Added define operator

src/parser/parsererror.rs

@@ -15,7 +15,6 @@ pub enum ParserError {
 	ExtraCloseParen,
 	EmptyGroup,
 	Syntax,
-	Undefined(String),
 	BadNumber
 }
 
@@ -34,9 +33,6 @@ impl ToString for ParserError {
 			ParserError::Syntax => {
 				String::from("Syntax")
 			},
-			ParserError::Undefined(s) => {
-				format!("\"{s}\" isn't defined")
-			},
 			ParserError::BadNumber => {
 				String::from("Invalid number")
 			}

src/parser/pretoken.rs

@@ -68,13 +68,15 @@ impl PreToken {
 				}
 
 				let r = Quantity::new_rational_from_string(&s);
+
 				if r.is_none() {
 					return Err((l, ParserError::BadNumber))
 				}
+
 				return Ok(Token::Quantity(r.unwrap()));
 			},
 
-			PreToken::PreWord(l, s) => {
+			PreToken::PreWord(_l, s) => {
 
 				let c = Constant::from_string(&s);
 				if c.is_some() { return Ok(Token::Constant(c.unwrap())); }
@@ -84,8 +86,7 @@ impl PreToken {
 
 				let c = context.get_variable(&s);
 				if c.is_some() { return Ok(Token::Variable(s)); }
-
-				return Err((l, ParserError::Undefined(s)));
+				return Ok(Token::Variable(s));
 			}
 
 			PreToken::Container(v) => { return Ok(v); }

src/parser/stage/tokenize.rs

@@ -136,7 +136,7 @@ pub fn tokenize(input: &String) -> VecDeque<PreToken> {
 
 			// Operator
 			'*'|'×'|'/'|'÷'|
-			'^'|'!'|'%'
+			'^'|'!'|'%'|'='
 			=> {
 				match &mut t {
 					Some(PreToken::PreOperator(_, val)) => { val.push(c); },

src/parser/token/operator.rs

@@ -11,7 +11,8 @@ use super::Function;
 #[derive(Clone)]
 #[repr(usize)]
 pub enum Operator {
-	ModuloLong = 0, // Mod invoked with "mod"
+	Define = 0, // Variable and function definition
+	ModuloLong, // Mod invoked with "mod"
 	DivideLong,
 	UnitConvert,
 	Subtract,
@@ -68,6 +69,7 @@ impl Operator {
 		}
 
 		return match s {
+			"="      => {Some( Operator::Define )},
 			"+"      => {Some( Operator::Add )},
 			"-"      => {Some( Operator::Subtract )},
 			"neg"    => {Some( Operator::Negative )},
@@ -166,6 +168,7 @@ impl Operator {
 			| Operator::Power
 			| Operator::ModuloLong
 			| Operator::UnitConvert
+			| Operator::Define
 			=> { Token::Operator(self, args) },
 		}
 	}
@@ -201,6 +204,14 @@ impl Operator {
 			Operator::Divide |
 			Operator::Subtract => { panic!() }
 
+			Operator::Define => {
+				return format!(
+					"{} = {}",
+					self.add_parens_to_arg(&args[0]),
+					self.add_parens_to_arg(&args[1])
+				);
+			},
+
 			Operator::Flip => {
 				return format!("{}⁻¹", Operator::Divide.add_parens_to_arg(&args[0]));
 			},

src/parser/token/token.rs

@@ -37,6 +37,13 @@ impl Token {
 		}
 	}
 
+	pub fn is_quantity(&self) -> bool {
+		match self {
+			Token::Quantity(_) => true,
+			_ => false
+		}
+	}
+
 	#[inline(always)]
 	pub fn get_args_mut(&mut self) -> Option<&mut VecDeque<Token>> {
 		match self {
@@ -46,14 +53,34 @@ impl Token {
 	}
 
 	#[inline(always)]
-	pub fn get_at_coords<'a>(g: &'a mut Token, coords: &Vec<usize>) -> &'a mut Token {
-		let mut h = &mut *g;
-
-		for t in coords.iter() {
-			let inner = h.get_args_mut().unwrap();
-			h = &mut inner[*t];
+	pub fn get_args(&self) -> Option<&VecDeque<Token>> {
+		match self {
+			Token::Operator(_, ref a) => Some(a),
+			_ => None
 		}
+	}
 
-		return h;
+	#[inline(always)]
+	pub fn get_at_coords<'a, 'b, I>(&'a self, coords: I) -> Option<&'a Token>
+	where I: IntoIterator<Item = &'b usize> + Sized {
+		let mut g = self;
+		for t in coords.into_iter() {
+			let args = g.get_args();
+			let Some(args) = args else { return None; };
+			g = &args[*t];
+		}
+		return Some(g);
+	}
+
+	#[inline(always)]
+	pub fn get_at_coords_mut<'a, 'b, I>(&'a mut self, coords: I) -> Option<&'a mut Token>
+	where I: IntoIterator<Item = &'b usize> + Sized {
+		let mut g = self;
+		for t in coords.into_iter() {
+			let args = g.get_args_mut();
+			let Some(args) = args else { return None; };
+			g = &mut args[*t];
+		}
+		return Some(g);
 	}
 }