Fixed syntax error location

src/parser.rs

@@ -83,8 +83,25 @@ impl Token {
 			Token::Number(_l, _) |
 			Token::Constant(_l, _, _)
 			=> panic!(),
+			_ => panic!()
+		}
+	}
 
+	#[inline(always)]
+	pub fn get_mut_line_location(&mut self) -> &mut LineLocation {
+		match self {
+			Token::PreNumber(l, _) |
+			Token::PreWord(l, _) |
+			Token::PreOperator(l, _) |
+			Token::PreGroupStart(l) |
+			Token::PreGroupEnd(l) |
+			Token::PreGroup(l, _)
+			=> l,
 
+			// These have a line location, but we shouldn't ever need to get it.
+			Token::Number(_l, _) |
+			Token::Constant(_l, _, _)
+			=> panic!(),
 			_ => panic!()
 		}
 	}
@@ -261,6 +278,7 @@ pub enum ParserError {
 pub fn evaluate(s: &String) -> Result<Token, (LineLocation, ParserError)> {
 
 	let tokens = p_tokenize(s);
+	let (_, tokens) = p_find_subs(tokens);
 	let mut g = p_groupify(tokens)?;
 	g = p_treeify(g)?;
 	g = p_evaluate(g)?;
@@ -274,7 +292,7 @@ pub fn substitute(s: &String) -> String{
 	let mut new_s = s.clone();
 
 	let tokens = p_tokenize(s);
-	let subs = p_find_subs(tokens);
+	let (subs, _) = p_find_subs(tokens);
 
 	for r in subs.iter() {
 		new_s.replace_range(

src/parser/find_subs.rs

@@ -7,60 +7,80 @@ use crate::parser::LineLocation;
 
 pub fn p_find_subs(
 	mut g: VecDeque<Token>,
-) -> Vec<(LineLocation, String)> {
+) -> (
+	Vec<(LineLocation, String)>,
+	VecDeque<Token>
+) {
 
+	// Array of replacements
 	let mut r: Vec<(LineLocation, String)> = Vec::with_capacity(8);
 
+	// New token array, with updated locations
+	let mut n: VecDeque<Token> = VecDeque::with_capacity(g.len());
+
+	let mut offset: usize = 0;
+
 	while g.len() > 0 {
 		// Read in reverse. Very important!
-		let t = g.pop_back().unwrap();
+		let mut t = g.pop_back().unwrap();
 
-		match &t {
+		let target: Option<&str> = match &mut t {
-
+			Token::PreOperator(_, o) => {
-			Token::PreOperator(l, o) => {
 				match o {
-					Operator::Multiply => { r.push((l.clone(), String::from("×"))); },
+					Operator::Multiply => {Some("×")},
-					Operator::Divide => { r.push((l.clone(), String::from("÷"))); },
+					Operator::Divide => {Some("÷")},
-					_ => {}
+					_ => {None}
 				}
 			},
 
-			Token::PreWord(l, s) => {
+			Token::PreWord(_, s) => {
 				match &s[..] {
-
 					// Greek letters
-					"alpha"   => { r.push((l.clone(), String::from("α"))); },
+					"alpha"   => {Some("α")},
-					"beta"    => { r.push((l.clone(), String::from("β"))); },
+					"beta"    => {Some("β")},
-					"gamma"   => { r.push((l.clone(), String::from("γ"))); },
+					"gamma"   => {Some("γ")},
-					"delta"   => { r.push((l.clone(), String::from("δ"))); },
+					"delta"   => {Some("δ")},
-					"epsilon" => { r.push((l.clone(), String::from("ε"))); },
+					"epsilon" => {Some("ε")},
-					"zeta"    => { r.push((l.clone(), String::from("ζ"))); },
+					"zeta"    => {Some("ζ")},
-					"eta"     => { r.push((l.clone(), String::from("η"))); },
+					"eta"     => {Some("η")},
-					"theta"   => { r.push((l.clone(), String::from("θ"))); },
+					"theta"   => {Some("θ")},
-					"iota"    => { r.push((l.clone(), String::from("ι"))); },
+					"iota"    => {Some("ι")},
-					//"kappa"   => { r.push((l.clone(), String::from("κ"))); },
+					"kappa"   => {Some("κ")},
-					"lambda"  => { r.push((l.clone(), String::from("λ"))); },
+					"lambda"  => {Some("λ")},
-					"mu"      => { r.push((l.clone(), String::from("μ"))); },
+					"mu"      => {Some("μ")},
-					"nu"      => { r.push((l.clone(), String::from("ν"))); },
+					"nu"      => {Some("ν")},
-					"xi"      => { r.push((l.clone(), String::from("ξ"))); },
+					"xi"      => {Some("ξ")},
-					//"omicron" => { r.push((l.clone(), String::from("ο"))); },
+					"omicron" => {Some("ο")},
-					"pi"      => { r.push((l.clone(), String::from("π"))); },
+					"pi"      => {Some("π")},
-					"rho"     => { r.push((l.clone(), String::from("ρ"))); },
+					"rho"     => {Some("ρ")},
-					"sigma"   => { r.push((l.clone(), String::from("σ"))); },
+					"sigma"   => {Some("σ")},
-					"tau"     => { r.push((l.clone(), String::from("τ"))); },
+					"tau"     => {Some("τ")},
-					//"upsilon" => { r.push((l.clone(), String::from("υ"))); },
+					"upsilon" => {Some("υ")},
-					"phi"     => { r.push((l.clone(), String::from("φ"))); },
+					"phi"     => {Some("φ")},
-					"chi"     => { r.push((l.clone(), String::from("χ"))); },
+					"chi"     => {Some("χ")},
-					"psi"     => { r.push((l.clone(), String::from("ψ"))); },
+					"psi"     => {Some("ψ")},
-					"omega"   => { r.push((l.clone(), String::from("ω"))); }
+					"omega"   => {Some("ω")}
 
-					_ => {}
+					_ => {None}
+				}
+			},
+
+			_ => {None}
+		};
+
+		if target.is_none() {
+			// Even if nothing changed, we need to update token location
+			let l = t.get_mut_line_location();
+			*l = LineLocation{pos: l.pos - offset, len: l.len};
+		} else {
+			let target = target.unwrap();
+			let l = t.get_mut_line_location();
+			r.push((l.clone(), String::from(target)));
+			*l = LineLocation{ pos: l.pos - offset, len: target.chars().count()};
+			offset += l.len - target.chars().count();
+		}
+		n.push_front(t);
 	}
 
-			}
+	return (r, n);
-			_ => {}
-		}
-	}
-
-	return r;
 }