better argument parsing

src/main.rs

@@ -19,13 +19,14 @@
 
 use std::{
     env::args,
+    fs::File,
     io::{
         Read,
-        stdin,
         stdout,
         Stdout,
         Write,
     },
+    os::fd::FromRawFd,
 };
 
 use crossterm::{
@@ -353,24 +354,34 @@ fn screen_main(stdout: &mut Stdout, mut state: State) -> Result<()> {
 
 fn main() -> Result<()> {
     let argv = args().collect::<Vec<String>>();
+    let mut buf = Vec::new();
     let text: String;
 
-    if !argv.get(1).is_some() {
+    text = match argv.get(1) {
-        text = "".to_string();
+        Some(path) => {
-    } else {
+            match path.as_str() {
-        let mut buf = Vec::new();
+                "-" => unsafe { File::from_raw_fd(0) },
-        std::fs::File::open(argv[1].clone()).unwrap_or_else(|_| {
+                _ => {
-            eprintln!("{}: {}: No such file.", argv[0], argv[1]);
+                    std::fs::File::open(path).unwrap_or_else(|_| {
-            exit(EX_UNAVAILABLE);
+                        eprintln!(
-        }).read_to_end(&mut buf).unwrap();
+                            "{}: {}: No such file or directory.",
+                            argv[0],
+                            argv[1]
+                        );
+                        exit(EX_UNAVAILABLE);
+                    })
+                },
+            }.read_to_end(&mut buf).unwrap();
 
-        text = String::from_utf8(buf).unwrap_or_else(|_| {
+            String::from_utf8(buf).unwrap_or_else(|_| {
-            eprintln!(
+                eprintln!(
-                "{}: {}: File contents are invalid UTF-8.", argv[0], argv[1]
+                    "{}: {}: File contents are invalid UTF-8.", argv[0], argv[1]
-            );
+                );
-            exit(EX_DATAERR);
+                exit(EX_DATAERR);
-        });
+            })
-    }
+        },
+        None => "".to_string(),
+    };
 
     let state = State::from_str(&text)?;
     let mut stdout = stdout();