move nixlang impls to their own directory tree

src/args.rs

@@ -56,10 +56,15 @@ pub struct AppendCmd {
     pub value: Arc<str>,
 }
 
+#[derive(Debug, Clone, PartialEq, clap::Parser)]
+pub struct DeltaCmd {}
+
 #[derive(Debug, Clone, PartialEq, clap::Subcommand)]
 #[command(flatten_help = true)]
 pub enum Subcommand {
     Append(AppendCmd),
+    // TODO: rename
+    Delta(DeltaCmd),
 }
 
 #[derive(Debug, Clone, PartialEq, clap::Parser)]
@@ -70,6 +75,7 @@ pub struct Args {
     #[arg(long, global(true), default_value = "auto")]
     pub color: ColorChoice,
 
+    // FIXME: default to /etc/configuration.nix, or something?
     #[arg(long, global(true), default_value = "./configuration.nix")]
     pub file: Arc<OsStr>,
 

src/lib.rs

@@ -34,7 +34,7 @@ pub(crate) mod prelude {
 use prelude::*;
 
 pub mod args;
-pub use args::{AppendCmd, Args};
+pub use args::{AppendCmd, Args, DeltaCmd};
 mod color;
 pub use color::{_CLI_ENABLE_COLOR, SHOULD_COLOR};
 pub mod line;
@@ -49,6 +49,11 @@ use crate::source::SourceFile;
 
 pub const ASCII_WHITESPACE: &[char] = &['\t', '\n', '\x0C', '\r', ' '];
 
+#[tracing::instrument(level = "debug")]
+pub fn do_delta(args: Arc<Args>, delta_args: DeltaCmd) -> Result<(), BoxDynError> {
+    todo!();
+}
+
 #[tracing::instrument(level = "debug")]
 pub fn do_append(args: Arc<Args>, append_args: AppendCmd) -> Result<(), BoxDynError> {
     let filepath = Path::new(&args.file);

src/main.rs

@@ -26,10 +26,13 @@ fn main_wrapped() -> Result<(), Box<dyn StdError + Send + Sync + 'static>> {
 
     tracing::debug!("Parsed command-line arguments: {args:?}");
 
-    use dynix::args::Subcommand::*;
-    match &args.subcommand {
-        Append(append_args) => dynix::do_append(args.clone(), append_args.clone())?,
-    };
+    {
+        use dynix::args::Subcommand::*;
+        match &args.subcommand {
+            Append(append_args) => dynix::do_append(args.clone(), append_args.clone())?,
+            Delta(delta_args) => dynix::do_delta(args.clone(), delta_args.clone())?,
+        };
+    }
 
     Ok(())
 }