clap arg parser added + optional output file

Cargo.toml

@@ -4,4 +4,5 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
-inkwell = {version = "0.6.0", features = ["llvm18-1"]}
+clap = { version = "4.5.48", features = ["derive"] }
+inkwell = { version = "0.6.0", features = ["llvm18-1"] }

src/cmd_args.rs

@@ -0,0 +1,29 @@
+use std::sync::OnceLock;
+
+use clap::Parser;
+
+#[derive(Parser, Debug)]
+#[command(author, version, about, long_about = None)]
+pub struct CmdArgs {
+    /// Input file to process
+    #[arg(index = 1, value_name = "SOURCE_FILE")]
+    pub input_file: String,
+
+    /// Output file name
+    #[arg(short, long, value_name = "OUTPUT")]
+    pub output: Option<String>,
+}
+
+/// args singleton
+static ARGS: OnceLock<CmdArgs> = OnceLock::new();
+
+/// global read only access to args
+pub fn get() -> &'static CmdArgs {
+    ARGS.get_or_init(|| CmdArgs::parse())
+}
+
+/// just in case you don't need args but you want to make sure they are valid and return if not
+pub fn init() {
+    ARGS.set(CmdArgs::parse())
+        .expect("you are calling cmd_args::init() twice");
+}

src/main.rs

@@ -1,8 +1,10 @@
+mod cmd_args;
 mod code_generator;
 mod errors;
 mod lexer;
 mod macros;
 mod parser;
+
 use inkwell::context::Context;
 
 use crate::{
@@ -19,16 +21,9 @@ use std::{
     str::FromStr,
 };
 
-// TODO: use clap for cli purposes
-
 // WARNING: Fix all string allocations
 fn main() -> Result<()> {
-    let input: Vec<String> = std::env::args().collect();
-
-    match input.len() {
-        2 => run_file(&input[1])?,
-        _ => println!("Usage: Catalyst [filepath]"),
-    }
+    run_file(&cmd_args::get().input_file)?;
     Ok(())
 }
 
@@ -52,7 +47,11 @@ fn run_file(path: &str) -> Result<()> {
 
     let source_path = Path::new(path).parent().unwrap_or(Path::new("."));
 
-    let output_path = source_path.join(file_name);
+    let output_path = cmd_args::get()
+        .output
+        .clone()
+        .map(|x| PathBuf::from_str(&x).unwrap())
+        .unwrap_or(source_path.join(file_name));
 
     run(&bytes_str, output_path.to_str().unwrap())?;
     Ok(())