prepare for batch processing.

src/main.rs

@@ -7,6 +7,10 @@ mod prolog;
 use prolog::io::*;
 use prolog::machine::*;
 
+use std::fs::File;
+use std::io::prelude::*;
+use std::path::Path;
+
 #[cfg(test)]
 mod tests;
 
@@ -24,6 +28,8 @@ fn process_buffer(wam: &mut Machine, buffer: &str)
 fn prolog_repl() {
     let mut wam = Machine::new();
 
+    load_init_file(&mut wam, "lists.pl");
+               
     loop {
         print!("prolog> ");