isabelle2unicode: read from files, cli argumentsHEADmaster

1 files changed, 42 insertions, 4 deletions

diff --git a/isabelle2unicode/src/main.rs b/isabelle2unicode/src/main.rs
index 4670b38..7dcbf69 100644
--- a/isabelle2unicode/src/main.rs
+++ b/isabelle2unicode/src/main.rs
@@ -1,14 +1,52 @@
-use std::io;
-use std::io::BufRead;
+use std::ffi::OsString;
+use std::io::{self, BufReader, BufRead};
 
 use isabelle_unicode::PrettyUnicode;
 
 
+const HELP: &str =
+"isabelle2unicode: convert isabelle markup to unicode text.
+
+USAGE: isabelle2unicode [input file]
+
+Read in [input file] and convert any markup found to its equivalent symbols
+listed in Isabelle's etc/symbols file.
+
+If not given, read from stdin.
+
+OPTIONS:
+  -h --help: display this help
+";
+
+
 fn main() {
 
-    let stdin = io::stdin();
+    let args: Vec<OsString> = std::env::args_os().collect();
+
+    let ifile = match &args[1..] {
+        [] => None,
+        [h] if h.to_str() == Some("-h") || h.to_str() == Some("--help") => {
+            eprintln!("{}", HELP);
+            std::process::exit(0)
+        }
+        [ifile] => Some(ifile),
+        _ => {
+            eprintln!("{}", HELP);
+            std::process::exit(1)
+        }
+    };
+
+    let instream: Box<dyn BufRead> = match ifile {
+        None => Box::new(BufReader::new(io::stdin())),
+        Some(ref path) => {
+            let file = std::fs::File::open(path)
+                .expect(&format!("could not open file {}", path.to_string_lossy()));
+            Box::new(BufReader::new(file))
+        }
+    };
+
 
-    stdin.lock()
+    instream
          .lines()
          .filter_map(|line| match line {
              Ok(line) if line.trim().is_empty()