseBoundsError::{BadLen, ParseCoordError};
+use crate::ParseBoundsError::BadLen;
 
 #[derive(Serialize_tuple, Deserialize_tuple, PartialEq, Debug, Copy, Clone)]
 pub struct Bounds {
@@ -163,21 +164,13 @@ impl AddAssign for Bounds {
     }
 }
 
-#[derive(Debug, PartialEq, Eq, Clone)]
+#[derive(Error, Debug, PartialEq, Eq, Clone)]
 pub enum ParseBoundsError {
-    /// Incorrect number of values
+    #[error("Incorrect number of values. Bounds expects four f64 values.")]
     BadLen,
     /// Wrapped error from the `parse::<f64>()`
-    ParseCoordError(ParseFloatError),
-}
-
-impl Display for ParseBoundsError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        match self {
-            BadLen => f.write_str("Incorrect number of values. Bounds expects four f64 values."),
-            ParseCoordError(e) => e.fmt(f),
-        }
-    }
+    #[error(transparent)]
+    ParseCoordError(#[from] ParseFloatError),
 }
 
 impl From<[f64; 4]> for Bounds {
@@ -333,8 +326,7 @@ impl FromStr for Bounds {
                 .next()
                 .ok_or(ParseBoundsError::BadLen)?
                 .trim()
-                .parse()
-                .map_err(ParseBoundsError::ParseCoordError)?;
+                .parse()?;
         }
         values
             .next()
@@ -345,7 +337,7 @@ impl FromStr for Bounds {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::ParseBoundsError::BadLen;
+    use crate::ParseBoundsError::{BadLen, ParseCoordError};
 
     #[test]
     fn test_parse_err() {

src/center.rs

@@ -3,6 +3,7 @@ use std::num::{ParseFloatError, ParseIntError};
 use std::str::FromStr;
 
 use serde_tuple::{Deserialize_tuple, Serialize_tuple};
+use thiserror::Error;
 
 #[derive(Serialize_tuple, Deserialize_tuple, PartialEq, Debug, Default, Copy, Clone)]
 pub struct Center {
@@ -42,26 +43,16 @@ impl Display for Center {
     }
 }
 
-#[derive(Debug, PartialEq, Eq, Clone)]
+#[derive(Error, Debug, PartialEq, Eq, Clone)]
 pub enum ParseCenterError {
-    /// Incorrect number of values
+    #[error("Incorrect number of values. Center expects two f64 and one u8 values.")]
     BadLen,
     /// Wrapped error from the `parse::<f64>()`
-    ParseCoordError(ParseFloatError),
+    #[error(transparent)]
+    ParseCoordError(#[from] ParseFloatError),
     /// Wrapped error from the `parse::<u8>()`
-    ParseZoomError(ParseIntError),
-}
-
-impl Display for ParseCenterError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        match self {
-            ParseCenterError::BadLen => {
-                f.write_str("Incorrect number of values. Center expects two f64 and one u8 values.")
-            }
-            ParseCenterError::ParseCoordError(e) => e.fmt(f),
-            ParseCenterError::ParseZoomError(e) => e.fmt(f),
-        }
-    }
+    #[error(transparent)]
+    ParseZoomError(#[from] ParseIntError),
 }
 
 impl FromStr for Center {
@@ -80,15 +71,9 @@ impl FromStr for Center {
         let mut vals = s.split(',').map(|s| s.trim());
         let mut next_val = || vals.next().ok_or(ParseCenterError::BadLen);
         let center = Self {
-            longitude: next_val()?
-                .parse()
-                .map_err(ParseCenterError::ParseCoordError)?,
-            latitude: next_val()?
-                .parse()
-                .map_err(ParseCenterError::ParseCoordError)?,
-            zoom: next_val()?
-                .parse()
-                .map_err(ParseCenterError::ParseZoomError)?,
+            longitude: next_val()?.parse()?,
+            latitude: next_val()?.parse()?,
+            zoom: next_val()?.parse()?,
         };
         match vals.next() {
             Some(_) => Err(ParseCenterError::BadLen),