Added basic evaluation

src/parser.rs

@@ -1,8 +1,10 @@
 mod tokenize;
 mod treeify;
+mod evaluate;
 
 use crate::parser::tokenize::tokenize;
 use crate::parser::treeify::treeify;
+use crate::parser::evaluate::evaluate;
 
 use std::collections::VecDeque;
 
@@ -11,6 +13,11 @@ use std::collections::VecDeque;
 /// 
 /// Tokens starting with `Pre*` are intermediate tokens, and
 /// will never show up in a fully-parsed expression tree.
+
+pub trait Eval {
+	fn eval(&self) -> Token;
+}
+
 #[derive(Debug)]
 pub enum Token {
 
@@ -30,17 +37,144 @@ pub enum Token {
 	/// PreGroups aren't needed once we have a tree.
 	PreGroup(LineLocation, VecDeque<Token>),
 
+	Root(VecDeque<Token>),
 	Number(LineLocation, f64),
 	Multiply(VecDeque<Token>),
 	Divide(VecDeque<Token>),
 	Add(VecDeque<Token>),
-	Subtract(VecDeque<Token>),
 	Factorial(VecDeque<Token>),
 	Negative(VecDeque<Token>),
 	Power(VecDeque<Token>),
 	Modulo(VecDeque<Token>),
 }
 
+impl Eval for Token {
+	fn eval(&self) -> Token {
+		match self {
+			Token::Negative(ref v) => {
+				if v.len() != 1 {panic!()};
+
+				if let Token::Number(l, v) = v[0]{
+					Token::Number(l, -v)
+				} else { panic!(); }
+			},
+
+			Token::Add(ref v) => {
+				let mut sum: f64 = 0f64;
+				let mut new_pos: usize = 0;
+				let mut new_len: usize = 0;
+				for i in v.iter() {
+					if let Token::Number(l, v) = i {
+						let LineLocation{pos, len} = *l;
+						if new_pos == 0 {new_pos = pos};
+						new_len = new_len + len;
+						sum += v;
+					} else {
+						panic!();
+					}
+				}
+
+				Token::Number(
+					LineLocation { pos: new_pos, len: new_len },
+					sum
+				)
+			},
+
+			Token::Multiply(ref v) => {
+				let mut prod: f64 = 1f64;
+				let mut new_pos: usize = 0;
+				let mut new_len: usize = 0;
+				for i in v.iter() {
+					if let Token::Number(l, v) = i {
+						let LineLocation{pos, len} = *l;
+						if new_pos == 0 {new_pos = pos};
+						new_len = new_len + len;
+						prod *= v;
+					} else {
+						panic!();
+					}
+				}
+
+				Token::Number(
+					LineLocation { pos: new_pos, len: new_len },
+					prod
+				)
+			},
+
+			Token::Divide(ref v) => {
+				if v.len() != 2 {panic!()};
+				let a = &v[0];
+				let b = &v[1];
+
+				if let Token::Number(la, va) = a {
+					if let Token::Number(lb, vb) = b {
+						let LineLocation{pos: posa, ..} = *la;
+						let LineLocation{pos: posb, len: lenb} = lb;
+						Token::Number(
+							LineLocation { pos: posa, len: posb - posa + lenb },
+							va/vb
+						)
+					} else { panic!(); }
+				} else { panic!(); }
+			},
+
+			Token::Modulo(ref v) => {
+				if v.len() != 2 {panic!()};
+				let a = &v[0];
+				let b = &v[1];
+
+				if let Token::Number(la, va) = a {
+					if let Token::Number(lb, vb) = b {
+						let LineLocation{pos: posa, ..} = *la;
+						let LineLocation{pos: posb, len: lenb} = lb;
+						Token::Number(
+							LineLocation { pos: posa, len: posb - posa + lenb },
+							va%vb
+						)
+					} else { panic!(); }
+				} else { panic!(); }
+			},
+
+			Token::Power(ref v) => {
+				if v.len() != 2 {panic!()};
+				let a = &v[0];
+				let b = &v[1];
+
+				if let Token::Number(la, va) = a {
+					if let Token::Number(lb, vb) = b {
+						let LineLocation{pos: posa, ..} = *la;
+						let LineLocation{pos: posb, len: lenb} = lb;
+						Token::Number(
+							LineLocation { pos: posa, len: posb - posa + lenb },
+							va.powf(*vb)
+						)
+					} else { panic!(); }
+				} else { panic!(); }
+			},
+
+			Token::Root(ref v) => {
+				if v.len() != 2 {panic!()};
+				let a = &v[0];
+				let b = &v[1];
+
+				if let Token::Number(la, va) = a {
+					if let Token::Number(lb, vb) = b {
+						let LineLocation{pos: posa, ..} = *la;
+						let LineLocation{pos: posb, len: lenb} = lb;
+						Token::Number(
+							LineLocation { pos: posa, len: posb - posa + lenb },
+							va.powf(1f64 / *vb)
+						)
+					} else { panic!(); }
+				} else { panic!(); }
+			},
+
+			Token::Factorial(ref v) => { todo!() },
+			_ => panic!()
+		}
+	}
+}
+
 
 /// Operator types, in order of increasing priority.
 /// The Null operator MUST be equal to zero.
@@ -97,7 +231,8 @@ pub enum ParserError {
 pub fn parse(s: &String) -> Result<Token, (LineLocation, ParserError)> {
 
 	let mut g: Token = tokenize(s)?;
-	treeify(&mut g)?;
+	g = treeify(g)?;
+	g = evaluate(g)?;
 
 	return Ok(g);
 }

src/parser/evaluate.rs

@@ -0,0 +1,95 @@
+use std::collections::VecDeque;
+
+use crate::parser::Token;
+use crate::parser::Eval;
+use crate::parser::LineLocation;
+use crate::parser::ParserError;
+
+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 = match h {
+			Token::Multiply(ref mut v) => v,
+			Token::Divide(ref mut v) => v,
+			Token::Add(ref mut v) => v,
+			Token::Factorial(ref mut v) => v,
+			Token::Negative(ref mut v) => v,
+			Token::Power(ref mut v) => v,
+			Token::Modulo(ref mut v) => v,
+			Token::Root(ref mut v) => v,
+			_ => panic!()
+		};
+
+		h = &mut inner[*t];
+	}
+
+	return h;
+}
+
+
+pub fn evaluate(
+	mut g: Token,
+) -> Result<Token, (LineLocation, ParserError)> {
+
+	let mut coords: Vec<usize> = Vec::with_capacity(16);
+	coords.push(0);
+
+	'outer: loop {
+
+		let mut h = &mut g;
+		for t in coords.iter() {
+			let inner = match h {
+				Token::Multiply(ref mut v) => v,
+				Token::Divide(ref mut v) => v,
+				Token::Add(ref mut v) => v,
+				Token::Factorial(ref mut v) => v,
+				Token::Negative(ref mut v) => v,
+				Token::Power(ref mut v) => v,
+				Token::Modulo(ref mut v) => v,
+				Token::Root(ref mut v) => v,
+				_ => panic!()
+			};
+
+			if *t >= inner.len() {
+				coords.pop();
+				if coords.len() == 0 { break 'outer; }
+
+
+				let p = get_at_coords(&mut g, &coords);
+				let e = p.eval();
+				*p = e;
+
+				let l = coords.pop().unwrap();
+				coords.push(l + 1);
+				continue 'outer;
+			}
+
+			h = &mut inner[*t];
+		}
+
+		match h {
+			Token::Multiply(v) |
+			Token::Divide(v) |
+			Token::Add(v) |
+			Token::Factorial(v) |
+			Token::Negative(v) |
+			Token::Power(v) |
+			Token::Modulo(v)
+			=> {
+				coords.push(0);
+				continue 'outer;
+			},
+
+			Token::Number(_,_) => {
+				let l = coords.pop().unwrap();
+				coords.push(l + 1);
+				continue 'outer;
+			}
+			_ => panic!()
+		};
+	}
+
+
+	return Ok(g);
+}

src/parser/treeify.rs

@@ -18,9 +18,18 @@ fn get_line_location(t: &Token) -> &LineLocation {
 }
 
 #[inline(always)]
-fn select_op(k: Operators, new_token_args: VecDeque<Token>) -> Token {
+fn select_op(k: Operators, mut new_token_args: VecDeque<Token>) -> Token {
 	match k {
-		Operators::Subtract => Token::Subtract(new_token_args),
+		Operators::Subtract => {
+			let a = new_token_args.pop_front().unwrap();
+			let b = new_token_args.pop_front().unwrap();
+
+			Token::Add(
+			VecDeque::from(vec!(
+					a,
+					Token::Negative(VecDeque::from(vec!(b)))
+			)))
+		},
 		Operators::Add => Token::Add(new_token_args),
 		Operators::Divide => Token::Divide(new_token_args),
 		Operators::Multiply => Token::Multiply(new_token_args),
@@ -114,8 +123,8 @@ fn treeify_binary(
 			let mut left = g_inner.remove(i-1).unwrap();
 			let this = g_inner.remove(i-1).unwrap();
 			let mut right = g_inner.remove(i-1).unwrap();
-			if let Token::PreGroup(_, _) = right { treeify(&mut right)?; }
+			if let Token::PreGroup(_, _) = right { right = inner_treeify(right)?; }
-			if let Token::PreGroup(_, _) = left { treeify(&mut left)?; }
+			if let Token::PreGroup(_, _) = left { left = inner_treeify(left)?; }
 
 			let k = match this {
 				Token::PreOperator(_, k) => k,
@@ -209,7 +218,7 @@ fn treeify_unaryleft(
 		if right_val.is_none() || this_val > right_val.unwrap() {
 			let this = g_inner.remove(i).unwrap();
 			let mut right = g_inner.remove(i).unwrap();
-			if let Token::PreGroup(_, _) = right { treeify(&mut right)?; }
+			if let Token::PreGroup(_, _) = right { right = inner_treeify(right)?; }
 
 			let k = match this {
 				Token::PreOperator(_, k) => k,
@@ -309,7 +318,7 @@ fn treeify_unaryright(
 		if left_val.is_none() || this_val > left_val.unwrap() {
 			let this = g_inner.remove(i).unwrap();
 			let mut left = g_inner.remove(i-1).unwrap();
-			if let Token::PreGroup(_, _) = left { treeify(&mut left)?; }
+			if let Token::PreGroup(_, _) = left { left = inner_treeify(left)?; }
 
 			let k = match this {
 				Token::PreOperator(_, k) => k,
@@ -332,9 +341,9 @@ fn treeify_unaryright(
 	};
 }
 
-pub fn treeify(
+fn inner_treeify(
-	g: &mut Token,
+	mut g: Token,
-) -> Result<(), (LineLocation, ParserError)> {
+) -> Result<Token, (LineLocation, ParserError)> {
 
 	let g_inner: &mut VecDeque<Token> = match g {
 		Token::PreGroup(_, ref mut x) => x,
@@ -368,19 +377,28 @@ pub fn treeify(
 		};
 	}
 
-	*g = g_inner.pop_front().unwrap();
+	g = g_inner.pop_front().unwrap();
 
 	// Catch the edge case where the entire group we're given
 	// consists of one operator. This is always a syntax error.
 	match g {
 		Token::PreOperator(l, _) => {
-			return Err((*l, ParserError::Syntax));
+			return Err((l, ParserError::Syntax));
 		},
 		Token::PreGroup(_,_) => {
-			treeify(g)?;
+			g = treeify(g)?;
 		}
 		_ => {}
 	};
 
-	return Ok(());
+	return Ok(g);
+}
+
+pub fn treeify(
+	mut g: Token,
+) -> Result<Token, (LineLocation, ParserError)> {
+	let mut v: VecDeque<Token> = VecDeque::new();
+	v.push_back(inner_treeify(g)?);
+	g = Token::Root(v);
+	return Ok(g);
 }