Add help and some command line args

build.rs

@@ -3,6 +3,11 @@ use roff::{Roff, bold, italic, roman};
 use std::{env, path::PathBuf};
 
 fn main() {
+    println!(
+        "cargo:rustc-env=TARGET={}",
+        std::env::var("TARGET").unwrap()
+    );
+    
     let page = Roff::new()
         .control("TH", ["SESH", "1"])
         .control("SH", ["NAME"])

src/builtins.rs

@@ -5,7 +5,14 @@
 pub const BUILTINS: [(
     &str,
     fn(args: Vec<String>, unsplit_args: String, state: &mut super::State) -> i32,
-); 4] = [("cd", cd), ("exit", exit), ("echo", echo), ("alias", alias)];
+    &str,
+); 5] = [
+    ("cd", cd, "[dir]"),
+    ("exit", exit, ""),
+    ("echo", echo, "[-e] [text ...]"),
+    ("alias", alias, "[name] [value]"),
+    ("help", help, ""),
+];
 
 /// Change the directory
 pub fn cd(args: Vec<String>, _: String, state: &mut super::State) -> i32 {
@@ -67,3 +74,20 @@ pub fn alias(args: Vec<String>, _: String, state: &mut super::State) -> i32 {
 
     0
 }
+
+/// Output help on builtins.
+pub fn help(_: Vec<String>, _: String, _: &mut super::State) -> i32 {
+    println!(
+        "sesh, version {} ({})",
+        env!("CARGO_PKG_VERSION"),
+        env!("TARGET")
+    );
+    println!("This provides a list of built-in shell commands.");
+    println!("Use `man sesh` to find out more about the shell in general.");
+    println!("Use `man -k' or `info' to find out more about commands not in this list.");
+    println!();
+    for builtin in BUILTINS {
+        println!("{} {}", builtin.0, builtin.2);
+    }
+    0
+}

src/main.rs

@@ -18,7 +18,14 @@ mod escapes;
 /// sesh is a shell designed to be as semantic to use as possible
 #[derive(Parser, Debug)]
 #[command(version, about, long_about = None)]
-struct Args {}
+struct Args {
+    /// Run an expression. This will not open an interactive shell. Takes precedence over --before
+    #[arg(long="run", short='c', default_value_t=("".to_string()))]
+    run_expr: String,
+    /// Run an expression before opening an interactive shell.
+    #[arg(long="before", short='b', default_value_t=("".to_string()))]
+    run_before: String,
+}
 
 /// A single shell variable
 #[derive(Clone, Debug, PartialEq, Eq)]
@@ -274,6 +281,8 @@ fn write_prompt(state: State) -> Result<(), Box<dyn std::error::Error>> {
 
 #[allow(clippy::arc_with_non_send_sync)]
 fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let options = Args::parse();
+
     let mut state = State {
         env: Arc::new(Mutex::new(std::env::vars_os())),
         shell_env: Vec::new(),
@@ -292,6 +301,43 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         value: "> ".to_string(),
     });
 
+    let mut interactive = true;
+
+    if !options.run_expr.is_empty() {
+        interactive = false;
+        state.shell_env.push(ShellVar {
+            name: "INTERACTIVE".to_string(),
+            value: "false".to_string(),
+        });
+    } else {
+        state.shell_env.push(ShellVar {
+            name: "INTERACTIVE".to_string(),
+            value: "true".to_string(),
+        });
+    }
+
+    let rc = std::fs::read(std::env::home_dir().unwrap().join(".seshrc"));
+    if rc.is_err() {
+        println!("sesh: reading ~/.seshrc failed: {}", rc.unwrap_err());
+        println!("sesh: not running .seshrc")
+    } else {
+        let rc = String::from_utf8(rc.unwrap());
+        if rc.is_err() {
+            println!("sesh: reading ~/.seshrc failed: not valid UTF-8");
+            println!("sesh: not running .seshrc")
+        } else {
+            let rc = rc.unwrap();
+            eval(&rc, &mut state);
+        }
+    }
+
+    if !interactive {
+        eval(&options.run_expr, &mut state);
+        return Ok(());
+    } else if !options.run_before.is_empty() {
+        eval(&options.run_before, &mut state)
+    }
+
     let ctrlc_cont = Arc::new(RwLock::new(false));
     let cc2 = ctrlc_cont.clone();