Don't read templates in a loop

src/main.rs

     }
 }
 
-fn render_post(cwd: &path::PathBuf, layout: &str, post: &Post) {
-    let post_template = fs::read_to_string(cwd.join("templates").join("post.html"))
-        .expect("Couldn't find post template");
+fn render_post(cwd: &path::PathBuf, layout: &str, post_template: &str, post: &Post) {
     let output = layout.replace(
         "{{ contents }}",
         &post_template
     ).expect("Unable to write file");
 }
 
-fn render_post_listing(cwd: &path::PathBuf, layout: &str, posts: &Vec<Post>) {
-    let post_item_template =
-        fs::read_to_string(cwd.join("templates").join("post_listing_item.html"))
-            .expect("Couldn't find post listing item template");
+fn render_post_listing(cwd: &path::PathBuf, layout: &str, post_item_template: &str, posts: &Vec<Post>) {
     let post_listing = posts
         .iter()
         .map(|ref post| {
         },
     }
 
-    let layout = fs::read_to_string(&cwd.join("templates").join("layout.html"))
+    let layout_template = fs::read_to_string(&cwd.join("templates").join("layout.html"))
         .expect("Couldn't find layout template");
+    let post_template = fs::read_to_string(cwd.join("templates").join("post.html"))
+        .expect("Couldn't find post template");
+    let post_item_template =
+        fs::read_to_string(cwd.join("templates").join("post_listing_item.html"))
+            .expect("Couldn't find post listing item template");
+
     let post_paths = read_posts_dir(&cwd.join("posts"));
     let mut posts: Vec<Post> = vec![];
     for path in post_paths {
         match path {
             Ok(p) => {
                 let post = parse_post(p.path());
-                render_post(&cwd, &layout, &post);
+                render_post(&cwd, &layout_template, &post_template, &post);
                 posts.push(post);
             }
             Err(err) => panic!(err),
         }
     }
 
-    render_post_listing(&cwd, &layout, &posts);
+    render_post_listing(&cwd, &layout_template, &post_item_template, &posts);
 }