logging: make it configurable via new -v argument

Author: pazz

src/main.rs

@@ -39,6 +39,14 @@ struct Args {
     )]
     input_format: nfa::InputFormat,
 
+    #[arg(
+        short = 'v',
+        long = "verbose",
+        action = clap::ArgAction::Count,
+        help = "Increase verbosity level (use multiple times for more verbose output)"
+    )]
+    verbosity: u8,
+
     #[arg(
         value_enum,
         short = 't',
@@ -76,19 +84,21 @@ struct Args {
 }
 
 fn main() {
-    #[cfg(debug_assertions)]
-    env_logger::Builder::new()
-        .filter_level(LevelFilter::Debug)
-        .init();
-
-    #[cfg(not(debug_assertions))]
-    env_logger::Builder::new()
-        .filter_level(LevelFilter::Info)
-        .init();
 
     // parse CLI arguments
     let args = Args::parse();
 
+    // set up logging
+    let mut builder = env_logger::Builder::new();
+
+    match &args.verbosity {
+        0 => builder.filter_level(LevelFilter::Warn),
+        1 => builder.filter_level(LevelFilter::Info),
+        2 => builder.filter_level(LevelFilter::Debug),
+        _ => builder.filter_level(LevelFilter::Trace),
+    };
+    builder.init();
+
     // parse the input file
     let nfa = nfa::Nfa::load_from_file(&args.filename, &args.input_format, &args.state_ordering);