conditional cli args

Cargo.toml

@@ -5,11 +5,15 @@ edition = "2021"
 
 [dependencies]
 anyhow = "1.0"
+cfg-if = "1.0.0"
 clap = { version = "4.5", features = ["derive"] }
 fasteval = "0.2.4"
 tinyaudio = { version = "0.1", optional = true }
 
 [features]
+# default = []
+# default = ["save"]
+# default = ["play"]
 default = ["play", "save"]
 play = ["dep:tinyaudio"]
 save = []

src/cli.rs

@@ -1,21 +1,54 @@
 use std::{fs::read_to_string, ops::Deref, path::Path, str::FromStr};
+cfg_if! {
+    if #[cfg(save)] {
+        use std::path::PathBuf;
+    }
+}
 
 use anyhow::{Context, Error};
+use cfg_if::cfg_if;
 use clap::Parser;
 
 #[derive(Parser)]
+#[cfg_attr(debug_assertions, derive(Debug))]
 pub(super) struct Args {
     #[arg(short, long, value_parser = Instrument::from_str)]
-    instrument: Instrument,
+    instrument: Option<Instrument>,
+    #[cfg(save)]
+    #[arg(short, long)]
+    output: Option<PathBuf>,
+    #[cfg(play)]
+    #[arg(short, long)]
+    silent: bool,
+    score: Score,
 }
 
-impl Args {
+#[derive(Clone)]
-    pub(super) fn instrument(&self) -> &<Instrument as Deref>::Target {
+#[cfg_attr(debug_assertions, derive(Debug))]
-        &self.instrument
+pub(super) struct Score(String);
+
+impl FromStr for Score {
+    type Err = Error;
+    fn from_str(value: &str) -> Result<Self, Self::Err> {
+        let maybe_a_path = Path::new(&value);
+        Ok(Score(if maybe_a_path.is_file() {
+            read_to_string(maybe_a_path)
+                .context("you gave me the path of a real file but reading it is hard!")?
+        } else {
+            value.to_owned() // hope it's a good one
+        }))
+    }
+}
+
+impl Deref for Score {
+    type Target = <String as Deref>::Target;
+    fn deref(&self) -> &Self::Target {
+        &self.0
     }
 }
 
 #[derive(Clone)]
+#[cfg_attr(debug_assertions, derive(Debug))]
 pub(super) struct Instrument(String);
 
 impl FromStr for Instrument {
@@ -26,7 +59,7 @@ impl FromStr for Instrument {
             read_to_string(maybe_a_path)
                 .context("you gave me the path of a real file but reading it is hard!")?
         } else {
-            value.to_owned() // hope it's good
+            value.to_owned() // hope it's a good one
         }))
     }
 }

src/main.rs

@@ -5,6 +5,7 @@ mod cli;
 
 fn main() -> Result<()> {
     let args = cli::Args::try_parse()?;
-    println!("got: {}", args.instrument());
+    #[cfg(debug_assertions)]
+    println!("{:?}", args);
     Ok(())
 }