Add Level type

pica-record/src/level.rs

@@ -0,0 +1,46 @@
+use std::str::FromStr;
+
+use thiserror::Error;
+
+#[derive(Debug, Default, Clone, PartialEq, Eq)]
+pub enum Level {
+    #[default]
+    Main,
+    Local,
+    Copy,
+}
+
+/// An error that can occur when parsing PICA+ level.
+#[derive(Error, PartialEq, Eq, Debug)]
+#[error("{0}")]
+pub struct ParseLevelError(String);
+
+impl FromStr for Level {
+    type Err = ParseLevelError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s {
+            "main" => Ok(Self::Main),
+            "local" => Ok(Self::Local),
+            "copy" => Ok(Self::Copy),
+            _ => Err(ParseLevelError(format!("invalid level '{}'", s))),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+
+    use super::*;
+
+    #[test]
+    fn test_from_str() -> anyhow::Result<()> {
+        assert_eq!("main".parse::<Level>().unwrap(), Level::Main);
+        assert_eq!("local".parse::<Level>().unwrap(), Level::Local);
+        assert_eq!("copy".parse::<Level>().unwrap(), Level::Copy);
+        assert!("master".parse::<Level>().is_err());
+        assert!("foo".parse::<Level>().is_err());
+
+        Ok(())
+    }
+}

pica-record/src/lib.rs

@@ -5,13 +5,15 @@
 mod error;
 mod field;
 pub mod io;
+mod level;
 mod occurrence;
 mod record;
 mod subfield;
 mod tag;
 
 pub use error::ParsePicaError;
 pub use field::{Field, FieldMut, FieldRef};
+pub use level::Level;
 pub use occurrence::{Occurrence, OccurrenceMut, OccurrenceRef};
 pub use record::{
     ByteRecord, Record, RecordMut, RecordRef, StringRecord,