Switch the compiled bin to running a diff just like the automated tests.

This is mostly so I can test a variety of org-mode documents without needing to integrate them into the org samples folder.

src/main.rs

@@ -1,17 +1,51 @@
 #![feature(round_char_boundary)]
+use std::path::Path;
+
 use ::organic::parser::document;
+use organic::compare_document;
+use organic::emacs_parse_org_document;
+use organic::parser::sexp::sexp_with_padding;
 
 use crate::init_tracing::init_telemetry;
 use crate::init_tracing::shutdown_telemetry;
 mod init_tracing;
 
-const TEST_DOC: &'static str = include_str!("../toy_language.txt");
-
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     init_telemetry()?;
-    let parsed = document(TEST_DOC);
-    println!("{}\n\n\n", TEST_DOC);
-    println!("{:#?}", parsed);
+    run_compare(
+        std::env::args()
+            .nth(1)
+            .expect("Pass a single file into this script."),
+    )?;
     shutdown_telemetry()?;
     Ok(())
 }
+
+fn run_compare<P: AsRef<Path>>(todo_org_path: P) -> Result<(), Box<dyn std::error::Error>> {
+    let org_contents = std::fs::read_to_string(todo_org_path.as_ref()).expect("Read org file.");
+    let (remaining, rust_parsed) = document(org_contents.as_str()).expect("Org Parse failure");
+    let org_sexp =
+        emacs_parse_org_document(todo_org_path.as_ref()).expect("Use emacs to parse org file.");
+    let (_remaining, parsed_sexp) =
+        sexp_with_padding(org_sexp.as_str()).expect("Sexp Parse failure");
+
+    println!("{}\n\n\n", org_contents.as_str());
+    println!("{}", org_sexp);
+    println!("{:#?}", rust_parsed);
+
+    // We do the diffing after printing out both parsed forms in case the diffing panics
+    let diff_result =
+        compare_document(&parsed_sexp, &rust_parsed).expect("Compare parsed documents.");
+    diff_result
+        .print()
+        .expect("Print document parse tree diff.");
+
+    if diff_result.is_bad() {
+        Err("Diff results do not match.")?;
+    }
+    if remaining != "" {
+        Err(format!("There was unparsed text remaining: {}", remaining))?;
+    }
+
+    Ok(())
+}