src/main.rs

@@ -3,13 +3,41 @@
 //! This binary should just take any amount of numbers and print them out formatted to some other
 //! system.
 
+use std::io::Read;
+use std::process::exit;
+
 use clap::Parser;
 
 mod format;
 use format::*;
 
 fn main() {
-    let options = FormatOptions::parse();
+    // try to read from stdin first, appending the numbers we read to the FormatOptions
+    let mut args: Vec<String> = std::env::args_os()
+        .map(|x| x.into_string().unwrap())
+        .collect();
+    let mut stdin_nums = Vec::new();
+    match std::io::stdin().lock().read_to_end(&mut stdin_nums) {
+        Ok(_) => {
+            let whole: String = match String::from_utf8(stdin_nums) {
+                Ok(r) => r,
+                Err(e) => {
+                    eprintln!("stdin for this program only accepts text: {e:#?}");
+                    exit(1);
+                }
+            };
+            let split = whole.split_whitespace();
+            for s in split {
+                args.push(s.to_string());
+            }
+        }
+        Err(e) => {
+            eprintln!("could not read from stdin: {e:#?}");
+            exit(2);
+        }
+    };
+
+    let options = FormatOptions::parse_from(args);
 
     let mut out: Vec<String> = Vec::new();