Split error enum into Encode vs. Decode errors

src/error.rs

@@ -2,7 +2,7 @@ use nom::error::{ErrorKind, ParseError as NomParseError};
 use thiserror::Error;
 
 #[derive(Debug, Error)]
-pub enum ParseError {
+pub enum DecodeError {
     #[error("invalid ZZT file magic")]
     InvalidMagic,
 
@@ -12,20 +12,11 @@ pub enum ParseError {
     #[error("negative stat count")]
     NegativeStatCount,
 
-    #[error("string too long")]
-    StringTooLong { max: u8 },
-
-    #[error("cannot encode character: {0}")]
-    EncodingError(char),
-
-    #[error("board data too large")]
-    BoardTooLarge,
-
     #[error("nom error: {0}")]
     NomError(String),
 }
 
-impl<I> NomParseError<I> for ParseError {
+impl<I> NomParseError<I> for DecodeError {
     fn from_error_kind(_input: I, kind: ErrorKind) -> Self {
         Self::NomError(kind.description().to_string())
     }
@@ -35,11 +26,26 @@ impl<I> NomParseError<I> for ParseError {
     }
 }
 
-impl From<nom::Err<ParseError>> for ParseError {
-    fn from(value: nom::Err<ParseError>) -> Self {
+impl From<nom::Err<DecodeError>> for DecodeError {
+    fn from(value: nom::Err<DecodeError>) -> Self {
         match value {
             nom::Err::Error(e) | nom::Err::Failure(e) => e,
             nom::Err::Incomplete(needed) => Self::NomError(format!("incomplete: {:?}", needed)),
         }
     }
 }
+
+#[derive(Debug, Error)]
+pub enum EncodeError {
+    #[error("invalid tile count: {0}")]
+    InvalidTileCount(usize),
+
+    #[error("string too long")]
+    StringTooLong { max: u8 },
+
+    #[error("cannot encode character: {0}")]
+    EncodingError(char),
+
+    #[error("board data too large")]
+    BoardTooLarge,
+}