better sheet error display

poc/poc.yml

@@ -17,17 +17,17 @@ channels:
       notes: cCdDefFgGaAb
       sheet:
         aabc.
-        'rt°y
+        'ab°A
         +d+d+d---
         /ff/f\\
         ab>c<ba
         ;this is a comment (or lyrics whatever),
-        s:df
+        C:CC
         (3deff)
         (deff)
         [ffe]
         {l 1-cos((PI*x)/2),acced}
-        abbc!o5cc!v15feed!l4fedd!t60hdd
+        abbc!o5cc!v15feed!l4fedd!t60Gdd
         # rest: .
         # pizz.: '°
         # volume: +-

src/bng/score.rs

@@ -45,18 +45,18 @@ enum AtomsSerializeError {
 
 fn nom_err_message(e: nom::Err<nom::error::Error<&str>>) -> String {
     match e {
-        nom::Err::Incomplete(needed) => todo!(),
-        nom::Err::Error(e) => format!(
-            "got error code {code:#?} at character n°{charn} (after \"{before}\")",
-            code = e.code,
-            charn = e.input.len() + 1,
-            before = &e.input[e.input.len()
-                - option_env!("SHEET_BACKTRACE")
-                    .and_then(|s| s.parse().ok())
-                    .unwrap_or(10usize)
-                + 1..]
+        nom::Err::Incomplete(needed) => format!(
+            "input is incomplete, needed {} byte(s) more",
+            match needed {
+                nom::Needed::Unknown => "?".to_string(),
+                nom::Needed::Size(s) => s.to_string(),
+            }
+        ),
+        nom::Err::Error(e) | nom::Err::Failure(e) => format!(
+            "got error code {code:#?} at \"{input}\"",
+            code = e.code,
+            input = e.input
         ),
-        nom::Err::Failure(e) => todo!(),
     }
 }
 
@@ -127,7 +127,7 @@ impl<'de> Deserialize<'de> for Atoms {
         let x = all_consuming(terminated(
             many0(preceded(many0(one_of(" \t\r")), flat_atom_parser(&notes))),
             many0(alt((char('\t'), char(' '), char('\n'), char('\r')))),
-        ))(dbg!(&sheet))
+        ))(&sheet)
         .map_err(nom_err_message)
         .map_err(AtomsSerializeError::Parsing)
         .map_err(de::Error::custom)