restructure cli for single file use

src/bng.rs

@@ -0,0 +1,2 @@
+mod instrument;
+mod score;

src/bng/instrument.rs

@@ -0,0 +1,5 @@
+use derived_deref::Deref;
+use fasteval::Instruction;
+
+#[derive(Deref)]
+pub struct Instrument(Instruction);

src/cli.rs

@@ -1,28 +1,48 @@
-use std::str::FromStr;
-cfg_if! {
-    if #[cfg(feature = "save")] {
-        use std::path::PathBuf;
-    }
-}
+use std::path::PathBuf;
 
-use cfg_if::cfg_if;
 use clap::Parser;
 
-mod instrument;
-mod score;
-pub use instrument::Instrument;
-pub use score::Score;
-
-#[derive(Parser)]
+/// Cli entry point
+#[derive(Clone, Parser)]
 #[cfg_attr(debug_assertions, derive(Debug))]
-pub(super) struct Args {
-    #[arg(short, long, value_parser = Instrument::from_str)]
-    instrument: Option<Instrument>,
-    #[cfg(feature = "save")]
-    #[arg(short, long)]
-    output: Option<PathBuf>,
-    #[cfg(feature = "play")]
-    #[arg(short, long)]
-    silent: bool,
-    score: Score,
+pub enum BngCli {
+    /// Play the song through default sink
+    Play(PlayOpts),
+    /// Export the song to a sound file
+    Export(ExportOpts),
+    /// List supported sound file extensions and instrument / song available expressions
+    #[command(subcommand)]
+    List(ListOpts),
+}
+
+/// [`BngCli`] "play" command options
+#[derive(Clone, Parser)]
+#[cfg_attr(debug_assertions, derive(Debug))]
+pub struct PlayOpts {
+    input: PathBuf,
+}
+
+/// [`BngCli`] "export" command options
+#[derive(Clone, Parser)]
+#[cfg_attr(debug_assertions, derive(Debug))]
+pub struct ExportOpts {
+    /// Input file (written song file)
+    input: PathBuf,
+    /// Output file (sound file)
+    output: PathBuf,
+}
+
+/// [`BngCli`] "list" command sub-commands
+#[derive(Clone, Parser)]
+#[cfg_attr(debug_assertions, derive(Debug))]
+pub enum ListOpts {
+    /// List supported sound file extensions to export songs
+    #[command(subcommand)]
+    Extensions,
+    /// List available math expressions for instrument definition
+    #[command(subcommand)]
+    Math,
+    /// List available score glyphs and their meaning
+    #[command(subcommand)]
+    Glyphs,
 }

src/cli/instrument.rs

@@ -1,21 +0,0 @@
-use std::{fs::read_to_string, path::Path, str::FromStr};
-
-use anyhow::{Context, Error};
-use derived_deref::Deref;
-
-#[derive(Clone, Deref)]
-#[cfg_attr(debug_assertions, derive(Debug))]
-pub struct Instrument(String);
-
-impl FromStr for Instrument {
-    type Err = Error;
-    fn from_str(value: &str) -> Result<Self, Self::Err> {
-        let maybe_a_path = Path::new(&value);
-        Ok(Instrument(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
-        }))
-    }
-}

src/cli/score.rs

@@ -1,21 +0,0 @@
-use std::{fs::read_to_string, path::Path, str::FromStr};
-
-use anyhow::{Context, Error};
-use derived_deref::Deref;
-
-#[derive(Clone, Deref)]
-#[cfg_attr(debug_assertions, derive(Debug))]
-pub 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
-        }))
-    }
-}

src/main.rs

@@ -1,6 +1,7 @@
 use anyhow::Result;
 use clap::Parser;
 
+mod bng;
 mod cli;
 
 fn main() -> Result<()> {