figsoda · Jan 10, 2026 · Dec 31, 2025 · Dec 31, 2025 · Dec 31, 2025 · Dec 31, 2025
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -30,6 +30,7 @@ askalono.workspace = true
 bstr = "1.12.1"
 cargo = "0.93.0"
 chumsky = "=1.0.0-alpha.8"
+enum_dispatch = "0.3.13"
 expand = "0.3.0"
 flate2 = "1.1.5"
 heck = "0.5.0"
@@ -93,3 +94,6 @@ vendored = ["cargo/vendored-libgit2", "cargo/vendored-openssl"]
 lto = true
 panic = "abort"
 codegen-units = 1
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ["cfg(not_build)"] }
diff --git a/build.rs b/build.rs
@@ -8,15 +8,18 @@ use clap::{CommandFactory, ValueEnum};
 use clap_complete::{Shell, generate_to};
 use clap_mangen::Man;
 
-include!("src/cli.rs");
+mod cli {
+    include!("src/cli.rs");
+}
 
 fn main() {
     println!("cargo:rerun-if-env-changed=GEN_ARTIFACTS");
+    println!("cargo:rustc-cfg=not_build");
 
     if let Some(dir) = env::var_os("GEN_ARTIFACTS") {
         let out = &Path::new(&dir);
         create_dir_all(out).unwrap();
-        let cmd = &mut Opts::command();
+        let cmd = &mut cli::Opts::command();
 
         Man::new(cmd.clone())
             .render(&mut File::create(out.join("nix-init.1")).unwrap())

diff --git a/src/build.rs → src/builder.rs b/src/build.rs → src/builder.rs
@@ -1,37 +1,30 @@
 use std::fmt::{self, Display, Formatter};
 
-use parse_display::Display;
+use crate::cli::CargoVendor;
 
 #[derive(Clone, Copy)]
-pub enum BuildType {
+pub enum Builder {
     BuildGoModule,
     BuildPythonPackage {
         application: bool,
-        rust: Option<RustVendor>,
+        rust: Option<CargoVendor>,
     },
     BuildRustPackage {
-        vendor: RustVendor,
+        vendor: CargoVendor,
     },
     MkDerivation {
-        rust: Option<RustVendor>,
+        rust: Option<CargoVendor>,
     },
 }
 
-#[derive(Clone, Copy, Display)]
-#[display(style = "camelCase")]
-pub enum RustVendor {
-    FetchCargoVendor,
-    ImportCargoLock,
-}
-
-impl Display for BuildType {
+impl Display for Builder {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         match self {
-            BuildType::BuildGoModule => {
+            Builder::BuildGoModule => {
                 write!(f, "buildGoModule")?;
             }
 
-            BuildType::BuildPythonPackage { application, rust } => {
+            Builder::BuildPythonPackage { application, rust } => {
                 write!(
                     f,
                     "buildPython{}",
@@ -46,18 +39,18 @@ impl Display for BuildType {
                 }
             }
 
-            BuildType::BuildRustPackage { vendor } => {
+            Builder::BuildRustPackage { vendor } => {
                 write!(
                     f,
                     "buildRustPackage - {}",
                     match vendor {
-                        RustVendor::FetchCargoVendor => "cargoHash",
-                        RustVendor::ImportCargoLock => "cargoLock",
+                        CargoVendor::FetchCargoVendor => "cargoHash",
+                        CargoVendor::ImportCargoLock => "cargoLock",
                     }
                 )?;
             }
 
-            BuildType::MkDerivation { rust } => {
+            Builder::MkDerivation { rust } => {
                 write!(f, "stdenv.mkDerivation")?;
                 if let Some(rust) = rust {
                     write!(f, " + {rust}")?;

diff --git a/src/cli.rs b/src/cli.rs
@@ -1,11 +1,11 @@
 use std::path::PathBuf;
 
-use clap::Parser;
+use clap::{Parser, ValueEnum};
 
 /// Generate Nix packages with hash prefetching, license detection, and more
 /// https://github.com/nix-community/nix-init
 #[derive(Parser)]
-#[command(version, verbatim_doc_comment)]
+#[command(verbatim_doc_comment)]
 pub struct Opts {
     /// The path or directory to output the generated file to
     pub output: Option<PathBuf>,
@@ -14,6 +14,42 @@ pub struct Opts {
     #[arg(short, long)]
     pub url: Option<String>,
 
+    /// Specify the tag or revision
+    #[arg(long)]
+    pub rev: Option<String>,
+
+    /// Always fetch submodules when possible
+    ///
+    /// use --submodules=false to never fetch submodules
+    #[arg(short = 'S', long, num_args=0..=1, require_equals = true, default_missing_value = "true")]
+    pub submodules: Option<bool>,
+
+    /// Specify the version of the package, or print nix-init version if no arguments are present
+    #[arg(short = 'V', long)]
+    pub version: Option<Option<String>>,
+
+    /// Specify the pname
+    #[arg(long)]
+    pub pname: Option<String>,
+
+    /// Specify the builder
+    #[arg(long)]
+    pub builder: Option<BuilderFunction>,
+
+    /// Specify how the cargo dependencies are vendored
+    #[arg(long)]
+    pub cargo_vendor: Option<CargoVendor>,
+
+    /// Always overwrite files
+    ///
+    /// use --overwrite=false to never overwrite files
+    #[arg(short = 'y', long, num_args=0..=1, require_equals = true, default_missing_value = "true")]
+    pub overwrite: Option<bool>,
+
+    /// Don't prompt for anything (requires --url)
+    #[arg(long)]
+    pub headless: bool,
+
     /// Path to nixpkgs (in nix)
     ///
     /// Examples:
@@ -33,3 +69,25 @@ pub struct Opts {
     #[arg(short, long)]
     pub config: Option<PathBuf>,
 }
+
+#[derive(Clone, ValueEnum)]
+#[clap(rename_all = "camelCase")]
+pub enum BuilderFunction {
+    BuildGoModule,
+    BuildPythonApplication,
+    BuildPythonPackage,
+    BuildRustPackage,
+    MkDerivation,
+}
+
+#[derive(Clone, Copy, ValueEnum)]
+#[clap(rename_all = "camelCase")]
+#[cfg_attr(
+    not_build,
+    derive(parse_display::Display),
+    display(style = "camelCase")
+)]
+pub enum CargoVendor {
+    FetchCargoVendor,
+    ImportCargoLock,
+}
diff --git a/src/frontend/headless.rs b/src/frontend/headless.rs
@@ -0,0 +1,58 @@
+use std::path::{Path, PathBuf};
+
+use anyhow::{Result, bail};
+use tracing::error;
+
+use crate::{
+    builder::Builder,
+    fetcher::{Revisions, Version},
+    frontend::Frontend,
+    utils::by_name_path,
+};
+
+pub struct Headless;
+
+impl Frontend for Headless {
+    fn url(&mut self) -> Result<String> {
+        bail!("specifyi
10000
ng a URL with --url is required in headless mode");
+    }
+
+    fn rev(&mut self, revs: Option<Revisions>) -> Result<(String, Option<Version>)> {
+        Ok(if let Some(mut revs) = revs {
+            (revs.latest.clone(), revs.versions.remove(&revs.latest))
+        } else {
+            (String::new(), None)
+        })
+    }
+
+    fn fetch_submodules(&mut self) -> Result<bool> {
+        Ok(true)
+    }
+
+    fn version(&mut self, version: &str) -> Result<String> {
+        Ok(version.to_owned())
+    }
+
+    fn pname(&mut self, pname: Option<String>) -> Result<String> {
+        Ok(pname.unwrap_or_default())
+    }
+
+    fn builder(&mut self, builders: Vec<Builder>) -> Result<Builder> {
+        Ok(builders[0])
+    }
+
+    fn output(&mut self, pname: &str, builder: &Builder) -> Result<PathBuf> {
+        Ok(match by_name_path(pname, builder) {
+            Some(path) => path.into(),
+            None => PathBuf::from("."),
+        })
+    }
+
+    fn overwrite(&mut self, path: &Path) -> Result<bool> {
+        error!(
+            "path {} already exists, use --overwrite to overwrite to always overwrite files",
+            path.display()
+        );
+        Ok(false)
+    }
+}
diff --git a/src/frontend/mod.rs b/src/frontend/mod.rs
@@ -0,0 +1,55 @@
+mod headless;
+mod readline;
+
+use std::path::{Path, PathBuf};
+
+use anyhow::Result;
+use enum_dispatch::enum_dispatch;
+
+use crate::{
+    builder::Builder,
+    fetcher::{Revisions, Version},
+    frontend::{headless::Headless, readline::Readline},
+};
+
+#[enum_dispatch]
+pub trait Frontend {
+    fn url(&mut self) -> Result<String>;
+
+    fn rev(&mut self, revs: Option<Revisions>) -> Result<(String, Option<Version>)>;
+
+    fn fetch_submodules(&mut self) -> Result<bool>;
+
+    fn version(&mut self, version: &str) -> Result<String>;
+
+    fn pname(&mut self, pname: Option<String>) -> Result<String>;
+
+    fn builder(&mut self, builders: Vec<Builder>) -> Result<Builder>;
+
+    fn output(&mut self, pname: &str, builder: &Builder) -> Result<PathBuf>;
+
+    fn overwrite(&mut self, path: &Path) -> Result<bool>;
+}
+
+#[enum_dispatch(Frontend)]
+pub enum FrontendDispatch {
+    Headless(Headless),
+    Readline(Readline),
+}
+
+impl FrontendDispatch {
+    pub fn should_overwrite(&mut self, path: &Path, opt_overwrite: Option<bool>) -> Result<bool> {
+        match opt_overwrite {
+            Some(b) => Ok(b),
+            None => self.overwrite(path),
+        }
+    }
+}
+
+pub fn headless() -> FrontendDispatch {
+    Headless.into()
+}
+
+pub fn readline() -> Result<FrontendDispatch> {
+    Readline::new().map(Into::into)
+}