Added group parsing

src/main.rs

@@ -0,0 +1,100 @@
+use std::io;
+use std::io::Write;
+//use std::io::Read;
+use std::sync::Arc;
+use std::sync::atomic::{AtomicBool, Ordering};
+
+use termcolor::{
+	Color,
+	ColorChoice,
+	ColorSpec,
+	StandardStream,
+	WriteColor
+};
+
+pub mod tokenize;
+
+const PROMPT_PREFIX: &str = "==> ";
+
+/// Show a prompt and save trimmed input to `input`.
+///
+/// # Arguments:
+/// 
+/// * `stdout`: Where we should write the prompt
+/// * `input`: Where we should save user input
+///
+/// # Example usage:
+/// ```
+/// let mut input = String::new();
+/// prompt(&mut stdout, &mut input)?;
+/// ```
+fn prompt(
+	stdout: &mut StandardStream,
+	input: &mut String
+) -> Result<(), std::io::Error> {
+
+	// Print colored prompt prefix
+	stdout.set_color(ColorSpec::new().set_fg(Some(Color::Blue)))?;
+	write!(*stdout, "{PROMPT_PREFIX}")?;
+	stdout.reset()?;  // reset colors
+	stdout.flush()?;  // flush, we didn't print a full line yet.
+
+	// Ask for input
+	io::stdin().read_line(input)?;
+
+	// If this input doesn't end with a newline,
+	// the user terminated this prompt with ctrl-d.
+	// Add a newline to keep spacing consistent,
+	// and clear the input.
+	if match input.chars().last() {
+			Some(val) => val != '\n',
+			None => true
+	} {
+		write!(*stdout, "\n")?;
+		input.clear();
+	} else {
+		(*input) = input.trim().to_string();
+	}
+
+	Ok(())
+}
+
+fn main() -> Result<(), std::io::Error> {
+
+	let mut stdout = StandardStream::stdout(ColorChoice::Always);
+
+	let term = Arc::new(AtomicBool::new(false));
+	signal_hook::flag::register(signal_hook::consts::SIGINT, Arc::clone(&term))?;
+	while !term.load(Ordering::Relaxed) {
+		let mut input = String::with_capacity(64);
+		prompt(&mut stdout, &mut input).expect("Could not show prompt");
+		let input = input;
+
+		// Ignore empty input
+		if input == "" {
+			stdout.flush()?;
+			continue;
+		}
+
+		// Tokenize input.
+		// Fail if we encounter invalid characters.
+		let tokens = match tokenize::tokenize(&input) {
+			Ok(v) => v,
+			Err(_) => {
+				continue;
+			}
+		};
+
+
+		stdout.set_color(ColorSpec::new().set_fg(Some(Color::Green)))?;
+		write!(stdout, "\n  => ")?;
+		stdout.reset()?;
+		write!(stdout, "Got {input}\n\n\n")?;
+
+		writeln!(stdout, "Tokenized: {tokens:#?}")?;
+
+	}
+
+	writeln!(stdout, "Exiting.")?;
+	Ok(())
+}

src/tokenize.rs

@@ -1,11 +1,11 @@
 #[derive(Debug)]
+#[derive(Clone)]
 pub enum Token {
 	Negative,
-	StartGroup,
-	EndGroup,
 	Number(String),
 	Operator(String),
 	Word(String),
+	Group(Vec<Token>),
 }
 
 /// Turn a string into a set of tokens.
@@ -17,22 +17,30 @@ pub enum Token {
 // # Returns:
 // * `Ok(Vec<token>)` if we were successful.
 // * `Err(())` if we couldn't tokenize this string.
-pub fn tokenize(input: &String) -> Result<Vec<Token>, ()> {
-	let mut v: Vec<Token> = Vec::new();
+pub fn tokenize(input: &String) -> Result<Token, ()> {
 	let mut t: Option<Token> = None;
+	let mut g: Vec<Token> = Vec::with_capacity(8);
+	g.push(Token::Group(Vec::with_capacity(8)));
+
+
 	for c in input.chars() {
+		let v_now: &mut Vec<Token> = match g.last_mut().unwrap() {
+			Token::Group(ref mut x) => x,
+			_ => panic!()
+		};
+
 		match c {
 			// Minus sign can be both a Negative and an Operator.
 			// Needs special treatment.
 			'-' => {
-				if t.is_some() { v.push(t.unwrap()); t = None; }
-				match v.last() {
+				if t.is_some() { v_now.push(t.unwrap()); t = None; }
+				match v_now.last() {
 					// If previous token was any of the following,
 					// this is the "minus" operator
 					Some(Token::Number(_)) |
-					Some(Token::EndGroup) |
+					Some(Token::Group(_)) |
 					Some(Token::Word(_)) => {
-						v.push(Token::Operator(String::from(c)));
+						v_now.push(Token::Operator(String::from(c)));
 					},
 
 					// Otherwise, this is a negative sign.
@@ -53,7 +61,7 @@ pub fn tokenize(input: &String) -> Result<Vec<Token>, ()> {
 					// If we're not building a number, finalize
 					// previous token and start one.
 					_ => {
-						if t.is_some() { v.push(t.unwrap()); }
+						if t.is_some() { v_now.push(t.unwrap()); }
 						t = Some(Token::Number(String::from(c)));
 					}
 				};
@@ -72,7 +80,7 @@ pub fn tokenize(input: &String) -> Result<Vec<Token>, ()> {
 					// If we're not building a number, finalize
 					// previous token and start one.
 					_ => {
-						if t.is_some() { v.push(t.unwrap()); }
+						if t.is_some() { v_now.push(t.unwrap()); }
 						t = Some(Token::Word(String::from(c)));
 					}
 				};
@@ -83,24 +91,31 @@ pub fn tokenize(input: &String) -> Result<Vec<Token>, ()> {
 			// Always one character
 			'+' | '*' | '/' | '^' => {
 				// Finalize previous token
-				if t.is_some() { v.push(t.unwrap()); t = None; }
-				v.push(Token::Operator(String::from(c)));
+				if t.is_some() { v_now.push(t.unwrap()); t = None; }
+				v_now.push(Token::Operator(String::from(c)));
 			}
 			
 			// Groups
 			// Always one character
 			'(' => {
-				if t.is_some() { v.push(t.unwrap()); t = None; }
-				v.push(Token::StartGroup);
+				if t.is_some() { v_now.push(t.unwrap()); t = None; }
+				g.push(Token::Group(Vec::with_capacity(8)));
 			},
 			')' => {
-				if t.is_some() { v.push(t.unwrap()); t = None; }
-				v.push(Token::EndGroup);
+				if t.is_some() { v_now.push(t.unwrap()); t = None; }
+				let new_group: Token = g.pop().unwrap();
+
+				let v_now: &mut Vec<Token> = match g.last_mut().unwrap() {
+					Token::Group(ref mut x) => x,
+					_ => panic!()
+				};
+		
+				v_now.push(new_group);
 			},
 
 			// Space. Basic seperator.
 			' ' => {
-				if t.is_some() { v.push(t.unwrap()); t = None; }
+				if t.is_some() { v_now.push(t.unwrap()); t = None; }
 			}
 
 			// Invalid token
@@ -108,6 +123,12 @@ pub fn tokenize(input: &String) -> Result<Vec<Token>, ()> {
 		};
 	}
 
-	if t.is_some() { v.push(t.unwrap()); }
-	return Ok(v);
+	
+	let v_now: &mut Vec<Token> = match g.last_mut().unwrap() {
+		Token::Group(ref mut x) => x,
+		_ => panic!()
+	};
+	if t.is_some() { v_now.push(t.unwrap()); }
+
+	return Ok(Token::Group(v_now.to_vec()));
 }