forked from asklyphe-public/asklyphe
354 lines
9.5 KiB
Rust
354 lines
9.5 KiB
Rust
use tracing::{debug, error};
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use once_cell::sync::Lazy;
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#[derive(Debug)]
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pub struct Calculation {
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pub equation: String,
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pub result: String,
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}
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pub fn calculate(query: &str) -> Option<Calculation> {
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debug!("Got query {}", query);
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let mut parser = Parser::new(Lexer::new(query));
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let tree = parser.parse()?;
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let res = tree.eval();
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debug!("Calculation: {}", query);
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debug!("Tree: {:?}", tree);
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debug!("Result: {}", res);
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Some(Calculation {equation: query.to_string(), result: res.to_string()})
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}
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// TODO: put into own crate with dependency astro-float = "0.9.2" so I can use more than f64
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#[derive(Debug, Copy, Clone)]
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enum Token {
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Op(Op),
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Atom(Atom),
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/* Number(f64),
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Func(Func),*/
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}
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#[derive(Debug, Copy, Clone)]
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enum Op {
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Add,
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Subtract,
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Multiply,
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Divide,
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Exponent,
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LParen,
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RParen,
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Func(Func), // A function is an Op that takes whatever the next thing is and binds it, either the next number or whatever is in parens
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}
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impl Op {
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fn bp_infix(&self) -> Option<(f64, f64)> {
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match self {
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// Op::LParen => Some(0.0),
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// Op::RParen => Some(0.0),
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Op::Add => Some((1.0, 1.1)),
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Op::Subtract => Some((1.0, 1.1)),
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Op::Multiply => Some((2.0, 2.1)),
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Op::Divide => Some((2.0, 2.1)),
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Op::Exponent => Some((3.1, 3.0)),
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_ => None,
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// Op::Func(_) => 0.0, // TODO: decide if this is a good LBP
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}
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}
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fn bp_prefix(&self) -> Option<f64> {
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match self {
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Op::Func(_) => Some(0.1),
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Op::Subtract => Some(5.0),
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Op::Add => Some(5.0),
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_ => None,
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}
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}
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fn apply_to(&self, args: &Vec<Expr>) -> f64 {
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match args.len() {
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1 => match self {
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Op::Subtract => Some(0.0 - args[0].eval()),
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Op::Add => Some(args[0].eval().abs()),
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Op::Func(f) => match f {
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Func::Sine => Some(args[0].eval().sin()),
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Func::Cosine => Some(args[0].eval().cos()),
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Func::Tangent => Some(args[0].eval().tan()),
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Func::ArcSine => Some(args[0].eval().asin()),
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Func::ArcCosine => Some(args[0].eval().acos()),
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Func::ArcTangent => Some(args[0].eval().atan()),
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Func::Log2 => Some(args[0].eval().log2()),
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Func::Log10 => Some(args[0].eval().log10()),
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// Func::LogN => Some(),
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Func::Square => Some(args[0].eval().powf(2.0)),
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Func::SquareRoot => Some(args[0].eval().sqrt()),
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_ => todo!("{:?}", self)
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}
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_ => None,
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}
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2 => match self {
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Op::LParen => Some(args[0].eval()),
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Op::RParen => Some(args[0].eval()),
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Op::Add => Some(args[0].eval() + args[1].eval()),
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Op::Subtract => Some(args[0].eval() - args[1].eval()),
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Op::Multiply => Some(args[0].eval() * args[1].eval()),
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Op::Divide => Some(args[0].eval() / args[1].eval()),
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Op::Exponent => Some(args[0].eval().powf(args[1].eval())),
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_ => None,
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}
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_ => None,
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}.unwrap_or_else(|| {
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error!("ERROR when evaluating maths expression, got invalid number of args ({}) for {:?}", args.len(), self);
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// None
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f64::NAN
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})
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}
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}
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#[derive(Debug, Copy, Clone)]
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enum Atom {
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Number(f64), // TODO: use the high precision floats library instead
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Const(Const),
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}
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impl Atom {
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fn get_val(&self) -> f64 {
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match self {
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Atom::Number(val) => *val,
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Atom::Const(c) => match c {
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Const::Pi => 3.141592653589793238462643383279,
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Const::E => 2.718281828459045235360287471352,
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}
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}
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}
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}
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#[derive(Debug, Copy, Clone)]
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enum Func {
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Sine,
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Cosine,
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Tangent,
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// sin-1, cos-1, tan-1
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ArcSine,
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ArcCosine,
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ArcTangent,
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Log2,
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Log10,
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LogN,
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Square,
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SquareRoot,
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}
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#[derive(Debug, Copy, Clone)]
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enum Const {
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Pi,
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E,
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}
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#[derive(Debug, Copy, Clone)]
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enum ParseErr {
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Eof,
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Invalid,
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}
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// this can probably be swapped out with a lexer generator like Logos if needed
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struct Lexer<'a> {
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data: &'a str,
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data_ptr: &'a str,
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idx: usize,
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next_tok: Result<Token, ParseErr>,
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}
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// TODO: refactor with iterator that returns Option(Token) where one token option is Eof (or a enum of Token(Token) and Eof, or just Option(Option(Token)))
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impl Lexer<'_> {
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fn new(data: &str) -> Lexer<'_> {
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let mut n: Lexer = Lexer {data, data_ptr: data, idx: 0, next_tok: Err(ParseErr::Eof)};
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n.next();
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debug!("New finished!");
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n
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}
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fn _next(&mut self) -> Result<Token, ParseErr> {
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match self.data.chars().nth(self.idx) {
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Some(val) => {
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debug!("lexing char '{}' at idx {}", val, self.idx);
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// debug!("current char '{}'", self.data.chars().nth(0).unwrap());
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self.idx += 1;
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// TODO: make more efficient
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self.data_ptr = &self.data[self.idx..];
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match val {
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'+' => Ok(Token::Op(Op::Add)),
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'-' => Ok(Token::Op(Op::Subtract)),
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'×' | '*' => Ok(Token::Op(Op::Multiply)),
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'÷' | '/' => Ok(Token::Op(Op::Divide)),
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'^' => Ok(Token::Op(Op::Exponent)),
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'(' => Ok(Token::Op(Op::LParen)),
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')' => Ok(Token::Op(Op::RParen)),
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_ if val.is_whitespace() => self._next(),
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// TODO: maybe parse '-' as part of number so I can do '1 + -1' and similar
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_ if val.is_digit(10) => {
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let start = self.idx - 1;
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self.data_ptr.chars().take_while(|c| c.is_digit(10)).for_each(|_| self.idx += 1);//.next().unwrap_or(' ').is_digit(10) {self.idx += 1;}
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match self.data[start..self.idx].parse() {
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Ok(val) => Ok(Token::Atom(Atom::Number(val))),
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Err(e) => Err(ParseErr::Invalid),
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}
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},
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_ => {
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let mut l: usize;
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l = matches(&self.data[self.idx - 1..], "sin");
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if l != 0 {
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self.idx += l;
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return Ok(Token::Op(Op::Func(Func::Sine)));
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}
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l = matches(&self.data[self.idx - 1..], "cos");
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if l != 0 {
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self.idx += l;
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return Ok(Token::Op(Op::Func(Func::Cosine)));
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}
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l = matches(&self.data[self.idx - 1..], "tan");
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if l != 0 {
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self.idx += l;
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return Ok(Token::Op(Op::Func(Func::Tangent)));
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}
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l = matches(&self.data[self.idx - 1..], "arcsin");
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if l != 0 {
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self.idx += l;
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return Ok(Token::Op(Op::Func(Func::ArcSine)));
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}
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l = matches(&self.data[self.idx - 1..], "arccos");
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if l != 0 {
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self.idx += l;
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return Ok(Token::Op(Op::Func(Func::ArcCosine)));
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}
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l = matches(&self.data[self.idx - 1..], "arctan");
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if l != 0 {
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self.idx += l;
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return Ok(Token::Op(Op::Func(Func::ArcTangent)));
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}
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l = matches(&self.data[self.idx - 1..], "sqrt");
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if l != 0 {
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self.idx += l;
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return Ok(Token::Op(Op::Func(Func::SquareRoot)));
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}
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debug!("got invalid char '{}'", val);
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Err(ParseErr::Invalid)
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}
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}
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}
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None => Err(ParseErr::Eof),
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}
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}
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fn next(&mut self) -> Result<Token, ParseErr> {
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let val = self.next_tok;
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self.next_tok = self._next();
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val
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}
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fn peek(&mut self) -> Result<Token, ParseErr> {
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self.next_tok
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}
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// TODO: replace with iterator so I can do parser.parse(lexer.iter()) and parse does lex_iter.next() & such
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fn lex_all(&mut self) -> Option<Vec<Token>> {
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let mut tokens: Vec<Token> = vec![];
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loop {
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match self.next() {
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Err(ParseErr::Eof) => return Some(tokens),
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Err(ParseErr::Invalid) => return None,
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Ok(tok) => tokens.push(tok),
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}
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// debug!("tokens: {:?}", tokens);
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}
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}
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}
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fn matches(s: &str, check: &str) -> usize {
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// debug!("s: \"{}\", check: \"{}\"c_len: {}, s_len: {}, s[c_len]: {:?}, s[c_len + 1]: {:?}", s, check, check.chars().count(), s.chars().count(), s.chars().nth(check.chars().count()), s.chars().nth(check.chars().count() + 1));
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match (s.chars().count(), check.chars().count()) {
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(s_len, c_len) if s_len < c_len => 0,
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(s_len, c_len) if s_len == c_len && s == check => c_len - 1,
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(s_len, c_len) if s_len > c_len && s.starts_with(check) && s.chars().nth(c_len).unwrap().is_whitespace() => c_len,
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(_, _) => 0,
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}
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}
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struct Parser<'a> {
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lex: Lexer<'a>,
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}
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impl Parser<'_> {
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fn new(lex: Lexer) -> Parser { Parser {lex} }
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fn parse(&mut self) -> Option<Expr> {
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self.parse_expr(0.0).ok()
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}
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fn parse_expr(&mut self, min_bp: f64) -> Result<Expr, ParseErr> {
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/*while let Ok(val) = self.lex.next() {debug!("token: {:?}", val)}
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match self.lex.next().err() {
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_ => return Err(ParseErr::Invalid),
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}*/
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let mut lhs: Expr = match self.lex.next() {
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Ok(val) => match val {
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Token::Atom(val) => Ok(Expr::Atom(val)),
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Token::Op(op) => match op {
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Op::LParen => self.parse_expr(0.0),
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// Op::Func(f) => Ok(Expr::Node(Op::Func(f), vec![self.parse_expr(op.get_lbp())?])),
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_ => match op.bp_prefix() {
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Some(bp) => Ok(Expr::Node(op, vec![self.parse_expr(bp)?])),
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None => {debug!("Got unexpected {:?} as prefix", op); Err(ParseErr::Invalid)}
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}
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},
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},
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Err(err) => Err(err),
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}.map_err(|err| { debug!("Unexpected error at start of expr: {:?}", err); err })?;
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debug!("lhs of expression is {:?}", lhs);
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loop {
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let op: Op = match self.lex.peek() {
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Err(ParseErr::Eof) => break,
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Err(e) => { debug!("In expr got err {:?}", e); Err(e) },
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Ok(tok) => match tok {
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Token::Op(op) => match op {
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Op::RParen => break,
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_ => Ok(op),
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}
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v => { debug!("Got unexpected token {:?}", v); Err(ParseErr::Invalid) },
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}
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}.map_err(|err| { debug!("Unexpected error inside expr at {:?}", err); err })?;
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if let Some((lbp, rbp)) = op.bp_infix() {
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if (lbp < min_bp) { break; }
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self.lex.next();
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let rhs: Expr = self.parse_expr(rbp)?;
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lhs = Expr::Node(op, vec![lhs, rhs]);
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} else {
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debug!("Got unexpected non-infix operator in expression: {:?}", op);
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return Err(ParseErr::Invalid);
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}
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}
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Ok(lhs)
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}
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}
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#[derive(Debug)]
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enum Expr {
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Atom(Atom),
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Node(Op, Vec<Expr>),
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}
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impl Expr {
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fn eval(&self) -> f64 {
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let res = match (self) {
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Expr::Atom(at) => at.get_val(),
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Expr::Node(op, exprs) => op.apply_to(exprs),
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};
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// debug!("{:?} evaluated to {}", self, res);
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res
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}
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}
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