From b7b466b77462c81d6d8a8bb2c9e01c70f11dbbf1 Mon Sep 17 00:00:00 2001
From: Book-reader <thevoid@outlook.co.nz>
Date: Fri, 5 Sep 2025 20:37:13 +1200
Subject: [PATCH] *Mostly* works, apart from `4 sqrt 4` being
 `1.4142135623730951` for some reason (messed up unary operators or something)

---
 asklyphe-frontend/src/math.rs | 62 ++++++++++++++++++++++++++++++++---
 1 file changed, 58 insertions(+), 4 deletions(-)

diff --git a/asklyphe-frontend/src/math.rs b/asklyphe-frontend/src/math.rs
index fc7b224..3f100c4 100644
--- a/asklyphe-frontend/src/math.rs
+++ b/asklyphe-frontend/src/math.rs
@@ -10,9 +10,11 @@ pub struct Calculation {
 pub fn calculate(query: &str) -> Option<Calculation> {
 	debug!("Got query {}", query);
 	let mut parser = Parser::new(Lexer::new(query));
-	debug!("Parse tree: {:?}", parser.parse());
-	// debug!("final token was: {:?}", lexer.next());
-	// debug!("Tokens: {:?}", lexer.lex_all());
+	let res = parser.parse()?;
+
+	debug!("Calculation: {}", query);
+	debug!("Tree: {:?}", res);
+	debug!("Result: {}", res.eval());
 	None
 }
 
@@ -43,7 +45,7 @@ impl Op {
 				BinOp::Divide => 2.0,
 				BinOp::Exponent => 3.0,
 			},
-			Op::Func(_) => 2.9, // TODO: decide if this is a good LBP
+			Op::Func(_) => 0.9, // TODO: decide if this is a good LBP
 		}
 	}
 
@@ -62,6 +64,26 @@ impl Op {
 		}
 
 	}
+
+	fn apply_to(&self, args: &Vec<Expr>) -> f64 {
+		match (self) {
+			Op::BinOp(op) => match op {
+				BinOp::LParen => args[0].eval(),
+				BinOp::RParen => args[0].eval(),
+				BinOp::Add => args[0].eval() + args[1].eval(),
+				BinOp::Subtract => args[0].eval() - args[1].eval(),
+				BinOp::Multiply => args[0].eval() * args[1].eval(),
+				BinOp::Divide => args[0].eval() / args[1].eval(),
+				BinOp::Exponent => args[0].eval().powf(args[1].eval()),
+			},
+			Op::Func(f) => match f {
+				Func::Sine => args[0].eval().sin(),
+				Func::ArcSine => args[0].eval().asin(),
+				Func::SquareRoot => args[0].eval().sqrt(),
+				_ => todo!("{:?}", f),
+			},
+		}
+	}
 }
 
 #[derive(Debug, Copy, Clone)]
@@ -185,6 +207,27 @@ impl Lexer<'_> {
 							self.idx += l;
 							return Ok(Token::Op(Op::Func(Func::Tangent)));
 						}
+						l = matches(&self.data[self.idx - 1..], "arcsin");
+						if l != 0 {
+							self.idx += l;
+							return Ok(Token::Op(Op::Func(Func::ArcSine)));
+						}
+						l = matches(&self.data[self.idx - 1..], "arccos");
+						if l != 0 {
+							self.idx += l;
+							return Ok(Token::Op(Op::Func(Func::ArcCosine)));
+						}
+						l = matches(&self.data[self.idx - 1..], "arctan");
+						if l != 0 {
+							self.idx += l;
+							return Ok(Token::Op(Op::Func(Func::ArcTangent)));
+						}
+						l = matches(&self.data[self.idx - 1..], "sqrt");
+						if l != 0 {
+							self.idx += l;
+							return Ok(Token::Op(Op::Func(Func::SquareRoot)));
+						}
+
 						debug!("got invalid char '{}'", val);
 						Err(ParseErr::Invalid)
 					}
@@ -289,3 +332,14 @@ enum Expr {
 	Atom(Atom),
 	Node(Op, Vec<Expr>),
 }
+
+impl Expr {
+	fn eval(&self) -> f64 {
+		let res = match (self) {
+			Expr::Atom(at) => at.get_val(),
+			Expr::Node(op, exprs) => op.apply_to(exprs),
+		};
+		// debug!("{:?} evaluated to {}", self, res);
+		res
+	}
+}