Created a new Loader module and some stubs

src/lib.rs

@@ -89,6 +89,7 @@ mod parse;
 pub mod renderer;
 pub mod theme;
 pub mod utils;
+pub mod loader;
 
 pub use book::MDBook;
 pub use book::BookItem;

src/loader/mod.rs

@@ -0,0 +1,29 @@
+//! Functionality for loading the internal book representation from disk.
+
+#![deny(missing_docs)]
+
+use std::path::{Path, PathBuf};
+use std::error::Error;
+
+
+/// The object in charge of parsing the source directory into a usable
+/// `Book` struct.
+#[derive(Debug, Clone, PartialEq)]
+pub struct Loader {
+    source_directory: PathBuf,
+}
+
+impl Loader {
+    /// Create a new loader which uses the provided source directory.
+    pub fn new<P: AsRef<Path>>(source_directory: P) -> Loader {
+        Loader { source_directory: source_directory.as_ref().to_path_buf() }
+    }
+
+    /// Parse the `SUMMARY.md` file.
+    pub fn parse_summary(&self) -> Result<Summary, Box<Error>> {
+        unimplemented!()
+    }
+}
+
+/// The parsed `SUMMARY.md`, specifying how the book should be laid out.
+pub struct Summary;