Implemented the autocmd builtin, which allows you to register hooks for certain shell events.

src/builtin/autocmd.rs

@@ -0,0 +1,91 @@
+use regex::Regex;
+
+use crate::{
+  getopt::{Opt, OptSpec, get_opts_from_tokens}, libsh::error::{ShErr, ShErrKind, ShResult, ShResultExt}, parse::{NdRule, Node, execute::prepare_argv}, state::{self, AutoCmd, AutoCmdKind, write_logic}
+};
+
+pub struct AutoCmdOpts {
+	pattern: Option<Regex>,
+	clear: bool
+}
+fn autocmd_optspec() -> [OptSpec;2] {
+	[
+		OptSpec {
+			opt: Opt::Short('p'),
+			takes_arg: true
+		},
+		OptSpec {
+			opt: Opt::Short('c'),
+			takes_arg: false
+		}
+	]
+}
+
+pub fn get_autocmd_opts(opts: &[Opt]) -> ShResult<AutoCmdOpts> {
+	let mut autocmd_opts = AutoCmdOpts {
+		pattern: None,
+		clear: false
+	};
+
+	let mut opts = opts.iter();
+	while let Some(arg) = opts.next() {
+		match arg {
+			Opt::ShortWithArg('p', arg) => {
+				autocmd_opts.pattern = Some(Regex::new(arg).map_err(|e| ShErr::simple(ShErrKind::ExecFail, format!("invalid regex for -p: {}", e)))?);
+			}
+			Opt::Short('c') => {
+				autocmd_opts.clear = true;
+			}
+			_ => {
+				return Err(ShErr::simple(ShErrKind::ExecFail, format!("unexpected option: {}", arg)));
+			}
+		}
+	}
+
+	Ok(autocmd_opts)
+}
+
+pub fn autocmd(node: Node) -> ShResult<()> {
+  let span = node.get_span();
+  let NdRule::Command {
+    assignments: _,
+    argv,
+  } = node.class
+  else {
+    unreachable!()
+  };
+
+	let (argv,opts) = get_opts_from_tokens(argv, &autocmd_optspec()).promote_err(span.clone())?;
+	let autocmd_opts = get_autocmd_opts(&opts).promote_err(span.clone())?;
+  let mut argv = prepare_argv(argv)?;
+  if !argv.is_empty() { argv.remove(0); }
+	let mut args = argv.iter();
+
+	let Some(autocmd_kind) = args.next() else {
+		return Err(ShErr::at(ShErrKind::ExecFail, span, "expected an autocmd kind".to_string()));
+	};
+
+	let Ok(autocmd_kind) = autocmd_kind.0.parse::<AutoCmdKind>() else {
+		return Err(ShErr::at(ShErrKind::ExecFail, autocmd_kind.1.clone(), format!("invalid autocmd kind: {}", autocmd_kind.0)));
+	};
+
+	if autocmd_opts.clear {
+		write_logic(|l| l.clear_autocmds(autocmd_kind));
+		state::set_status(0);
+		return Ok(());
+	}
+
+	let Some(autocmd_cmd) = args.next() else {
+		return Err(ShErr::at(ShErrKind::ExecFail, span, "expected an autocmd command".to_string()));
+	};
+
+	let autocmd = AutoCmd {
+		pattern: autocmd_opts.pattern,
+		command: autocmd_cmd.0.clone(),
+	};
+
+	write_logic(|l| l.insert_autocmd(autocmd_kind, autocmd));
+
+  state::set_status(0);
+  Ok(())
+}

src/builtin/cd.rs

@@ -44,7 +44,7 @@ pub fn cd(node: Node) -> ShResult<()> {
       .labeled(cd_span.clone(), format!("cd: Not a directory '{}'", new_dir.display().fg(next_color()))));
   }
 
-  if let Err(e) = env::set_current_dir(new_dir) {
+  if let Err(e) = state::change_dir(new_dir) {
     return Err(ShErr::new(ShErrKind::ExecFail, span.clone())
       .labeled(cd_span.clone(), format!("cd: Failed to change directory: '{}'", e.fg(Color::Red))));
   }

src/builtin/dirstack.rs

@@ -52,7 +52,7 @@ fn change_directory(target: &PathBuf, blame: Span) -> ShResult<()> {
     );
   }
 
-  if let Err(e) = env::set_current_dir(target) {
+  if let Err(e) = state::change_dir(target) {
     return Err(
       ShErr::at(ShErrKind::ExecFail, blame, format!("Failed to change directory: '{}'", e.fg(Color::Red)))
     );

src/builtin/keymap.rs

@@ -1,5 +1,5 @@
 use crate::{
-  expand::expand_keymap, getopt::{Opt, OptSpec, get_opts_from_tokens}, libsh::error::{ShErr, ShErrKind, ShResult, ShResultExt}, parse::{NdRule, Node, execute::prepare_argv}, prelude::*, readline::{keys::KeyEvent, vimode::ModeReport}, state::{self, write_logic}
+  expand::expand_keymap, getopt::{Opt, OptSpec, get_opts_from_tokens}, libsh::error::{ShErr, ShErrKind, ShResult, ShResultExt}, parse::{NdRule, Node, execute::prepare_argv}, prelude::*, readline::keys::KeyEvent, state::{self, write_logic}
 };
 
 bitflags! {

src/builtin/mod.rs

@@ -26,13 +26,14 @@ pub mod arrops;
 pub mod intro;
 pub mod getopts;
 pub mod keymap;
+pub mod autocmd;
 
-pub const BUILTINS: [&str; 46] = [
+pub const BUILTINS: [&str; 47] = [
   "echo", "cd", "read", "export", "local", "pwd", "source", "shift", "jobs", "fg", "bg", "disown",
   "alias", "unalias", "return", "break", "continue", "exit", "zoltraak", "shopt", "builtin",
   "command", "trap", "pushd", "popd", "dirs", "exec", "eval", "true", "false", ":", "readonly",
   "unset", "complete", "compgen", "map", "pop", "fpop", "push", "fpush", "rotate", "wait", "type",
-	"getopts", "keymap", "read_key"
+	"getopts", "keymap", "read_key", "autocmd"
 ];
 
 pub fn true_builtin() -> ShResult<()> {

src/builtin/read.rs

@@ -4,7 +4,6 @@ use nix::{
   libc::{STDIN_FILENO, STDOUT_FILENO},
   unistd::{isatty, read, write},
 };
-use yansi::Paint;
 
 use crate::{
   expand::expand_keymap, getopt::{Opt, OptSpec, get_opts_from_tokens}, libsh::{error::{ShErr, ShErrKind, ShResult, ShResultExt}, sys::TTY_FILENO}, parse::{NdRule, Node, execute::prepare_argv}, procio::borrow_fd, readline::term::{KeyReader, PollReader, RawModeGuard}, state::{self, VarFlags, VarKind, read_vars, write_vars}