feat: add --help/-h flags and CLI list argument parsing

README.md

@@ -97,6 +97,12 @@ No flags needed. The first arg is code (or a file path — auto-detected). Remai
 ilo 'dbl x:n>n;s=*x 2;+s 0 tot p:n q:n r:n>n;s=*p q;t=*s r;+s t' tot 10 20 30
 ```
 
+**Pass list arguments** with commas:
+```bash
+ilo 'f xs:L n>n;len xs' 1,2,3         # → 3
+ilo 'f xs:L t>t;xs.0' 'a,b,c'         # → a
+```
+
 **Run from a file:**
 ```bash
 ilo program.ilo 10 20 30
@@ -105,6 +111,7 @@ ilo program.ilo 10 20 30
 **Help & language spec:**
 ```bash
 ilo help                     # usage and examples
+ilo -h                       # same as ilo help
 ilo help lang                # print the full language specification
 ```
 

SPEC.md

@@ -142,6 +142,12 @@ xs.0     # first element
 xs.2     # third element
 ```
 
+**CLI list arguments:** Pass lists from the command line with commas (brackets also accepted):
+```
+ilo 'f xs:L n>n;len xs' 1,2,3       → 3
+ilo 'f xs:L t>t;xs.0' 'a,b,c'       → a
+```
+
 ---
 
 ## Statements

src/main.rs

@@ -13,7 +13,7 @@ fn main() {
 
     if args.len() < 2 {
         eprintln!("Usage: ilo <file-or-code> [args... | --run func args... | --bench func args... | --emit python]");
-        eprintln!("       ilo help          Show usage and examples");
+        eprintln!("       ilo help | -h     Show usage and examples");
         eprintln!("       ilo help lang     Show language specification");
         std::process::exit(1);
     }
@@ -23,7 +23,7 @@ fn main() {
         std::process::exit(0);
     }
 
-    if args[1] == "help" {
+    if args[1] == "help" || args[1] == "--help" || args[1] == "-h" {
         if args.len() > 2 && args[2] == "lang" {
             print!("{}", include_str!("../SPEC.md"));
         } else {
@@ -45,6 +45,7 @@ fn main() {
             println!("  --run-llvm       LLVM JIT (requires --features llvm build)\n");
             println!("Examples:");
             println!("  ilo 'f x:n>n;*x 2' 5             Define and call f(5) → 10");
+            println!("  ilo 'f xs:L n>n;len xs' 1,2,3     Pass a list → 3");
             println!("  ilo program.ilo 10 20             Run file with arguments");
             println!("  ilo 'f x:n>n;*x 2' --emit python Transpile to Python");
         }
@@ -630,6 +631,20 @@ print(f"__NS__={{_per}}")
 }
 
 fn parse_cli_arg(s: &str) -> interpreter::Value {
+    // Bracketed list: [1,2,3] or []
+    if s.starts_with('[') && s.ends_with(']') {
+        let inner = s[1..s.len()-1].trim();
+        if inner.is_empty() {
+            return interpreter::Value::List(vec![]);
+        }
+        let items = inner.split(',').map(|part| parse_cli_arg(part.trim())).collect();
+        return interpreter::Value::List(items);
+    }
+    // Bare comma list: 1,2,3
+    if s.contains(',') {
+        let items = s.split(',').map(|part| parse_cli_arg(part.trim())).collect();
+        return interpreter::Value::List(items);
+    }
     if let Ok(n) = s.parse::<f64>()
         && n.is_finite() {
             return interpreter::Value::Number(n);

tests/eval_inline.rs

@@ -221,6 +221,70 @@ fn inline_bench_mode() {
 
 // --- Help ---
 
+#[test]
+fn help_flag_shows_usage() {
+    let out = ilo()
+        .args(["--help"])
+        .output()
+        .expect("failed to run ilo");
+    assert!(out.status.success());
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    assert!(stdout.contains("Backends:"), "expected backends section, got: {}", stdout);
+}
+
+#[test]
+fn help_short_flag_shows_usage() {
+    let out = ilo()
+        .args(["-h"])
+        .output()
+        .expect("failed to run ilo");
+    assert!(out.status.success());
+    let stdout = String::from_utf8_lossy(&out.stdout);
+    assert!(stdout.contains("Backends:"), "expected backends section, got: {}", stdout);
+}
+
+// --- List arguments ---
+
+#[test]
+fn inline_list_arg_bracketed() {
+    let out = ilo()
+        .args(["f xs:L n>n;len xs", "[1,2,3]"])
+        .output()
+        .expect("failed to run ilo");
+    assert!(out.status.success(), "stderr: {}", String::from_utf8_lossy(&out.stderr));
+    assert_eq!(String::from_utf8_lossy(&out.stdout).trim(), "3");
+}
+
+#[test]
+fn inline_list_arg_bracketed_index() {
+    let out = ilo()
+        .args(["f xs:L n>n;xs.0", "[10,20,30]"])
+        .output()
+        .expect("failed to run ilo");
+    assert!(out.status.success(), "stderr: {}", String::from_utf8_lossy(&out.stderr));
+    assert_eq!(String::from_utf8_lossy(&out.stdout).trim(), "10");
+}
+
+#[test]
+fn inline_list_arg_bare_comma() {
+    let out = ilo()
+        .args(["f xs:L n>n;len xs", "1,2,3"])
+        .output()
+        .expect("failed to run ilo");
+    assert!(out.status.success(), "stderr: {}", String::from_utf8_lossy(&out.stderr));
+    assert_eq!(String::from_utf8_lossy(&out.stdout).trim(), "3");
+}
+
+#[test]
+fn inline_list_arg_bare_comma_index() {
+    let out = ilo()
+        .args(["f xs:L n>n;xs.0", "10,20,30"])
+        .output()
+        .expect("failed to run ilo");
+    assert!(out.status.success(), "stderr: {}", String::from_utf8_lossy(&out.stderr));
+    assert_eq!(String::from_utf8_lossy(&out.stdout).trim(), "10");
+}
+
 #[test]
 fn help_shows_usage() {
     let out = ilo()