Add friendlier output where possible

src/conlang.rs

@@ -0,0 +1,7 @@
+#[cfg(feature = "conlang")]
+const CONLANG_SUPPLEMENTAL: &str = include_str!("conlang-supplemental.pest");
+
+pub fn print_supplemental() {
+    #[cfg(feature = "conlang")]
+    println!("\n// CONLANG_SUPPLEMENTAL\n{CONLANG_SUPPLEMENTAL}");
+}

src/datetime.rs

@@ -0,0 +1,16 @@
+#[cfg(feature = "datetime")]
+use datetime::{LocalDateTime, ISO};
+
+#[cfg(feature = "datetime")]
+struct Now(LocalDateTime);
+#[cfg(feature = "datetime")]
+impl std::fmt::Display for Now {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+pub fn print_current_time() {
+    #[cfg(feature = "datetime")]
+    println!("// Generated {}", Now(LocalDateTime::now()))
+}

src/main.rs

@@ -1,19 +1,25 @@
+use grammatical::*;
 use std::error::Error;
 
-use grammatical::*;
+mod conlang;
+mod datetime;
 
 fn main() -> Result<(), Box<dyn Error>> {
-    for file in std::env::args().skip(1) {
+    datetime::print_current_time();
+    let args: Vec<_> = std::env::args().skip(1).collect();
+    if args.is_empty() {
+        for line in std::io::stdin().lines() {
+            let line = line?;
+            let mut p = Parser::new(&line);
+            parse(&mut p);
+        }
+    }
+    for file in args {
         let file = std::fs::read_to_string(file)?;
         let mut p = Parser::new(&file);
         parse(&mut p);
     }
-
-    for line in std::io::stdin().lines() {
-        let line = line?;
-        let mut p = Parser::new(&line);
-        parse(&mut p);
-    }
+    conlang::print_supplemental();
     Ok(())
 }