Add discovery subcommands list and fields

crates/pile-dataset/src/extract/epub/mod.rs

@@ -1,5 +1,5 @@
 use pile_config::Label;
-use std::{collections::HashMap, sync::Arc};
+use std::sync::Arc;
 
 mod epub_meta;
 pub use epub_meta::*;
@@ -7,39 +7,30 @@ pub use epub_meta::*;
 mod epub_text;
 pub use epub_text::*;
 
-use crate::{
-	Item, PileValue,
-	extract::{MapExtractor, ObjectExtractor},
-};
+use crate::{Item, PileValue, extract::ObjectExtractor};
 
 pub struct EpubExtractor {
-	inner: MapExtractor,
+	text: Arc<EpubTextExtractor>,
+	meta: Arc<EpubMetaExtractor>,
 }
 
 impl EpubExtractor {
-	#[expect(clippy::unwrap_used)]
 	pub fn new(item: &Item) -> Self {
-		let inner = MapExtractor {
-			inner: HashMap::from([
-				(
-					Label::new("text").unwrap(),
-					PileValue::ObjectExtractor(Arc::new(EpubTextExtractor::new(item))),
-				),
-				(
-					Label::new("meta").unwrap(),
-					PileValue::ObjectExtractor(Arc::new(EpubMetaExtractor::new(item))),
-				),
-			]),
-		};
-
-		Self { inner }
+		Self {
+			text: Arc::new(EpubTextExtractor::new(item)),
+			meta: Arc::new(EpubMetaExtractor::new(item)),
+		}
 	}
 }
 
 #[async_trait::async_trait]
 impl ObjectExtractor for EpubExtractor {
 	async fn field(&self, name: &pile_config::Label) -> Result<Option<PileValue>, std::io::Error> {
-		self.inner.field(name).await
+		match name.as_str() {
+			"text" => self.text.field(name).await,
+			"meta" => Ok(Some(PileValue::ObjectExtractor(self.meta.clone()))),
+			_ => Ok(None),
+		}
 	}
 
 	#[expect(clippy::unwrap_used)]