Early implementation of scripting elements

src/builtin/alias.rs

@@ -6,12 +6,16 @@ pub fn alias(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 		let argv = argv.drop_first();
 		let mut argv_iter = argv.into_iter();
 		while let Some(arg) = argv_iter.next() {
-			let arg_raw = arg.to_string();
+			let arg_raw = shenv.input_slice(arg.span()).to_string();
 			if let Some((alias,body)) = arg_raw.split_once('=') {
+				log!(DEBUG, "{:?}",arg.span());
+				log!(DEBUG, arg_raw);
+				log!(DEBUG, body);
 				let clean_body = trim_quotes(&body);
+				log!(DEBUG, clean_body);
 				shenv.logic_mut().set_alias(alias, &clean_body);
 			} else {
-				return Err(ShErr::full(ShErrKind::SyntaxErr, "Expected an assignment in alias args", arg.span().clone()))
+				return Err(ShErr::full(ShErrKind::SyntaxErr, "Expected an assignment in alias args", shenv.get_input(), arg.span().clone()))
 			}
 		}
 	} else { unreachable!() }

src/builtin/cd.rs

@@ -5,7 +5,7 @@ pub fn cd(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 	if let NdRule::Command { argv, redirs: _ } = rule {
 		let mut argv_iter = argv.into_iter();
 		argv_iter.next(); // Ignore 'cd'
-		let dir_raw = argv_iter.next().map(|arg| arg.to_string()).unwrap_or(std::env::var("HOME")?);
+		let dir_raw = argv_iter.next().map(|arg| shenv.input_slice(arg.span()).into()).unwrap_or(std::env::var("HOME")?);
 		let dir = PathBuf::from(&dir_raw);
 		std::env::set_current_dir(dir)?;
 		shenv.vars_mut().export("PWD",&dir_raw);

src/builtin/control_flow.rs

@@ -0,0 +1,20 @@
+use crate::prelude::*;
+
+pub fn sh_flow(node: Node, shenv: &mut ShEnv, kind: ShErrKind) -> ShResult<()> {
+	let rule = node.into_rule();
+	let mut code: i32 = 0;
+	if let NdRule::Command { argv, redirs } = rule {
+		let mut argv_iter = argv.into_iter();
+		while let Some(arg) = argv_iter.next() {
+			if let Ok(code_arg) = shenv.input_slice(arg.span()).parse() {
+				code = code_arg
+			}
+		}
+	} else { unreachable!() }
+	shenv.set_code(code);
+	// Our control flow keywords are used as ShErrKinds
+	// This design will halt the execution flow and start heading straight back upward
+	// Function returns and loop breaks/continues will be caught in the proper context to allow
+	// Execution to continue at the proper return point.
+	Err(ShErr::simple(kind, ""))
+}

src/builtin/export.rs

@@ -6,7 +6,7 @@ pub fn export(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 		let mut argv_iter = argv.into_iter();
 		argv_iter.next(); // Ignore 'export'
 		while let Some(arg) = argv_iter.next() {
-			let arg_raw = arg.to_string();
+			let arg_raw = shenv.input_slice(arg.span()).to_string();
 			if let Some((var,val)) = arg_raw.split_once('=') {
 				shenv.vars_mut().export(var, val);
 			} else {

src/builtin/jobctl.rs

@@ -14,6 +14,7 @@ pub fn continue_job(node: Node, shenv: &mut ShEnv, fg: bool) -> ShResult<()> {
 				ShErr::full(
 					ShErrKind::InternalErr,
 					format!("Somehow called {} with an existing foreground job",cmd),
+					shenv.get_input(),
 					blame
 				)
 			)
@@ -22,11 +23,11 @@ pub fn continue_job(node: Node, shenv: &mut ShEnv, fg: bool) -> ShResult<()> {
 		let curr_job_id = if let Some(id) = read_jobs(|j| j.curr_job()) {
 			id
 		} else {
-			return Err(ShErr::full(ShErrKind::ExecFail, "No jobs found", blame))
+			return Err(ShErr::full(ShErrKind::ExecFail, "No jobs found", shenv.get_input(), blame))
 		};
 
 		let tabid = match argv_s.next() {
-			Some(arg) => parse_job_id(&arg, blame.clone())?,
+			Some(arg) => parse_job_id(&arg, blame.clone(),shenv)?,
 			None => curr_job_id
 		};
 
@@ -36,7 +37,14 @@ pub fn continue_job(node: Node, shenv: &mut ShEnv, fg: bool) -> ShResult<()> {
 			if query_result.is_some() {
 				Ok(j.remove_job(id.clone()).unwrap())
 			} else {
-				Err(ShErr::full(ShErrKind::ExecFail, format!("Job id `{}' not found", tabid), blame))
+				Err(
+					ShErr::full(
+						ShErrKind::ExecFail,
+						format!("Job id `{}' not found", tabid),
+						shenv.get_input(),
+						blame
+					)
+				)
 			}
 		})?;
 
@@ -54,7 +62,7 @@ pub fn continue_job(node: Node, shenv: &mut ShEnv, fg: bool) -> ShResult<()> {
 	Ok(())
 }
 
-fn parse_job_id(arg: &str, blame: Span) -> ShResult<usize> {
+fn parse_job_id(arg: &str, blame: Rc<RefCell<Span>>, shenv: &mut ShEnv) -> ShResult<usize> {
 	if arg.starts_with('%') {
 		let arg = arg.strip_prefix('%').unwrap();
 		if arg.chars().all(|ch| ch.is_ascii_digit()) {
@@ -66,7 +74,14 @@ fn parse_job_id(arg: &str, blame: Span) -> ShResult<usize> {
 			});
 			match result {
 				Some(id) => Ok(id),
-				None => Err(ShErr::full(ShErrKind::InternalErr,"Found a job but no table id in parse_job_id()",blame))
+				None => Err(
+					ShErr::full(
+						ShErrKind::InternalErr,
+						"Found a job but no table id in parse_job_id()",
+						shenv.get_input(),
+						blame
+					)
+				)
 			}
 		}
 	} else if arg.chars().all(|ch| ch.is_ascii_digit()) {
@@ -86,10 +101,24 @@ fn parse_job_id(arg: &str, blame: Span) -> ShResult<usize> {
 
 		match result {
 			Some(id) => Ok(id),
-			None => Err(ShErr::full(ShErrKind::InternalErr,"Found a job but no table id in parse_job_id()",blame))
+			None => Err(
+				ShErr::full(
+					ShErrKind::InternalErr,
+					"Found a job but no table id in parse_job_id()",
+					shenv.get_input(),
+					blame
+				)
+			)
 		}
 	} else {
-		Err(ShErr::full(ShErrKind::SyntaxErr,format!("Invalid fd arg: {}", arg),blame))
+		Err(
+			ShErr::full(
+				ShErrKind::SyntaxErr,
+				format!("Invalid fd arg: {}", arg),
+				shenv.get_input(),
+				blame
+			)
+		)
 	}
 }
 
@@ -100,10 +129,17 @@ pub fn jobs(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 
 		let mut flags = JobCmdFlags::empty();
 		while let Some(arg) = argv.next() {
-			let arg_s = arg.to_string();
+			let arg_s = shenv.input_slice(arg.span());
 			let mut chars = arg_s.chars().peekable();
 			if chars.peek().is_none_or(|ch| *ch != '-') {
-				return Err(ShErr::full(ShErrKind::SyntaxErr, "Invalid flag in jobs call", arg.span().clone()))
+				return Err(
+					ShErr::full(
+						ShErrKind::SyntaxErr,
+						"Invalid flag in jobs call",
+						shenv.get_input(),
+						arg.span()
+					)
+				)
 			}
 			chars.next();
 			while let Some(ch) = chars.next() {
@@ -113,7 +149,14 @@ pub fn jobs(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 					'n' => JobCmdFlags::NEW_ONLY,
 					'r' => JobCmdFlags::RUNNING,
 					's' => JobCmdFlags::STOPPED,
-					_ => return Err(ShErr::full(ShErrKind::SyntaxErr, "Invalid flag in jobs call", arg.span().clone()))
+					_ => return Err(
+						ShErr::full(
+							ShErrKind::SyntaxErr,
+							"Invalid flag in jobs call",
+							shenv.get_input(),
+							arg.span()
+						)
+					)
 
 				};
 				flags |= flag

src/builtin/mod.rs

@@ -5,8 +5,9 @@ pub mod export;
 pub mod jobctl;
 pub mod read;
 pub mod alias;
+pub mod control_flow;
 
-pub const BUILTINS: [&str;9] = [
+pub const BUILTINS: [&str;13] = [
 	"echo",
 	"cd",
 	"pwd",
@@ -15,5 +16,9 @@ pub const BUILTINS: [&str;9] = [
 	"bg",
 	"jobs",
 	"read",
-	"alias"
+	"alias",
+	"exit",
+	"continue",
+	"return",
+	"break",
 ];

src/builtin/read.rs

@@ -27,7 +27,8 @@ pub fn read_builtin(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 				shenv.vars_mut().set_var(&first_var.to_string(), &read_input);
 			}
 			*/
-			shenv.vars_mut().set_var(&var.to_string(), &read_input);
+			let var_name = shenv.input_slice(var.span()).to_string();
+			shenv.vars_mut().set_var(&var_name, &read_input);
 		}
 	} else {
 		unreachable!()

src/execute/ifthen.rs

@@ -0,0 +1,28 @@
+use crate::{parse::parse::SynTree, prelude::*};
+
+pub fn exec_if(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
+	let rule = node.into_rule();
+	if let NdRule::IfThen { cond_blocks, else_block } = rule {
+		if shenv.ctx().flags().contains(ExecFlags::NO_FORK) {
+			shenv.ctx_mut().unset_flag(ExecFlags::NO_FORK);
+		}
+		let mut cond_blocks = cond_blocks.into_iter();
+
+		while let Some(block) = cond_blocks.next() {
+			let cond = block.0;
+			let body = block.1;
+			let ast = SynTree::from_vec(cond);
+			Executor::new(ast,shenv).walk()?;
+			if shenv.get_code() == 0 {
+				let ast = SynTree::from_vec(body);
+				return Executor::new(ast,shenv).walk()
+			}
+		}
+
+		if let Some(block) = else_block {
+			let ast = SynTree::from_vec(block);
+			Executor::new(ast,shenv).walk()?;
+		}
+	} else { unreachable!() }
+	Ok(())
+}

src/execute/mod.rs

@@ -4,6 +4,33 @@ use shellenv::jobs::{ChildProc, JobBldr};
 
 use crate::{builtin::export::export, libsh::{error::Blame, sys::{execvpe, get_bin_path}, utils::{ArgVec, StrOps}}, parse::{lex::Token, parse::{CmdGuard, NdFlag, Node, NdRule, SynTree}}, prelude::*};
 
+pub mod ifthen;
+
+pub fn exec_input<S: Into<String>>(input: S, shenv: &mut ShEnv) -> ShResult<()> {
+	let input = input.into();
+	shenv.new_input(&input);
+	log!(INFO, "New input: {:?}", input);
+
+	let token_stream = Lexer::new(input,shenv).lex();
+
+	let token_stream = expand_aliases(token_stream, shenv);
+	for token in &token_stream {
+		log!(DEBUG, token);
+		log!(DEBUG, "{}",token.as_raw(shenv));
+	}
+
+	let syn_tree = Parser::new(token_stream,shenv).parse()?;
+	if let Err(e) = Executor::new(syn_tree, shenv).walk() {
+		if let ShErrKind::CleanExit = e.kind() {
+			let code = shenv.get_code();
+			sh_quit(code);
+		} else {
+			return Err(e.into())
+		}
+	}
+	Ok(())
+}
+
 pub struct Executor<'a> {
 	ast: SynTree,
 	shenv: &'a mut ShEnv
@@ -16,10 +43,9 @@ impl<'a> Executor<'a> {
 	pub fn walk(&mut self) -> ShResult<()> {
 		log!(DEBUG, "Starting walk");
 		while let Some(node) = self.ast.next_node() {
-			let span = node.span();
 			if let NdRule::CmdList { cmds } = node.clone().into_rule() {
 				log!(TRACE, "{:?}", cmds);
-				exec_list(cmds, self.shenv).try_blame(span)?
+				exec_list(cmds, self.shenv).try_blame(node.as_raw(self.shenv),node.span())?
 			} else { unreachable!() }
 		}
 		Ok(())
@@ -33,6 +59,7 @@ fn exec_list(list: Vec<(Option<CmdGuard>, Node)>, shenv: &mut ShEnv) -> ShResult
 		let guard = cmd_info.0;
 		let cmd = cmd_info.1;
 		let span = cmd.span();
+		let cmd_raw = cmd.as_raw(shenv);
 
 		if let Some(guard) = guard {
 			let code = shenv.get_code();
@@ -47,11 +74,12 @@ fn exec_list(list: Vec<(Option<CmdGuard>, Node)>, shenv: &mut ShEnv) -> ShResult
 		}
 		log!(TRACE, "{:?}", *cmd.rule());
 		match *cmd.rule() {
-			NdRule::Command {..} => dispatch_command(cmd, shenv).try_blame(span)?,
-			NdRule::Subshell {..} => exec_subshell(cmd,shenv).try_blame(span)?,
-			NdRule::FuncDef {..} => exec_funcdef(cmd,shenv).try_blame(span)?,
-			NdRule::Assignment {..} => exec_assignment(cmd,shenv).try_blame(span)?,
-			NdRule::Pipeline {..} => exec_pipeline(cmd, shenv).try_blame(span)?,
+			NdRule::Command {..} => dispatch_command(cmd, shenv).try_blame(cmd_raw, span)?,
+			NdRule::Subshell {..} => exec_subshell(cmd,shenv).try_blame(cmd_raw, span)?,
+			NdRule::IfThen {..} => ifthen::exec_if(cmd, shenv).try_blame(cmd_raw, span)?,
+			NdRule::FuncDef {..} => exec_funcdef(cmd,shenv).try_blame(cmd_raw, span)?,
+			NdRule::Assignment {..} => exec_assignment(cmd,shenv).try_blame(cmd_raw, span)?,
+			NdRule::Pipeline {..} => exec_pipeline(cmd, shenv).try_blame(cmd_raw, span)?,
 			_ => unimplemented!()
 		}
 	}
@@ -64,7 +92,7 @@ fn dispatch_command(mut node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 	let mut is_subsh = false;
 	if let NdRule::Command { ref mut argv, redirs: _ } = node.rule_mut() {
 		*argv = expand_argv(argv.to_vec(), shenv);
-		let cmd = argv.first().unwrap().to_string();
+		let cmd = argv.first().unwrap().as_raw(shenv);
 		if shenv.logic().get_function(&cmd).is_some() {
 			is_func = true;
 		} else if node.flags().contains(NdFlag::BUILTIN) {
@@ -91,33 +119,32 @@ fn exec_func(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 	let rule = node.into_rule();
 	if let NdRule::Command { argv, redirs } = rule {
 		let mut argv_iter = argv.into_iter();
-		let func_name = argv_iter.next().unwrap().to_string();
+		let func_name = argv_iter.next().unwrap().as_raw(shenv);
 		let body = shenv.logic().get_function(&func_name).unwrap().to_string();
 		let snapshot = shenv.clone();
 		shenv.vars_mut().reset_params();
 		while let Some(arg) = argv_iter.next() {
-			shenv.vars_mut().bpush_arg(&arg.to_string());
+			let arg_raw = shenv.input_slice(arg.span()).to_string();
+			shenv.vars_mut().bpush_arg(&arg_raw);
 		}
 		shenv.collect_redirs(redirs);
 
-		let lex_input = Rc::new(body);
-		let tokens = Lexer::new(lex_input).lex();
-		match Parser::new(tokens).parse() {
-			Ok(syn_tree) => {
-				match Executor::new(syn_tree, shenv).walk() {
-					Ok(_) => { /* yippee */ }
-					Err(e) => {
-						*shenv = snapshot;
-						return Err(e.into())
-					}
-				}
+		match exec_input(body, shenv) {
+			Ok(()) => {
+				*shenv = snapshot;
+				return Ok(())
+			}
+			Err(e) if e.kind() == ShErrKind::FuncReturn => {
+				let code = shenv.get_code();
+				*shenv = snapshot;
+				shenv.set_code(code);
+				return Ok(())
 			}
 			Err(e) => {
 				*shenv = snapshot;
 				return Err(e.into())
 			}
 		}
-		*shenv = snapshot;
 	}
 	Ok(())
 }
@@ -125,9 +152,9 @@ fn exec_func(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 fn exec_funcdef(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 	let rule = node.into_rule();
 	if let NdRule::FuncDef { name, body } = rule {
-		let name_raw = name.to_string();
+		let name_raw = name.as_raw(shenv);
 		let name = name_raw.trim_end_matches("()");
-		let body_raw = body.to_string();
+		let body_raw = body.as_raw(shenv);
 		let body = body_raw[1..body_raw.len() - 1].trim();
 
 		shenv.logic_mut().set_function(name, body);
@@ -148,26 +175,18 @@ fn exec_subshell(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 				exit(1);
 			}
 			for arg in argv {
-				shenv.vars_mut().bpush_arg(&arg.to_string());
+				let arg_raw = &arg.as_raw(shenv);
+				shenv.vars_mut().bpush_arg(arg_raw);
 			}
-			let body_raw = body.to_string();
-			let lexer_input = Rc::new(
-					body_raw[1..body_raw.len() - 1].to_string()
-			);
-			let token_stream = Lexer::new(lexer_input).lex();
-			match Parser::new(token_stream).parse() {
-				Ok(syn_tree) => {
-					if let Err(e) = Executor::new(syn_tree, shenv).walk() {
-						write_err(e)?;
-						exit(1);
-					}
-				}
+			let body_raw = body.as_raw(shenv);
+
+			match exec_input(body_raw, shenv) {
+				Ok(()) => sh_quit(0),
 				Err(e) => {
-					write_err(e)?;
-					exit(1);
+					eprintln!("{}",e);
+					sh_quit(1);
 				}
 			}
-			exit(0);
 		} else {
 			match unsafe { fork()? } {
 				Child => {
@@ -177,26 +196,17 @@ fn exec_subshell(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 						exit(1);
 					}
 					for arg in argv {
-						shenv.vars_mut().bpush_arg(&arg.to_string());
+						let arg_raw = &arg.as_raw(shenv);
+						shenv.vars_mut().bpush_arg(arg_raw);
 					}
-					let body_raw = body.to_string();
-					let lexer_input = Rc::new(
-							body_raw[1..body_raw.len() - 1].to_string()
-					);
-					let token_stream = Lexer::new(lexer_input).lex();
-					match Parser::new(token_stream).parse() {
-						Ok(syn_tree) => {
-							if let Err(e) = Executor::new(syn_tree, shenv).walk() {
-								write_err(e)?;
-								exit(1);
-							}
-						}
+					let body_raw = body.as_raw(shenv);
+					match exec_input(body_raw, shenv) {
+						Ok(()) => sh_quit(0),
 						Err(e) => {
-							write_err(e)?;
-							exit(1);
+							eprintln!("{}",e);
+							sh_quit(1);
 						}
 					}
-					exit(0);
 				}
 				Parent { child } => {
 					*shenv = snapshot;
@@ -218,7 +228,7 @@ fn exec_subshell(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 fn exec_builtin(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 	log!(DEBUG, "Executing builtin");
 	let command = if let NdRule::Command { argv, redirs: _ } = node.rule() {
-		argv.first().unwrap().to_string()
+		argv.first().unwrap().as_raw(shenv)
 	} else { unreachable!() };
 
 	log!(TRACE, "{}", command.as_str());
@@ -232,6 +242,8 @@ fn exec_builtin(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 		"bg" => continue_job(node, shenv, false)?,
 		"read" => read_builtin(node, shenv)?,
 		"alias" => alias(node, shenv)?,
+		"exit" => sh_flow(node, shenv, ShErrKind::CleanExit)?,
+		"return" => sh_flow(node, shenv, ShErrKind::FuncReturn)?,
 		_ => unimplemented!("Have not yet implemented support for builtin `{}'",command)
 	}
 	log!(TRACE, "done");
@@ -247,7 +259,7 @@ fn exec_assignment(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 		let mut assigns = assignments.into_iter();
 		if let Some(cmd) = cmd {
 			while let Some(assign) = assigns.next() {
-				let assign_raw = assign.to_string();
+				let assign_raw = assign.as_raw(shenv);
 				if let Some((var,val)) = assign_raw.split_once('=') {
 					shenv.vars_mut().export(var, val);
 				}
@@ -259,7 +271,7 @@ fn exec_assignment(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 			}
 		} else {
 			while let Some(assign) = assigns.next() {
-				let assign_raw = assign.to_string();
+				let assign_raw = assign.as_raw(shenv);
 				if let Some((var,val)) = assign_raw.split_once('=') {
 					shenv.vars_mut().set_var(var, val);
 				}
@@ -288,7 +300,7 @@ fn exec_pipeline(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 				(Some(r_pipe),Some(w_pipe))
 			};
 			if let NdRule::Command { argv, redirs: _ } = cmd.rule() {
-				let cmd_name = argv.first().unwrap().span().get_slice().to_string();
+				let cmd_name = argv.first().unwrap().as_raw(shenv);
 				cmd_names.push(cmd_name);
 			} else if let NdRule::Subshell {..} = cmd.rule() {
 				cmd_names.push("subshell".to_string());
@@ -305,12 +317,12 @@ fn exec_pipeline(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 
 					// Create some redirections
 					if let Some(w_pipe) = w_pipe {
-						let wpipe_redir = Redir::new(1, RedirType::Output, RedirTarget::Fd(w_pipe.as_raw_fd()));
+						let wpipe_redir = Redir::output(1, w_pipe);
 						shenv.ctx_mut().push_rdr(wpipe_redir);
 					}
 					// Use the r_pipe created in the last iteration
 					if let Some(prev_rpipe) = prev_rpipe {
-						let rpipe_redir = Redir::new(0, RedirType::Input, RedirTarget::Fd(prev_rpipe.as_raw_fd()));
+						let rpipe_redir = Redir::input(0, prev_rpipe);
 						shenv.ctx_mut().push_rdr(rpipe_redir);
 					}
 
@@ -348,6 +360,7 @@ fn exec_pipeline(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 fn exec_cmd(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 	log!(DEBUG, "Executing command");
 	let blame = node.span();
+	let blame_raw = node.as_raw(shenv);
 	let rule = node.into_rule();
 
 	if let NdRule::Command { argv, redirs } = rule {
@@ -395,7 +408,7 @@ fn exec_cmd(node: Node, shenv: &mut ShEnv) -> ShResult<()> {
 				}
 			}
 		} else {
-			return Err(ShErr::full(ShErrKind::CmdNotFound, format!("{}", command), blame))
+			return Err(ShErr::full(ShErrKind::CmdNotFound, format!("{}", command), shenv.get_input(), blame))
 		}
 	} else { unreachable!("Found this rule in exec_cmd: {:?}", rule) }
 	Ok(())

src/expand/alias.rs

@@ -1,75 +1,62 @@
 use crate::{parse::lex::SEPARATORS, prelude::*};
 
-pub fn expand_aliases(input: &str, shenv: &mut ShEnv) -> Option<String> {
-	let mut result = input.to_string();
-	let mut expanded_aliases = Vec::new();
-	let mut found_in_iteration = true;
+pub fn expand_alias(candidate: Token, shenv: &mut ShEnv) -> Vec<Token> {
+	let mut tokens = vec![];
+	let mut work_stack = VecDeque::new();
+	let mut expanded_aliases = vec![];
+	let logic = shenv.logic().clone();
 
-	// Loop until no new alias expansion happens.
-	while found_in_iteration {
-		found_in_iteration = false;
-		let mut new_result = String::new();
-		let mut chars = result.chars().peekable();
-		let mut alias_cand = String::new();
-		let mut is_cmd = true;
+	// Start with the candidate token in the work queue
+	work_stack.bpush(candidate);
 
-		while let Some(ch) = chars.next() {
-			match ch {
-				';' | '\n' => {
-					new_result.push(ch);
-					is_cmd = true;
-					// Consume any extra whitespace or delimiters.
-					while let Some(&next_ch) = chars.peek() {
-						if matches!(next_ch, ' ' | '\t' | ';' | '\n') {
-							new_result.push(next_ch);
-							chars.next();
-						} else {
-							break;
-						}
+	// Process until there are no more tokens in the queue
+	while let Some(token) = work_stack.fpop() {
+		if token.rule() == TkRule::Ident {
+			let candidate_str = token.as_raw(shenv);
+			if let Some(alias) = logic.get_alias(&candidate_str) {
+				// Expand the alias only if it hasn't been expanded yet
+				if !expanded_aliases.contains(&candidate_str) {
+					expanded_aliases.push(candidate_str);
+					let mut new_tokens = shenv.expand_input(alias, token.span());
+					for token in new_tokens.iter_mut() {
+						work_stack.bpush(token.clone());
 					}
+				} else {
+					// If already expanded, just add the token to the output
+					tokens.push(token);
 				}
-				' ' | '\t' => {
-					is_cmd = false;
-					new_result.push(ch);
-				}
-				_ if is_cmd => {
-					// Accumulate token characters.
-					alias_cand.push(ch);
-					while let Some(&next_ch) = chars.peek() {
-						if matches!(next_ch, ' ' | '\t' | ';' | '\n') {
-							break;
-						} else {
-							alias_cand.push(next_ch);
-							chars.next();
-						}
-					}
-					// Check for an alias expansion.
-					if let Some(alias) = shenv.logic().get_alias(&alias_cand) {
-						// Only expand if we haven't already done so.
-						if !expanded_aliases.contains(&alias_cand) {
-							new_result.push_str(alias);
-							expanded_aliases.push(alias_cand.clone());
-							found_in_iteration = true;
-						} else {
-							new_result.push_str(&alias_cand);
-						}
-					} else {
-						new_result.push_str(&alias_cand);
-					}
-					alias_cand.clear();
-				}
-				_ => {
-					new_result.push(ch);
+			} else {
+				tokens.push(token);
+			}
+		} else {
+			tokens.push(token);
+		}
+	}
+	tokens
+}
+
+pub fn expand_aliases(tokens: Vec<Token>, shenv: &mut ShEnv) -> Vec<Token> {
+	let mut stream = tokens.iter();
+	let mut processed = vec![];
+	let mut is_command = true;
+	while let Some(token) = stream.next() {
+		match token.rule() {
+			_ if SEPARATORS.contains(&token.rule()) => {
+				is_command = true;
+				processed.push(token.clone());
+			}
+			TkRule::Ident if is_command => {
+				is_command = false;
+				let mut alias_tokens = expand_alias(token.clone(), shenv);
+				log!(DEBUG, alias_tokens);
+				if !alias_tokens.is_empty() {
+					processed.append(&mut alias_tokens);
+				} else {
+					processed.push(token.clone());
 				}
 			}
+			_ => processed.push(token.clone()),
 		}
-		result = new_result;
-		log!(DEBUG, result);
-	}
-
-	if expanded_aliases.is_empty() {
-		None
-	} else {
-		Some(result)
 	}
+	processed
 }

src/expand/cmdsub.rs

@@ -0,0 +1,30 @@
+use crate::prelude::*;
+
+pub fn expand_cmdsub(token: Token, shenv: &mut ShEnv) -> ShResult<Vec<Token>> {
+	let mut new_tokens = vec![];
+	let cmdsub_raw = token.as_raw(shenv);
+	let body = &cmdsub_raw[2..cmdsub_raw.len() - 1].to_string(); // From '$(this)' to 'this'
+
+	let (r_pipe,w_pipe) = c_pipe()?;
+	let pipe_redir = Redir::output(1, w_pipe);
+	let mut sub_shenv = shenv.clone();
+	sub_shenv.ctx_mut().set_flag(ExecFlags::NO_FORK);
+	sub_shenv.collect_redirs(vec![pipe_redir]);
+
+	match unsafe { fork()? } {
+		Child => {
+			close(r_pipe).ok();
+			exec_input(body, shenv).abort_if_err();
+			sh_quit(0);
+		}
+		Parent { child } => {
+			close(w_pipe).ok();
+		}
+	}
+	let output = read_to_string(r_pipe)?;
+	if !output.is_empty() {
+		let lex_input = Rc::new(output);
+	}
+
+	Ok(new_tokens)
+}

src/expand/mod.rs

@@ -1,9 +1,10 @@
-pub mod expand_vars;
+pub mod vars;
 pub mod tilde;
 pub mod alias;
+pub mod cmdsub;
 
 use alias::expand_aliases;
-use expand_vars::{expand_dquote, expand_var};
+use vars::{expand_dquote, expand_var};
 use tilde::expand_tilde;
 
 use crate::prelude::*;
@@ -11,7 +12,7 @@ use crate::prelude::*;
 pub fn expand_argv(argv: Vec<Token>, shenv: &mut ShEnv) -> Vec<Token> {
 	let mut processed = vec![];
 	for arg in argv {
-		log!(DEBUG, arg);
+		log!(DEBUG, "{}",arg.as_raw(shenv));
 		log!(DEBUG, processed);
 		match arg.rule() {
 			TkRule::DQuote => {
@@ -23,7 +24,7 @@ pub fn expand_argv(argv: Vec<Token>, shenv: &mut ShEnv) -> Vec<Token> {
 				processed.append(&mut varsub_exp);
 			}
 			TkRule::TildeSub => {
-				let tilde_exp = expand_tilde(arg.clone());
+				let tilde_exp = expand_tilde(arg.clone(), shenv);
 				processed.push(tilde_exp);
 			}
 			_ => {

src/expand/tilde.rs

@@ -1,12 +1,11 @@
 use crate::prelude::*;
 
-pub fn expand_tilde(tilde_sub: Token) -> Token {
-	let tilde_sub_raw = tilde_sub.to_string();
+pub fn expand_tilde(tilde_sub: Token, shenv: &mut ShEnv) -> Token {
+	let mut tilde_sub_raw = tilde_sub.as_raw(shenv);
 	if tilde_sub_raw.starts_with('~') {
 		let home = std::env::var("HOME").unwrap_or_default();
-		tilde_sub_raw.replacen('~', &home, 1);
-		let lex_input = Rc::new(tilde_sub_raw);
-		let mut tokens = Lexer::new(lex_input).lex();
+		tilde_sub_raw = tilde_sub_raw.replacen('~', &home, 1);
+		let mut tokens = Lexer::new(tilde_sub_raw,shenv).lex();
 		tokens.pop().unwrap_or(tilde_sub)
 	} else {
 		tilde_sub

src/expand/vars.rs

@@ -1,18 +1,15 @@
 use crate::{parse::lex::Token, prelude::*};
 
 pub fn expand_var(var_sub: Token, shenv: &mut ShEnv) -> Vec<Token> {
-	let var_name = var_sub.to_string();
+	let var_name = var_sub.as_raw(shenv);
 	let var_name = var_name.trim_start_matches('$').trim_matches(['{','}']);
-	let value = Rc::new(
-			shenv.vars()
-				.get_var(var_name)
-				.to_string()
-	);
-	Lexer::new(value).lex() // Automatically handles word splitting for us
+	let value = shenv.vars().get_var(var_name).to_string();
+
+	shenv.expand_input(&value, var_sub.span())
 }
 
 pub fn expand_dquote(dquote: Token, shenv: &mut ShEnv) -> Token {
-	let dquote_raw = dquote.to_string();
+	let dquote_raw = dquote.as_raw(shenv);
 	let mut result = String::new();
 	let mut var_name = String::new();
 	let mut chars = dquote_raw.chars().peekable();
@@ -63,5 +60,8 @@ pub fn expand_dquote(dquote: Token, shenv: &mut ShEnv) -> Token {
 
 	log!(DEBUG, result);
 
-	Lexer::new(Rc::new(result)).lex().pop().unwrap_or(dquote)
+	log!(DEBUG, "{:?}",dquote.span());
+	let token = shenv.expand_input(&result, dquote.span()).pop().unwrap_or(dquote);
+	log!(DEBUG, "{}",token.as_raw(shenv));
+	token
 }

src/libsh/error.rs

@@ -5,16 +5,62 @@ use crate::prelude::*;
 
 pub type ShResult<T> = Result<T,ShErr>;
 
+pub trait ResultExt {
+	fn eprint(self) -> Self;
+	fn abort_if_err(&self);
+}
+
+#[derive(Clone,Debug)]
+pub struct BlamePair {
+	input: String,
+	span: Rc<RefCell<Span>>
+}
+
+impl BlamePair {
+	pub fn new(input: String, span: Rc<RefCell<Span>>) -> Self {
+		Self { input, span }
+	}
+	pub fn start(&self) -> usize {
+		self.span.borrow().start()
+	}
+	pub fn end(&self) -> usize {
+		self.span.borrow().end()
+	}
+	pub fn len(&self) -> usize {
+		self.input.len()
+	}
+}
+
+impl Into<String> for BlamePair {
+	fn into(self) -> String {
+		self.input
+	}
+}
+
+impl<T, E: Display> ResultExt for Result<T, E> {
+	fn eprint(self) -> Self {
+		if let Err(err) = &self {
+			eprintln!("{}", err);
+		}
+		self
+	}
+	fn abort_if_err(&self) {
+		if let Err(err) = &self {
+			eprintln!("{}", err);
+			sh_quit(1)
+		}
+	}
+}
 
 pub trait Blame {
 	/// Blame a span for a propagated error. This will convert a ShErr::Simple into a ShErr::Full
 	/// This will also set the span on a ShErr::Builder
-	fn blame(self, span: Span) -> Self;
+	fn blame(self, input: String, span: Rc<RefCell<Span>>) -> Self;
 
 	/// If an error is propagated to this point, then attempt to blame a span.
 	/// If the error in question has already blamed a span, don't overwrite it.
 	/// Used as a last resort in higher level contexts in case an error somehow goes unblamed
-	fn try_blame(self, span: Span) -> Self;
+	fn try_blame(self, input: String, span: Rc<RefCell<Span>>) -> Self;
 }
 
 impl From<std::io::Error> for ShErr {
@@ -42,17 +88,17 @@ impl From<Errno> for ShErr {
 }
 
 impl<T> Blame for Result<T,ShErr> {
-	fn blame(self, span: Span) -> Self {
+	fn blame(self, input: String, span: Rc<RefCell<Span>>) -> Self {
 		if let Err(mut e) = self {
-			e.blame(span);
+			e.blame(input,span);
 			Err(e)
 		} else {
 			self
 		}
 	}
-	fn try_blame(self, span: Span) -> Self {
+	fn try_blame(self, input: String, span: Rc<RefCell<Span>>) -> Self {
 		if let Err(mut e) = self {
-			e.try_blame(span);
+			e.try_blame(input,span);
 			Err(e)
 		} else {
 			self
@@ -60,7 +106,7 @@ impl<T> Blame for Result<T,ShErr> {
 	}
 }
 
-#[derive(Debug,Clone)]
+#[derive(Debug,Copy,Clone,PartialEq,Eq)]
 pub enum ShErrKind {
 	IoErr,
 	SyntaxErr,
@@ -85,7 +131,7 @@ impl Default for ShErrKind {
 #[derive(Clone,Debug)]
 pub enum ShErr {
 	Simple { kind: ShErrKind, message: String },
-	Full { kind: ShErrKind, message: String, span: Span },
+	Full { kind: ShErrKind, message: String, blame: BlamePair },
 }
 
 impl ShErr {
@@ -95,32 +141,35 @@ impl ShErr {
 	pub fn io() -> Self {
 		io::Error::last_os_error().into()
 	}
-	pub fn full<S: Into<String>>(kind: ShErrKind, message: S, span: Span) -> Self {
-		Self::Full { kind, message: message.into(), span }
+	pub fn full<S: Into<String>>(kind: ShErrKind, message: S, input: String, span: Rc<RefCell<Span>>) -> Self {
+		let blame = BlamePair::new(input.to_string(), span);
+		Self::Full { kind, message: message.into(), blame }
 	}
-	pub fn try_blame(&mut self, blame: Span) {
+	pub fn try_blame(&mut self, input: String, span: Rc<RefCell<Span>>) {
+		let blame_pair = BlamePair::new(input, span);
 		match self {
 			Self::Full {..} => {
 				/* Do not overwrite */
 			}
 			Self::Simple { kind, message } => {
-				*self = Self::Full { kind: core::mem::take(kind), message: core::mem::take(message), span: blame }
+				*self = Self::Full { kind: core::mem::take(kind), message: core::mem::take(message), blame: blame_pair }
 			}
 		}
 	}
-	pub fn blame(&mut self, blame: Span) {
+	pub fn blame(&mut self, input: String, span: Rc<RefCell<Span>>) {
+		let blame_pair = BlamePair::new(input, span);
 		match self {
-			Self::Full { kind: _, message: _, span } => {
-				*span = blame;
+			Self::Full { kind: _, message: _, blame } => {
+				*blame = blame_pair;
 			}
 			Self::Simple { kind, message } => {
-				*self = Self::Full { kind: core::mem::take(kind), message: core::mem::take(message), span: blame }
+				*self = Self::Full { kind: core::mem::take(kind), message: core::mem::take(message), blame: blame_pair }
 			}
 		}
 	}
 	pub fn with_msg(&mut self, new_message: String) {
 		match self {
-			Self::Full { kind: _, message, span: _ } => {
+			Self::Full { kind: _, message, blame: _ } => {
 				*message = new_message
 			}
 			Self::Simple { kind: _, message } => {
@@ -128,9 +177,19 @@ impl ShErr {
 			}
 		}
 	}
+	pub fn kind(&self) -> ShErrKind {
+		match self {
+			ShErr::Simple { kind, message: _ } => {
+				*kind
+			}
+			ShErr::Full { kind, message: _, blame: _ } => {
+				*kind
+			}
+		}
+	}
 	pub fn with_kind(&mut self, new_kind: ShErrKind) {
 		match self {
-			Self::Full { kind, message: _, span: _ } => {
+			Self::Full { kind, message: _, blame: _ } => {
 				*kind = new_kind
 			}
 			Self::Simple { kind, message: _ } => {
@@ -141,7 +200,7 @@ impl ShErr {
 	pub fn display_kind(&self) -> String {
 		match self {
 			ShErr::Simple { kind, message: _ } |
-			ShErr::Full { kind, message: _, span: _ } => {
+			ShErr::Full { kind, message: _, blame: _ } => {
 				match kind {
 						ShErrKind::IoErr => "I/O Error: ".into(),
 						ShErrKind::SyntaxErr => "Syntax Error: ".into(),
@@ -159,9 +218,31 @@ impl ShErr {
 			}
 		}
 	}
+	pub fn get_line(&self) -> (usize,usize,String) {
+		if let ShErr::Full { kind, message, blame } = self {
+			unsafe {
+				let mut dist = 0;
+				let mut line_no = 0;
+				let window = self.get_window();
+				let mut lines = window.lines();
+				while let Some(line) = lines.next() {
+					line_no += 1;
+					dist += line.len();
+					if dist > blame.start() {
+						dist -= line.len();
+						let offset = blame.start() - dist;
+						return (offset,line_no,line.to_string())
+					}
+				}
+			}
+			(0,0,String::new())
+		} else {
+			(0,0,String::new())
+		}
+	}
 	pub fn get_window(&self) -> String {
-		if let ShErr::Full { kind: _, message: _, span } = self {
-			let window = span.get_slice();
+		if let ShErr::Full { kind: _, message: _, blame } = self.clone() {
+			let window: String = blame.into();
 			window.split_once('\n').unwrap_or((&window,"")).0.to_string()
 		} else {
 			String::new()
@@ -173,9 +254,10 @@ impl Display for ShErr {
 	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
 		let error_display = match self {
 			ShErr::Simple { kind: _, message } => format!("{}{}",self.display_kind(),message),
-			ShErr::Full { kind: _, message, span } => {
-				let (offset,line_no,line_text) = span.get_line();
-				let dist = span.end() - span.start();
+			ShErr::Full { kind: _, message, blame } => {
+				let (offset,line_no,line_text) = self.get_line();
+				log!(DEBUG, blame);
+				let dist = blame.len();
 				let padding = " ".repeat(offset);
 				let line_inner = "~".repeat(dist.saturating_sub(2));
 				let err_kind = &self.display_kind().styled(Style::Red | Style::Bold);

src/libsh/sys.rs

@@ -40,6 +40,31 @@ pub fn c_pipe() -> Result<(RawFd,RawFd),Errno> {
 	Ok((pipes[0],pipes[1]))
 }
 
+pub fn sh_quit(code: i32) -> ! {
+	write_jobs(|j| {
+		for job in j.jobs_mut().iter_mut().flatten() {
+			job.killpg(Signal::SIGTERM).ok();
+		}
+	});
+	exit(code);
+}
+
+pub fn read_to_string(fd: i32) -> ShResult<String> {
+	let mut buf = Vec::with_capacity(4096);
+	let mut temp_buf = [0u8;1024];
+
+	loop {
+		match read(fd, &mut temp_buf) {
+			Ok(0) => break, // EOF
+			Ok(n) => buf.extend_from_slice(&temp_buf[..n]),
+			Err(Errno::EINTR) => continue, // Retry on EINTR
+			Err(e) => return Err(e.into()), // Return other errors
+		}
+	}
+
+	Ok(String::from_utf8_lossy(&buf).to_string())
+}
+
 pub fn execvpe(cmd: String, argv: Vec<String>, envp: Vec<String>) -> Result<(),Errno> {
 	let cmd_raw = CString::new(cmd).unwrap();
 

src/libsh/utils.rs

@@ -3,10 +3,26 @@ use std::{os::fd::{AsFd, AsRawFd, BorrowedFd, FromRawFd, OwnedFd}, str::FromStr}
 
 use nix::libc::getpgrp;
 
-use crate::{expand::{expand_vars::{expand_dquote, expand_var}, tilde::expand_tilde}, prelude::*};
+use crate::prelude::*;
 
 use super::term::StyleSet;
 
+pub trait RedirTargetType {
+	fn as_tgt(self) -> RedirTarget;
+}
+
+impl RedirTargetType for PathBuf {
+	fn as_tgt(self) -> RedirTarget {
+		RedirTarget::File(self)
+	}
+}
+
+impl RedirTargetType for i32 {
+	fn as_tgt(self) -> RedirTarget {
+		RedirTarget::Fd(self)
+	}
+}
+
 pub trait StrOps {
 	/// This function operates on anything that implements `AsRef<str>` and `Display`, which is mainly strings.
 	/// It takes a 'Style' which can be passed as a single Style object like `Style::Cyan` or a Bit OR of many styles,
@@ -31,7 +47,7 @@ impl ArgVec for Vec<Token> {
 		let mut argv_iter = self.into_iter();
 		let mut argv_processed = vec![];
 		while let Some(arg) = argv_iter.next() {
-			let cleaned = trim_quotes(&arg);
+			let cleaned = trim_quotes(&arg.as_raw(shenv));
 			argv_processed.push(cleaned);
 		}
 		argv_processed
@@ -248,6 +264,12 @@ impl Redir {
 	pub fn new(src: i32, op: RedirType, tgt: RedirTarget) -> Self {
 		Self { src, op, tgt }
 	}
+	pub fn output(src: i32, tgt: impl RedirTargetType) -> Self {
+		Self::new(src, RedirType::Output, tgt.as_tgt())
+	}
+	pub fn input(src: i32, tgt: impl RedirTargetType) -> Self {
+		Self::new(src, RedirType::Input, tgt.as_tgt())
+	}
 }
 
 #[derive(Debug,Clone)]

src/main.rs

@@ -10,8 +10,6 @@ pub mod prompt;
 pub mod builtin;
 pub mod expand;
 
-use libc::PIPE_BUF;
-use nix::unistd::setpgid;
 use signal::sig_setup;
 
 use crate::prelude::*;
@@ -22,32 +20,13 @@ pub fn main() {
 
 	loop {
 		log!(TRACE, "Entered loop");
-		let mut line = match prompt::read_line(&mut shenv) {
+		let line = match prompt::read_line(&mut shenv) {
 			Ok(line) => line,
 			Err(e) => {
 				eprintln!("{}",e);
 				continue;
 			}
 		};
-		if let Some(line_exp) = expand_aliases(&line, &mut shenv) {
-			line = line_exp;
-		}
-		let input = Rc::new(line);
-		log!(INFO, "New input: {:?}", input);
-		let token_stream = Lexer::new(input).lex();
-		log!(DEBUG, token_stream);
-		log!(DEBUG, token_stream);
-		log!(TRACE, "Token stream: {:?}", token_stream);
-		match Parser::new(token_stream).parse() {
-			Err(e) => {
-				eprintln!("{}",e);
-			}
-			Ok(syn_tree) => {
-				if let Err(e) = Executor::new(syn_tree, &mut shenv).walk() {
-					eprintln!("{}",e);
-				}
-			}
-		}
-		log!(TRACE, "Finished iteration");
+		let _ = exec_input(line, &mut shenv).eprint();
 	}
 }

src/parse/lex.rs

@@ -1,66 +1,66 @@
-use std::fmt::{Debug, Display};
+use std::{cell::Ref, fmt::{Debug, Display}};
 
 use crate::prelude::*;
 
-pub const KEYWORDS: [&str;14] = [
-	"if",
-	"then",
-	"elif",
-	"else",
-	"fi",
-	"while",
-	"until",
-	"for",
-	"in",
-	"select",
-	"do",
-	"done",
-	"case",
-	"esac"
+pub const KEYWORDS: [TkRule;14] = [
+	TkRule::If,
+	TkRule::Then,
+	TkRule::Elif,
+	TkRule::Else,
+	TkRule::Fi,
+	TkRule::While,
+	TkRule::Until,
+	TkRule::For,
+	TkRule::In,
+	TkRule::Select,
+	TkRule::Do,
+	TkRule::Done,
+	TkRule::Case,
+	TkRule::Esac
 ];
 
-pub const SEPARATORS: [TkRule; 7] = [
+pub const SEPARATORS: [TkRule; 6] = [
 	TkRule::Sep,
 	TkRule::AndOp,
 	TkRule::OrOp,
 	TkRule::PipeOp,
 	TkRule::ErrPipeOp,
 	TkRule::BgOp,
-	TkRule::Keyword // Keywords don't count as command names
 ];
 
 pub trait LexRule {
 	fn try_match(input: &str) -> Option<usize>;
 }
 
-pub struct Lexer {
-	input: Rc<String>,
+pub struct Lexer<'a> {
+	input: String,
 	tokens: Vec<Token>,
 	is_command: bool,
+	shenv: &'a mut ShEnv,
 	consumed: usize
 }
 
-impl Lexer {
-	pub fn new(input: Rc<String>) -> Self {
-		Self { input, tokens: vec![], is_command: true, consumed: 0  }
+impl<'a> Lexer<'a> {
+	pub fn new(input: String, shenv: &'a mut ShEnv) -> Self {
+		Self { input, tokens: vec![], is_command: true, shenv, consumed: 0  }
 	}
 	pub fn lex(mut self) -> Vec<Token> {
 		unsafe {
 			let mut input = self.input.as_str();
 			while let Some((mut rule,len)) = TkRule::try_match(input) {
 				// If we see a keyword in an argument position, it's actually an ident
-				if !self.is_command && rule == TkRule::Keyword {
+				if !self.is_command && KEYWORDS.contains(&rule) {
 					rule = TkRule::Ident
 
 				// If we are in a command right now, after this we are in arguments
-				} else if self.is_command && !matches!(rule,TkRule::Keyword | TkRule::Whitespace) {
+				} else if self.is_command && rule != TkRule::Whitespace && !KEYWORDS.contains(&rule) {
 					self.is_command = false;
 				}
 				// If we see a separator like && or ;, we are now in a command again
 				if SEPARATORS.contains(&rule) {
 					self.is_command = true;
 				}
-				let span = Span::new(self.input.clone(),self.consumed,self.consumed + len);
+				let span = self.shenv.inputman_mut().new_span(self.consumed, self.consumed + len);
 				let token = Token::new(rule, span);
 				self.consumed += len;
 				input = &input[len..];
@@ -77,73 +77,43 @@ impl Lexer {
 #[derive(Clone)]
 pub struct Token {
 	rule: TkRule,
-	span: Span
+	span: Rc<RefCell<Span>>
 }
 
 impl Token {
-	pub fn new(rule: TkRule, span: Span) -> Self {
+	pub fn new(rule: TkRule, span: Rc<RefCell<Span>>) -> Self {
 		Self { rule, span }
 	}
 
-	pub fn span(&self) -> &Span {
-		&self.span
-	}
-
-	pub fn span_mut(&mut self) -> &mut Span {
-		&mut self.span
+	pub fn span(&self) -> Rc<RefCell<Span>> {
+		self.span.clone()
 	}
 
 	pub fn rule(&self) -> TkRule {
 		self.rule
 	}
+
+	pub fn as_raw(&self, shenv: &mut ShEnv) -> String {
+		shenv.input_slice(self.span()).to_string()
+	}
 }
 
 impl Debug for Token {
 	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-		let info = (self.rule(),self.to_string(),self.span.start,self.span.end);
+		let info = (self.rule(),self.span.borrow().start,self.span.borrow().end);
 		write!(f,"{:?}",info)
 	}
 }
 
-impl Display for Token {
-	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-		let slice = self.span.get_slice();
-		write!(f,"{}",slice)
-	}
-}
-
 #[derive(Debug,Clone)]
 pub struct Span {
-	input: Rc<String>,
 	start: usize,
 	end: usize
 }
 
 impl Span {
-	pub fn new(input: Rc<String>, start: usize, end: usize) -> Self {
-		Self { input, start, end } }
-	pub fn get_slice(&self) -> String {
-		unsafe {
-			let slice = &self.input[self.start..self.end];
-			slice.to_string()
-		}
-	}
-	pub fn get_line(&self) -> (usize,usize,String) {
-		unsafe {
-			let mut dist = 0;
-			let mut line_no = 0;
-			let mut lines = self.input.lines();
-			while let Some(line) = lines.next() {
-				line_no += 1;
-				dist += line.len();
-				if dist > self.start {
-					dist -= line.len();
-					let offset = self.start - dist;
-					return (offset,line_no,line.to_string())
-				}
-			}
-		}
-		(0,0,String::new())
+	pub fn new(start: usize, end: usize) -> Self {
+		Self { start, end }
 	}
 	pub fn start(&self) -> usize {
 		self.start
@@ -151,8 +121,19 @@ impl Span {
 	pub fn end(&self) -> usize {
 		self.end
 	}
-	pub fn get_input(&self) -> Rc<String> {
-		self.input.clone()
+	pub fn clamp_start(&mut self, start: usize) {
+		if self.start > start {
+			self.start = start
+		}
+	}
+	pub fn clamp_end(&mut self, end: usize) {
+		if self.end > end {
+			self.end = end
+		}
+	}
+	pub fn shift(&mut self, delta: isize) {
+		self.start = self.start.saturating_add_signed(delta);
+		self.end = self.end.saturating_add_signed(delta);
 	}
 }
 
@@ -204,7 +185,20 @@ pub enum TkRule {
 	CmdSub,
 	DQuote,
 	SQuote,
-	Keyword,
+	If,
+	Then,
+	Elif,
+	Else,
+	Fi,
+	While,
+	Until,
+	For,
+	In,
+	Select,
+	Do,
+	Done,
+	Case,
+	Esac,
 	Assign,
 	Ident,
 	Sep,
@@ -232,8 +226,21 @@ impl TkRule {
 		try_match!(TildeSub,input);
 		try_match!(Subshell,input);
 		try_match!(Sep,input);
-		try_match!(Keyword,input);
 		try_match!(Assign,input);
+		try_match!(If,input);
+		try_match!(Then,input);
+		try_match!(Elif,input);
+		try_match!(Else,input);
+		try_match!(Fi,input);
+		try_match!(While,input);
+		try_match!(Until,input);
+		try_match!(For,input);
+		try_match!(In,input);
+		try_match!(Select,input);
+		try_match!(Do,input);
+		try_match!(Done,input);
+		try_match!(Case,input);
+		try_match!(Esac,input);
 		try_match!(Ident,input);
 		None
 	}
@@ -371,17 +378,159 @@ tkrule_def!(OrOp, |input: &str| {
 	}
 });
 
-
-tkrule_def!(Keyword, |input: &str| {
-	for &kw in KEYWORDS.iter() {
-		if input.starts_with(kw) {
-			let len = kw.len();
-			if input.chars().nth(len).map_or(true, |ch| ch.is_whitespace() || ch == ';') {
-				return Some(len);
-			}
+tkrule_def!(If, |input: &str| {
+	if input.starts_with("if") {
+		match input.chars().nth(2) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(2),
+			Some(_) => None,
+			None => Some(2), // "if" is the entire input
 		}
+	} else {
+		None
+	}
+});
+tkrule_def!(Then, |input: &str| {
+	if input.starts_with("then") {
+		match input.chars().nth(4) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(4),
+			Some(_) => None,
+			None => Some(4), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(Elif, |input: &str| {
+	if input.starts_with("elif") {
+		match input.chars().nth(4) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(4),
+			Some(_) => None,
+			None => Some(4), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(Else, |input: &str| {
+	if input.starts_with("else") {
+		match input.chars().nth(4) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(4),
+			Some(_) => None,
+			None => Some(4), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(Fi, |input: &str| {
+	if input.starts_with("fi") {
+		match input.chars().nth(2) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(2),
+			Some(_) => None,
+			None => Some(2), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(While, |input: &str| {
+	if input.starts_with("while") {
+		match input.chars().nth(5) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(5),
+			Some(_) => None,
+			None => Some(5), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(Until, |input: &str| {
+	if input.starts_with("until") {
+		match input.chars().nth(5) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(5),
+			Some(_) => None,
+			None => Some(5), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(For, |input: &str| {
+	if input.starts_with("for") {
+		match input.chars().nth(3) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(3),
+			Some(_) => None,
+			None => Some(3), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(In, |input: &str| {
+	if input.starts_with("in") {
+		match input.chars().nth(2) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(2),
+			Some(_) => None,
+			None => Some(2), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(Select, |input: &str| {
+	if input.starts_with("select") {
+		match input.chars().nth(6) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(6),
+			Some(_) => None,
+			None => Some(6), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(Do, |input: &str| {
+	if input.starts_with("do") {
+		match input.chars().nth(2) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(2),
+			Some(_) => None,
+			None => Some(2), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(Done, |input: &str| {
+	if input.starts_with("done") {
+		match input.chars().nth(4) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(4),
+			Some(_) => None,
+			None => Some(4), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(Case, |input: &str| {
+	if input.starts_with("case") {
+		match input.chars().nth(4) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(4),
+			Some(_) => None,
+			None => Some(4), // "if" is the entire input
+		}
+	} else {
+		None
+	}
+});
+tkrule_def!(Esac, |input: &str| {
+	if input.starts_with("esac") {
+		match input.chars().nth(4) {
+			Some(ch) if ch.is_whitespace() || ch == ';' => Some(4),
+			Some(_) => None,
+			None => Some(4), // "if" is the entire input
+		}
+	} else {
+		None
 	}
-	None
 });
 
 tkrule_def!(Ident, |input: &str| {
@@ -717,6 +866,14 @@ tkrule_def!(BraceGrp, |input: &str| {
 });
 
 tkrule_def!(RedirOp, |input: &str| {
+	if let Some(ch) = input.chars().next() {
+		match ch {
+			'>' |
+			'<' |
+			'&' => { /* Continue */ }
+			_ => return None
+		}
+	}
 	// Order matters here
 	// For instance, if '>' is checked before '>>', '>' will always match first, and '>>' will never be checked
 	try_match_inner!(RedirCombineAppend,input); // Ex: &>>

src/parse/parse.rs

@@ -1,9 +1,9 @@
 use core::fmt::Display;
-use std::str::FromStr;
+use std::{cell::Ref, str::FromStr};
 
 use crate::prelude::*;
 
-use super::lex::{TkRule, Span, Token};
+use super::lex::{Span, TkRule, Token, KEYWORDS};
 
 bitflags! {
 	#[derive(Debug,Clone,Copy,PartialEq,Eq)]
@@ -17,12 +17,12 @@ bitflags! {
 
 pub trait ParseRule {
 	/// Used for cases where a rule is optional
-	fn try_match(input: &[Token]) -> ShResult<Option<Node>>;
+	fn try_match(input: &[Token], shenv: &mut ShEnv) -> ShResult<Option<Node>>;
 	/// Used for cases where a rule is assumed based on context
 	/// For instance, if the "for" keyword is encountered, then it *must* be a for loop
 	/// And if it isn't, return a parse error
-	fn assert_match(input: &[Token]) -> ShResult<Node> {
-		Self::try_match(input)?.ok_or_else(||
+	fn assert_match(input: &[Token], shenv: &mut ShEnv) -> ShResult<Node> {
+		Self::try_match(input,shenv)?.ok_or_else(||
 			ShErr::simple(ShErrKind::ParseErr, "Parse Error")
 		)
 	}
@@ -40,7 +40,7 @@ pub enum CmdGuard {
 pub struct Node {
 	node_rule: NdRule,
 	tokens: Vec<Token>,
-	span: Span,
+	span: Rc<RefCell<Span>>,
 	flags: NdFlag,
 }
 
@@ -60,9 +60,12 @@ impl Node {
 	pub fn into_rule(self) -> NdRule {
 		self.node_rule
 	}
-	pub fn span(&self) -> Span {
+	pub fn span(&self) -> Rc<RefCell<Span>> {
 		self.span.clone()
 	}
+	pub fn as_raw(&self, shenv: &mut ShEnv) -> String {
+		shenv.input_slice(self.span()).to_string()
+	}
 	pub fn flags(&self) -> NdFlag {
 		self.flags
 	}
@@ -71,11 +74,10 @@ impl Node {
 	}
 }
 
-impl Display for Node {
-	fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-		let raw = self.span().get_slice();
-		write!(f, "{}", raw)
-	}
+#[derive(Clone,Debug)]
+pub enum LoopKind {
+	While,
+	Until
 }
 
 #[derive(Clone,Debug)]
@@ -84,6 +86,9 @@ pub enum NdRule {
 	Command { argv: Vec<Token>, redirs: Vec<Redir> },
 	Assignment { assignments: Vec<Token>, cmd: Option<Box<Node>> },
 	FuncDef { name: Token, body: Token },
+	IfThen { cond_blocks: Vec<(Vec<Node>,Vec<Node>)>, else_block: Option<Vec<Node>> },
+	Loop { kind: LoopKind, cond: Vec<Node>, body: Vec<Node> },
+	ForLoop { vars: Vec<Token>, arr: Vec<Token>, body: Vec<Node> },
 	Subshell { body: Token, argv: Vec<Token>, redirs: Vec<Redir> },
 	CmdList { cmds: Vec<(Option<CmdGuard>,Node)> },
 	Pipeline { cmds: Vec<Node> }
@@ -91,12 +96,12 @@ pub enum NdRule {
 
 /// Define a Node rule. The body of this macro becomes the implementation for the try_match() method for the rule.
 macro_rules! ndrule_def {
-	($name:ident,$try:expr) => {
+	($name:ident,$shenv:ident,$try:expr) => {
 		#[derive(Debug)]
 		pub struct $name;
 		impl ParseRule for $name {
-			fn try_match(input: &[Token]) -> ShResult<Option<Node>> {
-				$try(input)
+			fn try_match(input: &[Token],shenv: &mut ShEnv) -> ShResult<Option<Node>> {
+				$try(input,shenv)
 			}
 		}
 	};
@@ -105,9 +110,9 @@ macro_rules! ndrule_def {
 /// This macro attempts to match all of the given Rules. It returns upon finding the first match, so the order matters
 /// Place the most specialized/specific rules first, and the most general rules last
 macro_rules! try_rules {
-    ($tokens:expr, $($name:ident),+) => {
+    ($tokens:expr,$shenv:expr,$($name:ident),+) => {
 			$(
-				let result = $name::try_match($tokens)?;
+				let result = $name::try_match($tokens,$shenv)?;
 				if let Some(node) = result {
 					return Ok(Some(node))
 				}
@@ -125,6 +130,9 @@ impl SynTree {
 	pub fn new() -> Self {
 		Self { tree: VecDeque::new() }
 	}
+	pub fn from_vec(nodes: Vec<Node>) -> Self {
+		Self { tree: VecDeque::from(nodes) }
+	}
 	pub fn push_node(&mut self, node: Node) {
 		self.tree.bpush(node)
 	}
@@ -133,16 +141,17 @@ impl SynTree {
 	}
 }
 
-pub struct Parser {
+pub struct Parser<'a> {
 	token_stream: Vec<Token>,
+	shenv: &'a mut ShEnv,
 	ast: SynTree
 }
 
-impl Parser {
-	pub fn new(mut token_stream: Vec<Token>) -> Self {
+impl<'a> Parser<'a> {
+	pub fn new(mut token_stream: Vec<Token>, shenv: &'a mut ShEnv) -> Self {
 		log!(TRACE, "New parser");
 		token_stream.retain(|tk| !matches!(tk.rule(), TkRule::Whitespace | TkRule::Comment));
-		Self { token_stream, ast: SynTree::new() }
+		Self { token_stream, shenv, ast: SynTree::new() }
 	}
 
 	pub fn parse(mut self) -> ShResult<SynTree> {
@@ -150,11 +159,10 @@ impl Parser {
 		let mut lists = VecDeque::new();
 		let token_slice = &*self.token_stream;
 		// Get the Main rule
-		if let Some(mut node) = Main::try_match(token_slice)? {
+		if let Some(mut node) = Main::try_match(token_slice,self.shenv)? {
 			// Extract the inner lists
 			if let NdRule::Main { ref mut cmd_lists } = node.rule_mut() {
 				while let Some(node) = cmd_lists.pop() {
-					log!(DEBUG, node);
 					lists.bpush(node)
 				}
 			}
@@ -167,26 +175,42 @@ impl Parser {
 	}
 }
 
-fn get_span(toks: &Vec<Token>) -> ShResult<Span> {
+fn get_span(toks: &Vec<Token>, shenv: &mut ShEnv) -> ShResult<Rc<RefCell<Span>>> {
 	if toks.is_empty() {
 		Err(ShErr::simple(ShErrKind::InternalErr, "Get_span was given an empty token list"))
 	} else {
-		let start = toks.first().unwrap().span().start();
-		let end = toks.iter().last().unwrap().span().end();
-		let input = toks.iter().last().unwrap().span().get_input();
-		Ok(Span::new(input,start,end))
+		let start = toks.first().unwrap().span().borrow().start();
+		let end = toks.iter().last().unwrap().span().borrow().end();
+		let span = shenv.inputman_mut().new_span(start, end);
+		Ok(span)
 	}
 }
 
+fn get_lists(mut tokens: &[Token], shenv: &mut ShEnv) -> (usize,Vec<Node>) {
+	let mut lists = vec![];
+	let mut tokens_eaten = 0;
+	while !tokens.is_empty() {
+		match CmdList::try_match(tokens, shenv) {
+			Ok(Some(list)) => {
+				tokens_eaten += list.len();
+				tokens = &tokens[list.len()..];
+				lists.push(list);
+			}
+			Ok(None) | Err(_) => break
+		}
+	}
+	(tokens_eaten,lists)
+}
+
 // TODO: Redirs with FD sources appear to be looping endlessly for some reason
 
-ndrule_def!(Main, |tokens: &[Token]| {
+ndrule_def!(Main, shenv, |tokens: &[Token], shenv: &mut ShEnv| {
 	log!(TRACE, "Parsing main");
 	let mut cmd_lists = vec![];
 	let mut node_toks = vec![];
 	let mut token_slice = &*tokens;
 
-	while let Some(node) = CmdList::try_match(token_slice)? {
+	while let Some(node) = CmdList::try_match(token_slice,shenv)? {
 		node_toks.extend(node.tokens().clone());
 		token_slice = &token_slice[node.len()..];
 		cmd_lists.push(node);
@@ -195,7 +219,7 @@ ndrule_def!(Main, |tokens: &[Token]| {
 	if cmd_lists.is_empty() {
 		return Ok(None)
 	}
-	let span = get_span(&node_toks)?;
+	let span = get_span(&node_toks,shenv)?;
 	let node = Node {
 		node_rule: NdRule::Main { cmd_lists },
 		tokens: node_toks,
@@ -205,14 +229,14 @@ ndrule_def!(Main, |tokens: &[Token]| {
 	Ok(Some(node))
 });
 
-ndrule_def!(CmdList, |tokens: &[Token]| {
+ndrule_def!(CmdList, shenv, |tokens: &[Token], shenv: &mut ShEnv| {
 	log!(TRACE, "Parsing cmdlist");
 	let mut commands: Vec<(Option<CmdGuard>,Node)> = vec![];
 	let mut node_toks = vec![];
 	let mut token_slice = &*tokens;
 	let mut cmd_guard = None; // Operators like '&&' and '||'
 
-	while let Some(mut node) = Expr::try_match(token_slice)? {
+	while let Some(mut node) = Expr::try_match(token_slice,shenv)? {
 		// Add sub-node tokens to our tokens
 		node_toks.extend(node.tokens().clone());
 		// Reflect changes in the token slice
@@ -221,8 +245,11 @@ ndrule_def!(CmdList, |tokens: &[Token]| {
 		log!(DEBUG, token_slice);
 		// Push sub-node
 		if let NdRule::Command { argv, redirs: _ } = node.rule() {
-			if argv.first().is_some_and(|arg| BUILTINS.contains(&arg.to_string().as_str())) {
-				*node.flags_mut() |= NdFlag::BUILTIN;
+			if let Some(arg) = argv.first() {
+				let slice = shenv.input_slice(arg.span().clone());
+				if BUILTINS.contains(&slice) {
+					*node.flags_mut() |= NdFlag::BUILTIN;
+				}
 			}
 		}
 		commands.push((cmd_guard.take(),node));
@@ -244,7 +271,7 @@ ndrule_def!(CmdList, |tokens: &[Token]| {
 	if node_toks.is_empty() {
 		return Ok(None)
 	}
-	let span = get_span(&node_toks)?;
+	let span = get_span(&node_toks,shenv)?;
 	let node = Node {
 		node_rule: NdRule::CmdList { cmds: commands },
 		tokens: node_toks,
@@ -254,8 +281,8 @@ ndrule_def!(CmdList, |tokens: &[Token]| {
 	Ok(Some(node))
 });
 
-ndrule_def!(Expr, |tokens: &[Token]| {
-	try_rules!(tokens,
+ndrule_def!(Expr, shenv, |tokens: &[Token], shenv: &mut ShEnv| {
+	try_rules!(tokens, shenv,
 		ShellCmd,
 		Pipeline,
 		Subshell,
@@ -264,8 +291,8 @@ ndrule_def!(Expr, |tokens: &[Token]| {
 	);
 });
 // Used in pipelines to avoid recursion
-ndrule_def!(ExprNoPipeline, |tokens: &[Token]| {
-	try_rules!(tokens,
+ndrule_def!(ExprNoPipeline, shenv, |tokens: &[Token], shenv: &mut ShEnv| {
+	try_rules!(tokens, shenv,
 		ShellCmd,
 		Subshell,
 		Assignment,
@@ -273,13 +300,352 @@ ndrule_def!(ExprNoPipeline, |tokens: &[Token]| {
 	);
 });
 
-ndrule_def!(ShellCmd, |tokens: &[Token]| {
-	try_rules!(tokens,
+ndrule_def!(ShellCmd, shenv, |tokens: &[Token], shenv: &mut ShEnv| {
+	try_rules!(tokens, shenv,
+		IfThen,
+		Loop,
 		FuncDef
 	);
 });
 
-ndrule_def!(FuncDef, |tokens: &[Token]| {
+ndrule_def!(ForLoop, shenv, |mut tokens: &[Token], shenv: &mut ShEnv| {
+	let err = |msg: &str, span: Rc<RefCell<Span>>, shenv: &mut ShEnv | {
+		ShErr::full(ShErrKind::ParseErr, msg, shenv.get_input(), span)
+	};
+	let mut tokens_iter = tokens.iter().peekable();
+	let mut node_toks = vec![];
+	let mut vars = vec![];
+	let mut arr = vec![];
+	let body: Vec<Node>;
+
+	if let Some(token) = tokens_iter.next() {
+		if let TkRule::For = token.rule() {
+			node_toks.push(token.clone());
+			tokens = &tokens[1..];
+		} else { return Ok(None) }
+	} else { return Ok(None) }
+
+	while let Some(token) = tokens_iter.next() {
+		if let TkRule::Ident = token.rule() {
+			node_toks.push(token.clone());
+			tokens = &tokens[1..];
+			if token.as_raw(shenv) == "in" { break }
+			vars.push(token.clone());
+		} else {
+			let span = get_span(&node_toks, shenv)?;
+			return Err(err("Expected an ident in for loop vars",span,shenv))
+		}
+	}
+	if vars.is_empty() {
+		let span = get_span(&node_toks, shenv)?;
+		return Err(err("Expected an ident in for loop vars",span,shenv))
+	}
+	while let Some(token) = tokens_iter.next() {
+		if let TkRule::Ident = token.rule() {
+			node_toks.push(token.clone());
+			tokens = &tokens[1..];
+			if token.rule() == TkRule::Sep { break }
+			arr.push(token.clone());
+		} else {
+			let span = get_span(&node_toks, shenv)?;
+			return Err(err("Expected an ident in for loop array",span,shenv))
+		}
+	}
+	if arr.is_empty() {
+		let span = get_span(&node_toks, shenv)?;
+		return Err(err("Expected an ident in for loop array",span,shenv))
+	}
+
+	if let Some(token) = tokens_iter.next() {
+		node_toks.push(token.clone());
+		tokens = &tokens[1..];
+		if token.rule() != TkRule::Do {
+			let span = get_span(&node_toks, shenv)?;
+			return Err(err("Expected `do` after for loop array",span,shenv))
+		}
+	} else {
+		let span = get_span(&node_toks, shenv)?;
+		return Err(err("Expected `do` after for loop array",span,shenv))
+	}
+
+	let (used,lists) = get_lists(tokens, shenv);
+	for list in &lists {
+		node_toks.extend(list.tokens().clone());
+	}
+	tokens = &tokens[used..];
+	body = lists;
+	tokens_iter = tokens.iter().peekable();
+
+	if let Some(token) = tokens_iter.next() {
+		node_toks.push(token.clone());
+		if token.rule() != TkRule::Done {
+			let span = get_span(&node_toks, shenv)?;
+			return Err(err("Expected `done` after for loop",span,shenv))
+		}
+	} else {
+		let span = get_span(&node_toks, shenv)?;
+		return Err(err("Expected `done` after for loop",span,shenv))
+	}
+
+	let span = get_span(&node_toks, shenv)?;
+	let node = Node {
+		node_rule: NdRule::ForLoop { vars, arr, body },
+		tokens: node_toks,
+		span,
+		flags: NdFlag::empty()
+	};
+
+	Ok(Some(node))
+});
+
+ndrule_def!(IfThen, shenv, |mut tokens: &[Token], shenv: &mut ShEnv| {
+	let err = |msg: &str, span: Rc<RefCell<Span>>, shenv: &mut ShEnv | {
+		ShErr::full(ShErrKind::ParseErr, msg, shenv.get_input(), span)
+	};
+	let mut tokens_iter = tokens.iter().peekable();
+	let mut node_toks = vec![];
+	let mut cond_blocks = vec![];
+	let mut else_block: Option<Vec<Node>> = None;
+
+	if let Some(token) = tokens_iter.next() {
+		if let TkRule::If = token.rule() {
+			node_toks.push(token.clone());
+			tokens = &tokens[1..];
+		} else { return Ok(None) }
+	} else { return Ok(None) }
+
+	let (used,lists) = get_lists(tokens, shenv);
+	for list in &lists {
+		node_toks.extend(list.tokens().clone());
+	}
+	tokens = &tokens[used..];
+	let cond = lists;
+	tokens_iter = tokens.iter().peekable();
+
+	while let Some(token) = tokens_iter.next() {
+		match token.rule() {
+			TkRule::Then => {
+				node_toks.push(token.clone());
+				tokens = &tokens[1..];
+				break
+			}
+			TkRule::Sep | TkRule::Whitespace => {
+				node_toks.push(token.clone());
+				tokens = &tokens[1..];
+			}
+			_ => {
+				let span = get_span(&node_toks,shenv)?;
+				return Err(err("Expected `then` after if statement condition",span,shenv))
+			}
+		}
+	}
+
+	if tokens_iter.peek().is_none() {
+		let span = get_span(&node_toks,shenv)?;
+		return Err(err("Failed to parse this if statement",span,shenv))
+	}
+
+	let (used,lists) = get_lists(tokens, shenv);
+	for list in &lists {
+		node_toks.extend(list.tokens().clone());
+	}
+	tokens = &tokens[used..];
+	let body = lists;
+	tokens_iter = tokens.iter().peekable();
+	cond_blocks.push((cond,body));
+
+
+	let mut closed = false;
+	while let Some(token) = tokens_iter.next() {
+		match token.rule() {
+			TkRule::Elif => {
+				node_toks.push(token.clone());
+				tokens = &tokens[1..];
+
+				let (used,lists) = get_lists(tokens, shenv);
+				for list in &lists {
+					node_toks.extend(list.tokens().clone());
+				}
+				tokens = &tokens[used..];
+				let cond = lists;
+				tokens_iter = tokens.iter().peekable();
+
+				while let Some(token) = tokens_iter.next() {
+					match token.rule() {
+						TkRule::Then => {
+							node_toks.push(token.clone());
+							tokens = &tokens[1..];
+							break
+						}
+						TkRule::Sep | TkRule::Whitespace => {
+							node_toks.push(token.clone());
+							tokens = &tokens[1..];
+						}
+						_ => {
+							let span = get_span(&node_toks,shenv)?;
+							return Err(err("Expected `then` after if statement condition",span,shenv))
+						}
+					}
+				}
+
+				if tokens_iter.peek().is_none() {
+					let span = get_span(&node_toks,shenv)?;
+					return Err(err("Failed to parse this if statement",span,shenv))
+				}
+
+				let (used,lists) = get_lists(tokens, shenv);
+				for list in &lists {
+					node_toks.extend(list.tokens().clone());
+				}
+				tokens = &tokens[used..];
+				let body = lists;
+				tokens_iter = tokens.iter().peekable();
+				cond_blocks.push((cond,body));
+			}
+			TkRule::Else => {
+				node_toks.push(token.clone());
+				tokens = &tokens[1..];
+				let (used,lists) = get_lists(tokens, shenv);
+				for list in &lists {
+					node_toks.extend(list.tokens().clone());
+				}
+				tokens = &tokens[used..];
+				else_block = Some(lists);
+				tokens_iter = tokens.iter().peekable();
+			}
+			TkRule::Fi => {
+				closed = true;
+				node_toks.push(token.clone());
+				tokens = &tokens[1..];
+			}
+			TkRule::Sep | TkRule::Whitespace => {
+				node_toks.push(token.clone());
+				tokens = &tokens[1..];
+				if closed { break }
+			}
+			_ => {
+				let span = get_span(&node_toks, shenv)?;
+				return Err(err("Unexpected token in if statement",span,shenv))
+			}
+		}
+	}
+
+	if !closed {
+		let span = get_span(&node_toks, shenv)?;
+		return Err(err("Expected `fi` to close if statement",span,shenv))
+	}
+
+	let span = get_span(&node_toks, shenv)?;
+	let node = Node {
+		node_rule: NdRule::IfThen { cond_blocks, else_block },
+		tokens: node_toks,
+		span,
+		flags: NdFlag::empty()
+	};
+
+	Ok(Some(node))
+});
+
+ndrule_def!(Loop, shenv, |mut tokens: &[Token], shenv: &mut ShEnv| {
+	let err = |msg: &str, span: Rc<RefCell<Span>>, shenv: &mut ShEnv | {
+		ShErr::full(ShErrKind::ParseErr, msg, shenv.get_input(), span)
+	};
+	let mut tokens_iter = tokens.iter().peekable();
+	let mut node_toks = vec![];
+	let kind: LoopKind;
+	let cond: Vec<Node>;
+	let body: Vec<Node>;
+
+	if let Some(token) = tokens_iter.next() {
+		node_toks.push(token.clone());
+		match token.rule() {
+			TkRule::While => {
+				kind = LoopKind::While
+			}
+			TkRule::Until => {
+				kind = LoopKind::Until
+			}
+			_ => return Ok(None)
+		}
+	} else { return Ok(None) }
+	tokens = &tokens[1..];
+
+	let (used,lists) = get_lists(tokens, shenv);
+	for list in &lists {
+		node_toks.extend(list.tokens().clone());
+	}
+	tokens = &tokens[used..];
+	cond = lists;
+	tokens_iter = tokens.iter().peekable();
+
+	while let Some(token) = tokens_iter.next() {
+		match token.rule() {
+			TkRule::Sep | TkRule::Whitespace => {
+				node_toks.push(token.clone());
+				tokens = &tokens[1..];
+			}
+			TkRule::Do => {
+				node_toks.push(token.clone());
+				tokens = &tokens[1..];
+				break
+			}
+			_ => {
+				let span = get_span(&node_toks,shenv)?;
+				return Err(err("Expected `do` after loop condition",span,shenv))
+			}
+		}
+	}
+
+	if tokens_iter.peek().is_none() {
+		return Ok(None)
+	}
+
+	let (used,lists) = get_lists(tokens, shenv);
+	for list in &lists {
+		node_toks.extend(list.tokens().clone());
+	}
+	tokens = &tokens[used..];
+	body = lists;
+	tokens_iter = tokens.iter().peekable();
+
+	let mut closed = false;
+	while let Some(token) = tokens_iter.next() {
+		match token.rule() {
+			TkRule::Sep | TkRule::Whitespace => {
+				node_toks.push(token.clone());
+				tokens = &tokens[1..];
+				if closed { break }
+			}
+			TkRule::Done => {
+				closed = true;
+				node_toks.push(token.clone());
+				tokens = &tokens[1..];
+			}
+			_ => {
+				let span = get_span(&node_toks,shenv)?;
+				return Err(err("Unexpected token in loop",span,shenv))
+			}
+		}
+	}
+
+	if !closed {
+		let span = get_span(&node_toks,shenv)?;
+		return Err(err("Expected `done` to close loop",span,shenv))
+	}
+
+	let span = get_span(&node_toks, shenv)?;
+	let node = Node {
+		node_rule: NdRule::Loop { kind, cond, body },
+		tokens: node_toks,
+		span,
+		flags: NdFlag::empty()
+	};
+
+	log!(DEBUG, node);
+	Ok(Some(node))
+});
+
+ndrule_def!(FuncDef, shenv, |tokens: &[Token], shenv: &mut ShEnv| {
 	let mut tokens_iter = tokens.iter();
 	let mut node_toks = vec![];
 	let name: Token;
@@ -307,7 +673,7 @@ ndrule_def!(FuncDef, |tokens: &[Token]| {
 		return Ok(None)
 	}
 
-	let span = get_span(&node_toks)?;
+	let span = get_span(&node_toks,shenv)?;
 	let node = Node {
 		node_rule: NdRule::FuncDef { name, body },
 		tokens: node_toks,
@@ -317,7 +683,7 @@ ndrule_def!(FuncDef, |tokens: &[Token]| {
 	Ok(Some(node))
 });
 
-ndrule_def!(Subshell, |tokens: &[Token]| {
+ndrule_def!(Subshell, shenv, |tokens: &[Token], shenv: &mut ShEnv| {
 	let mut tokens_iter = tokens.iter();
 	let mut node_toks = vec![];
 	let mut argv = vec![];
@@ -350,27 +716,29 @@ ndrule_def!(Subshell, |tokens: &[Token]| {
 					TkRule::RedirOp => {
 						node_toks.push(token.clone());
 						// Get the raw redirection text, e.g. "1>&2" or "2>" or ">>" or something
-						let redir_raw = token.span().get_slice();
+						let redir_raw = shenv.input_slice(token.span());
 						let mut redir_bldr = RedirBldr::from_str(&redir_raw).unwrap();
 						// If there isn't an FD target, get the next token and use it as the filename
 						if redir_bldr.tgt().is_none() {
 							if let Some(filename) = tokens_iter.next() {
 								// Make sure it's a word and not an operator or something
-								if !matches!(filename.rule(), TkRule::SQuote | TkRule::DQuote | TkRule::Ident | TkRule::Keyword) {
+								if !matches!(filename.rule(), TkRule::SQuote | TkRule::DQuote | TkRule::Ident) || KEYWORDS.contains(&filename.rule()) {
 									let mut err = ShErr::simple(ShErrKind::ParseErr, "Did not find a target for this redirection");
-									err.blame(token.span().clone());
+									let input = shenv.input_slice(token.span()).to_string();
+									err.blame(input, token.span());
 									return Err(err)
 								}
 								node_toks.push(filename.clone());
 								// Construct the Path object
-								let filename_raw = filename.span().get_slice();
+								let filename_raw = shenv.input_slice(filename.span()).to_string();
 								let filename_path = PathBuf::from(filename_raw);
 								let tgt = RedirTarget::File(filename_path);
 								// Update the builder
 								redir_bldr = redir_bldr.with_tgt(tgt);
 							} else {
 								let mut err = ShErr::simple(ShErrKind::ParseErr, "Did not find a target for this redirection");
-								err.blame(token.span().clone());
+								let input = shenv.input_slice(token.span()).to_string();
+								err.blame(input, token.span());
 								return Err(err)
 							}
 						}
@@ -379,7 +747,7 @@ ndrule_def!(Subshell, |tokens: &[Token]| {
 					_ => break
 				}
 			}
-			let span = get_span(&node_toks)?;
+			let span = get_span(&node_toks,shenv)?;
 			let node = Node {
 				node_rule: NdRule::Subshell { body, argv, redirs },
 				tokens: node_toks,
@@ -394,7 +762,7 @@ ndrule_def!(Subshell, |tokens: &[Token]| {
 	Ok(None)
 });
 
-ndrule_def!(Pipeline, |mut tokens: &[Token]| {
+ndrule_def!(Pipeline, shenv, |mut tokens: &[Token], shenv: &mut ShEnv| {
 	log!(TRACE, "Parsing pipeline");
 	let mut tokens_iter = tokens.iter().peekable();
 	let mut node_toks = vec![];
@@ -411,7 +779,7 @@ ndrule_def!(Pipeline, |mut tokens: &[Token]| {
 			}
 			_ => { /* Keep going */ }
 		}
-		if let Some(mut cmd) = ExprNoPipeline::try_match(tokens)? {
+		if let Some(mut cmd) = ExprNoPipeline::try_match(tokens,shenv)? {
 			// Add sub-node's tokens to our tokens
 			node_toks.extend(cmd.tokens().clone());
 
@@ -422,8 +790,11 @@ ndrule_def!(Pipeline, |mut tokens: &[Token]| {
 			}
 
 			if let NdRule::Command { argv, redirs: _ } = cmd.rule() {
-				if argv.first().is_some_and(|arg| BUILTINS.contains(&arg.to_string().as_str())) {
-					*cmd.flags_mut() |= NdFlag::BUILTIN;
+				if let Some(arg) = argv.first() {
+					let slice = shenv.input_slice(arg.span().clone());
+					if BUILTINS.contains(&slice) {
+						*cmd.flags_mut() |= NdFlag::BUILTIN;
+					}
 				}
 			}
 			// Push sub-node
@@ -458,7 +829,7 @@ ndrule_def!(Pipeline, |mut tokens: &[Token]| {
 	if node_toks.is_empty() {
 		return Ok(None)
 	}
-	let span = get_span(&node_toks)?;
+	let span = get_span(&node_toks,shenv)?;
 	let node = Node {
 		node_rule: NdRule::Pipeline { cmds },
 		tokens: node_toks,
@@ -468,7 +839,7 @@ ndrule_def!(Pipeline, |mut tokens: &[Token]| {
 	Ok(Some(node))
 });
 
-ndrule_def!(Command, |tokens: &[Token]| {
+ndrule_def!(Command, shenv, |tokens: &[Token], shenv: &mut ShEnv| {
 	log!(TRACE, "Parsing command");
 	let mut tokens = tokens.iter().peekable();
 	let mut node_toks = vec![];
@@ -495,40 +866,49 @@ ndrule_def!(Command, |tokens: &[Token]| {
 			}
 			TkRule::RedirOp => {
 				// Get the raw redirection text, e.g. "1>&2" or "2>" or ">>" or something
-				let redir_raw = token.span().get_slice();
+				let redir_raw = shenv.input_slice(token.span()).to_string();
 				let mut redir_bldr = RedirBldr::from_str(&redir_raw).unwrap();
 				// If there isn't an FD target, get the next token and use it as the filename
 				if redir_bldr.tgt().is_none() {
 					if let Some(filename) = tokens.next() {
 						// Make sure it's a word and not an operator or something
-						if !matches!(filename.rule(), TkRule::SQuote | TkRule::DQuote | TkRule::Ident | TkRule::Keyword) {
+						if !matches!(filename.rule(), TkRule::SQuote | TkRule::DQuote | TkRule::Ident) || KEYWORDS.contains(&filename.rule()) {
 							let mut err = ShErr::simple(ShErrKind::ParseErr, "Did not find a target for this redirection");
-							err.blame(token.span().clone());
+							let input = shenv.input_slice(token.span()).to_string();
+							err.blame(input, token.span());
 							return Err(err)
 						}
 						node_toks.push(filename.clone());
 						// Construct the Path object
-						let filename_raw = filename.span().get_slice();
+						let filename_raw = shenv.input_slice(filename.span()).to_string();
 						let filename_path = PathBuf::from(filename_raw);
 						let tgt = RedirTarget::File(filename_path);
 						// Update the builder
 						redir_bldr = redir_bldr.with_tgt(tgt);
 					} else {
 						let mut err = ShErr::simple(ShErrKind::ParseErr, "Did not find a target for this redirection");
-						err.blame(token.span().clone());
+						let input = shenv.input_slice(token.span()).to_string();
+						err.blame(input, token.span());
 						return Err(err)
 					}
 				}
 				redirs.push(redir_bldr.build());
 			}
 			TkRule::Sep => break,
-			_ => unreachable!("Found this rule: {:?}", token.rule())
+			_ => return Err(
+				ShErr::full(
+					ShErrKind::ParseErr,
+					format!("Unexpected token in command rule: {:?}", token.rule()),
+					shenv.get_input(),
+					get_span(&node_toks,shenv)?
+				)
+			)
 		}
 	}
 	if node_toks.is_empty() {
 		return Ok(None)
 	}
-	let span = get_span(&node_toks)?;
+	let span = get_span(&node_toks,shenv)?;
 	if !argv.is_empty() {
 		let node = Node {
 			node_rule: NdRule::Command { argv, redirs },
@@ -542,7 +922,7 @@ ndrule_def!(Command, |tokens: &[Token]| {
 	}
 });
 
-ndrule_def!(Assignment, |tokens: &[Token]| {
+ndrule_def!(Assignment, shenv, |tokens: &[Token], shenv: &mut ShEnv| {
 	log!(TRACE, "Parsing assignment");
 	let mut tokens = tokens.into_iter().peekable();
 	let mut node_toks = vec![];
@@ -559,11 +939,11 @@ ndrule_def!(Assignment, |tokens: &[Token]| {
 	if tokens.peek().is_some() {
 		let tokens_vec: Vec<Token> = tokens.into_iter().map(|token| token.clone()).collect();
 		let tokens_slice = &tokens_vec;
-		let cmd = Command::try_match(tokens_slice)?.map(|cmd| Box::new(cmd));
+		let cmd = Command::try_match(tokens_slice,shenv)?.map(|cmd| Box::new(cmd));
 		if let Some(ref cmd) = cmd {
 			node_toks.extend(cmd.tokens().clone());
 		}
-		let span = get_span(&node_toks)?;
+		let span = get_span(&node_toks,shenv)?;
 		let node = Node {
 			node_rule: NdRule::Assignment { assignments, cmd },
 			tokens: node_toks,
@@ -572,7 +952,7 @@ ndrule_def!(Assignment, |tokens: &[Token]| {
 		};
 		return Ok(Some(node))
 	} else {
-		let span = get_span(&node_toks)?;
+		let span = get_span(&node_toks,shenv)?;
 		let node = Node {
 			node_rule: NdRule::Assignment { assignments, cmd: None },
 			tokens: node_toks,

src/prelude.rs

@@ -97,12 +97,15 @@ pub use crate::{
 		},
 		sys::{
 			self,
+			sh_quit,
+			read_to_string,
 			write_err,
 			write_out,
 			c_pipe,
 			execvpe
 		},
 		error::{
+			ResultExt,
 			ShErrKind,
 			ShErr,
 			ShResult
@@ -114,6 +117,7 @@ pub use crate::{
 		pwd::pwd,
 		read::read_builtin,
 		alias::alias,
+		control_flow::sh_flow,
 		jobctl::{
 			continue_job,
 			jobs
@@ -140,7 +144,10 @@ pub use crate::{
 		exec_ctx::ExecFlags,
 		shenv::ShEnv
 	},
-	execute::Executor,
+	execute::{
+		exec_input,
+		Executor,
+	},
 	parse::{
 		parse::{
 			Node,

src/prompt/highlight.rs

@@ -1,19 +1,22 @@
 use rustyline::highlight::Highlighter;
 use sys::get_bin_path;
 
-use crate::prelude::*;
+use crate::{parse::lex::KEYWORDS, prelude::*};
 
 use super::readline::SynHelper;
 
 impl<'a> Highlighter for SynHelper<'a> {
 	fn highlight<'l>(&self, line: &'l str, pos: usize) -> std::borrow::Cow<'l, str> {
+		let mut shenv_clone = self.shenv.clone();
+		shenv_clone.new_input(line);
+
 		let mut result = String::new();
-		let mut tokens = Lexer::new(Rc::new(line.to_string())).lex().into_iter();
+		let mut tokens = Lexer::new(line.to_string(),&mut shenv_clone).lex().into_iter();
 		let mut is_command = true;
 		let mut in_array = false;
 
 		while let Some(token) = tokens.next() {
-			let raw = token.to_string();
+			let raw = token.as_raw(&mut shenv_clone);
 			match token.rule() {
 				TkRule::Comment => {
 					let styled = &raw.styled(Style::BrightBlack);
@@ -35,7 +38,7 @@ impl<'a> Highlighter for SynHelper<'a> {
 					let rebuilt = format!("{styled}()");
 					result.push_str(&rebuilt);
 				}
-				TkRule::Keyword => {
+				_ if KEYWORDS.contains(&token.rule()) => {
 					if &raw == "for" {
 						in_array = true;
 					}
@@ -76,7 +79,7 @@ impl<'a> Highlighter for SynHelper<'a> {
 						result.push_str(&raw);
 
 					} else if is_command {
-						if get_bin_path(&token.to_string(), self.shenv).is_some() ||
+						if get_bin_path(&token.as_raw(&mut shenv_clone), self.shenv).is_some() ||
 						self.shenv.logic().get_alias(&raw).is_some() ||
 						self.shenv.logic().get_function(&raw).is_some() ||
 						BUILTINS.contains(&raw.as_str()) {

src/prompt/mod.rs

@@ -4,6 +4,7 @@ use rustyline::{config::Configurer, history::{DefaultHistory, History}, ColorMod
 
 pub mod readline;
 pub mod highlight;
+pub mod validate;
 
 fn init_rl<'a>(shenv: &'a mut ShEnv) -> Editor<SynHelper<'a>, DefaultHistory> {
 	let hist_path = std::env::var("FERN_HIST").unwrap_or_default();
@@ -25,7 +26,7 @@ fn init_rl<'a>(shenv: &'a mut ShEnv) -> Editor<SynHelper<'a>, DefaultHistory> {
 	editor
 }
 
-pub fn read_line<'a>(shenv: &'a mut ShEnv) -> ShResult<String> {
+pub fn read_line(shenv: &mut ShEnv) -> ShResult<String> {
 	log!(TRACE, "Entering prompt");
 	let prompt = "$ ".styled(Style::Green | Style::Bold);
 	let mut editor = init_rl(shenv);

src/prompt/readline.rs

@@ -33,11 +33,6 @@ impl<'a> SynHelper<'a> {
 	}
 }
 
-impl<'a> Validator for SynHelper<'a> {
-	fn validate(&self, ctx: &mut rustyline::validate::ValidationContext) -> rustyline::Result<rustyline::validate::ValidationResult> {
-		Ok(ValidationResult::Valid(None))
-	}
-}
 
 
 impl<'a> Completer for SynHelper<'a> {

src/prompt/validate.rs

@@ -0,0 +1,115 @@
+use rustyline::validate::{ValidationResult, Validator};
+
+use crate::prelude::*;
+
+use super::readline::SynHelper;
+
+pub fn check_delims(line: &str) -> bool {
+	let mut delim_stack = vec![];
+	let mut chars = line.chars();
+	let mut in_quote = None; // Tracks which quote type is open (`'` or `"`)
+
+	while let Some(ch) = chars.next() {
+		match ch {
+			'{' | '(' | '[' if in_quote.is_none() => delim_stack.push(ch),
+			'}' if in_quote.is_none() && delim_stack.pop() != Some('{') => return false,
+			')' if in_quote.is_none() && delim_stack.pop() != Some('(') => return false,
+			']' if in_quote.is_none() && delim_stack.pop() != Some('[') => return false,
+			'"' | '\'' => {
+				if in_quote == Some(ch) {
+					in_quote = None;
+				} else if in_quote.is_none() {
+					in_quote = Some(ch);
+				}
+			}
+			'\\' => { chars.next(); } // Skip next character if escaped
+			_ => {}
+		}
+	}
+
+	delim_stack.is_empty() && in_quote.is_none()
+}
+
+pub fn check_keywords(line: &str, shenv: &mut ShEnv) -> bool {
+	use TkRule::*;
+	let mut expecting: Vec<Vec<TkRule>> = vec![];
+	let mut tokens = Lexer::new(line.to_string(),shenv).lex().into_iter();
+
+	while let Some(token) = tokens.next() {
+		match token.rule() {
+			If => {
+				expecting.push(vec![Then]);
+			}
+			Then => {
+				if let Some(frame) = expecting.pop() {
+					if frame.contains(&Then) {
+						expecting.push(vec![Elif, Else, Fi])
+					} else { return false }
+				} else { return false }
+			}
+			Elif => {
+				if let Some(frame) = expecting.pop() {
+					if frame.contains(&Elif) {
+						expecting.push(vec![Then])
+					} else { return false }
+				} else { return false }
+			}
+			Else => {
+				if let Some(frame) = expecting.pop() {
+					if frame.contains(&Else) {
+						expecting.push(vec![Fi])
+					} else { return false }
+				} else { return false }
+			}
+			Fi => {
+				if let Some(frame) = expecting.pop() {
+					if frame.contains(&Fi) {
+						/* Do nothing */
+					} else { return false }
+				} else { return false }
+			}
+			While | Until | For | Select => {
+				expecting.push(vec![Do])
+			}
+			Do => {
+				if let Some(frame) = expecting.pop() {
+					if frame.contains(&Do) {
+						expecting.push(vec![Done])
+					} else { return false }
+				} else { return false }
+			}
+			Done => {
+				if let Some(frame) = expecting.pop() {
+					if frame.contains(&Done) {
+						/* Do nothing */
+					} else { return false }
+				} else { return false }
+			}
+			Case => {
+				expecting.push(vec![Esac])
+			}
+			Esac => {
+				if let Some(frame) = expecting.pop() {
+					if frame.contains(&Esac) {
+						/* Do nothing */
+					} else { return false }
+				} else { return false }
+			}
+			_ => { /* Do nothing */ }
+		}
+	}
+
+	expecting.is_empty()
+}
+
+impl<'a> Validator for SynHelper<'a> {
+	fn validate(&self, ctx: &mut rustyline::validate::ValidationContext) -> rustyline::Result<rustyline::validate::ValidationResult> {
+		let input = ctx.input();
+		let mut shenv_clone = self.shenv.clone();
+		match check_delims(input) && check_keywords(input, &mut shenv_clone) {
+			true => Ok(ValidationResult::Valid(None)),
+			false => Ok(ValidationResult::Incomplete),
+		}
+
+	}
+}

src/shellenv/input.rs

@@ -0,0 +1,61 @@
+use std::cell::Ref;
+
+use crate::prelude::*;
+
+#[derive(Clone,Debug)]
+pub struct InputMan {
+	input: Option<String>,
+	spans: Vec<Rc<RefCell<Span>>>,
+}
+
+impl InputMan {
+	pub fn new() -> Self {
+		Self { input: None, spans: vec![] }
+	}
+	pub fn clear(&mut self) {
+		*self = Self::new();
+	}
+	pub fn new_input(&mut self, input: &str) {
+		self.input = Some(input.to_string())
+	}
+	pub fn get_input(&self) -> Option<&String> {
+		self.input.as_ref()
+	}
+	pub fn get_input_mut(&mut self) -> Option<&mut String> {
+		self.input.as_mut()
+	}
+	pub fn new_span(&mut self, start: usize, end: usize) -> Rc<RefCell<Span>> {
+		if let Some(_input) = &self.input {
+			let span = Rc::new(RefCell::new(Span::new(start, end)));
+			self.spans.push(span.clone());
+			span
+		} else {
+			Rc::new(RefCell::new(Span::new(0,0)))
+		}
+	}
+	pub fn spans_mut(&mut self) -> &mut Vec<Rc<RefCell<Span>>> {
+		&mut self.spans
+	}
+	pub fn clamp(&self, span: Rc<RefCell<Span>>) {
+		let mut span = span.borrow_mut();
+		if let Some(input) = &self.input {
+			span.clamp_start(input.len());
+			span.clamp_end(input.len());
+		}
+	}
+	pub fn clamp_all(&self) {
+		for span in &self.spans {
+			self.clamp(span.clone());
+		}
+	}
+	pub fn get_slice(&self, span: Rc<RefCell<Span>>) -> Option<&str> {
+		let span = span.borrow();
+		let mut start = span.start();
+		let end = span.end();
+		if start > end {
+			start = end;
+		}
+
+		self.input.as_ref().map(|s| &s[start..end])
+	}
+}

src/shellenv/mod.rs

@@ -10,6 +10,7 @@ pub mod exec_ctx;
 pub mod meta;
 pub mod shenv;
 pub mod vars;
+pub mod input;
 
 /// Calls attach_tty() on the shell's process group to retake control of the terminal
 pub fn take_term() -> ShResult<()> {

src/shellenv/shenv.rs

@@ -5,6 +5,7 @@ pub struct ShEnv {
 	vars: shellenv::vars::VarTab,
 	logic: shellenv::logic::LogTab,
 	meta: shellenv::meta::MetaTab,
+	input_man: shellenv::input::InputMan,
 	ctx: shellenv::exec_ctx::ExecCtx
 }
 
@@ -14,6 +15,7 @@ impl ShEnv {
 			vars: shellenv::vars::VarTab::new(),
 			logic: shellenv::logic::LogTab::new(),
 			meta: shellenv::meta::MetaTab::new(),
+			input_man: shellenv::input::InputMan::new(),
 			ctx: shellenv::exec_ctx::ExecCtx::new(),
 		}
 	}
@@ -26,6 +28,58 @@ impl ShEnv {
 	pub fn meta(&self) -> &shellenv::meta::MetaTab {
 		&self.meta
 	}
+	pub fn input_slice(&self, span: Rc<RefCell<Span>>) -> &str {
+		&self.input_man.get_slice(span).unwrap_or_default()
+	}
+	pub fn expand_input(&mut self, new: &str, repl_span: Rc<RefCell<Span>>) -> Vec<Token> {
+		let saved_spans = self.input_man.spans_mut().clone();
+		let mut new_tokens = Lexer::new(new.to_string(), self).lex();
+		*self.input_man.spans_mut() = saved_spans;
+
+		let offset = repl_span.borrow().start();
+		for token in new_tokens.iter_mut() {
+			token.span().borrow_mut().shift(offset as isize);
+		}
+
+		let repl_start = repl_span.borrow().start();
+		let repl_end = repl_span.borrow().end();
+		let range = repl_start..repl_end;
+
+		if let Some(ref mut input) = self.input_man.get_input_mut() {
+			let old = &input[range.clone()];
+			let delta: isize = new.len() as isize - old.len() as isize;
+			input.replace_range(range, new);
+			let expanded = input.clone();
+			log!(DEBUG, expanded);
+
+			for span in self.input_man.spans_mut() {
+				let mut span_mut = span.borrow_mut();
+				if span_mut.start() > repl_start {
+					span_mut.shift(delta);
+				}
+			}
+			for token in &new_tokens {
+				self.input_man.spans_mut().push(token.span());
+			}
+		}
+		self.input_man.clamp_all();
+		new_tokens
+	}
+	pub fn new_input(&mut self, input: &str) {
+		self.input_man.clear();
+		self.input_man.new_input(input);
+	}
+	pub fn get_input(&self) -> String {
+		let input = self.input_man.get_input().map(|s| s.to_string()).unwrap_or_default();
+		log!(DEBUG, input);
+		input
+	}
+	pub fn inputman(&self) -> &shellenv::input::InputMan {
+		&self.input_man
+	}
+	pub fn inputman_mut(&mut self) -> &mut shellenv::input::InputMan {
+		&mut self.input_man
+	}
 	pub fn meta_mut(&mut self) -> &mut shellenv::meta::MetaTab {
 		&mut self.meta
 	}