start adding error handling (WIP)

src/main.rs

@@ -4,10 +4,19 @@ mod reader;
 mod tacview;
 mod writer;
 
+use std::process;
+
 use crate::{tacview::Coalition, writer::StringWriter};
 
 fn main() {
-    let (input_filename, is_zip) = reader::find_input_file();
+    if let Err(err) = main_inner() {
+        eprintln!("{err}");
+        process::exit(1);
+    }
+}
+
+fn main_inner() -> Result<(), Box<dyn std::error::Error>> {
+    let (input_filename, is_zip) = reader::find_input_file()?;
     println!("Processing {}", input_filename);
     let lines = reader::read_data(&input_filename, is_zip);
     let (header, body) = processor::split_into_header_and_body(&lines);
@@ -25,4 +34,5 @@ fn main() {
     let mut purple_writer = writer::create_writer(is_zip, &input_filename);
     purple_writer.write_strings(header);
     purple_writer.write_for_coalition(body, &coalition_per_line, Coalition::Purple);
+    Ok(())
 }