2022-02-23 10:01:06 -05:00

230 lines
7.5 KiB
Rust

use meval::Expr;
use wasm_bindgen::prelude::*;
pub type DrawResult<T> = Result<T, Box<dyn std::error::Error>>;
/*
EXTREMELY Janky function that tries to put asterisks in the proper places to be parsed. This is so cursed. But it works, and I hopefully won't ever have to touch it again.
One limitation though, variables with multiple characters like `pi` cannot be multiplied (like `pipipipi` won't result in `pi*pi*pi*pi`). But that's such a niche use case (and that same thing could be done by using exponents) that it doesn't really matter.
In the future I may want to completely rewrite this or implement this natively into mevel-rs (which would probably be good to do)
*/
pub fn add_asterisks(function_in: String) -> String {
let function = function_in.replace("log10(", "log(").replace("pi", "π"); // pi -> π and log10 -> log
let valid_variables: Vec<char> = "xeπ".chars().collect();
let letters: Vec<char> = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
.chars()
.collect();
let numbers: Vec<char> = "0123456789".chars().collect();
let function_chars: Vec<char> = function.chars().collect();
let mut output_string: String = String::new();
let mut prev_chars: Vec<char> = Vec::new();
for c in function_chars {
let mut add_asterisk: bool = false;
let prev_chars_len = prev_chars.len();
let prev_prev_char = if prev_chars_len >= 2 {
match prev_chars.get(prev_chars_len - 2) {
Some(x) => *x,
None => panic!(),
}
} else {
' '
};
let prev_char = if prev_chars_len >= 1 {
match prev_chars.get(prev_chars_len - 1) {
Some(x) => *x,
None => panic!(),
}
} else {
' '
};
let c_letters_var = letters.contains(&c) | valid_variables.contains(&c);
let prev_letters_var = valid_variables.contains(&prev_char) | letters.contains(&prev_char);
if prev_char == ')' {
if (c == '(') | numbers.contains(&c) | c_letters_var {
add_asterisk = true;
}
} else if c == '(' {
if (valid_variables.contains(&prev_char)
| (')' == prev_char)
| numbers.contains(&prev_char))
&& !letters.contains(&prev_prev_char)
{
add_asterisk = true;
}
} else if numbers.contains(&prev_char) {
if (c == '(') | c_letters_var {
add_asterisk = true;
}
} else if letters.contains(&c) {
if numbers.contains(&prev_char) {
add_asterisk = true;
} else if valid_variables.contains(&prev_char) && valid_variables.contains(&c) {
add_asterisk = true;
}
} else if (numbers.contains(&c) | c_letters_var) && prev_letters_var {
add_asterisk = true;
}
if add_asterisk {
output_string += "*";
}
prev_chars.push(c);
output_string += &c.to_string();
}
output_string.replace('π', "pi") // π -> pi
}
pub struct Function {
function: Box<dyn Fn(f64) -> f64>,
func_str: String,
}
impl Function {
pub fn from_string(func_str: String) -> Self {
let expr: Expr = func_str.parse().unwrap();
let func = expr.bind("x").unwrap();
Self {
function: Box::new(func),
func_str,
}
}
#[inline]
pub fn run(&self, x: f32) -> f32 { (self.function)(x as f64) as f32 }
pub fn str_compare(&self, other_string: String) -> bool { self.func_str == other_string }
pub fn get_string(&self) -> String { self.func_str.clone() }
}
/// Result of screen to chart coordinates conversion.
#[wasm_bindgen]
pub struct Point {
pub x: f32,
pub y: f32,
}
#[wasm_bindgen]
impl Point {
#[inline]
pub fn new(x: f32, y: f32) -> Self { Self { x, y } }
}
#[wasm_bindgen]
pub struct ChartOutput {
pub(crate) convert: Box<dyn Fn((i32, i32)) -> Option<(f32, f32)>>,
pub(crate) area: f32,
}
#[wasm_bindgen]
impl ChartOutput {
pub fn get_area(&self) -> f32 { self.area }
pub fn coord(&self, x: i32, y: i32) -> Option<Point> {
(self.convert)((x, y)).map(|(x, y)| Point::new(x, y))
}
}
pub struct Cache<T> {
backing_data: Option<T>,
}
impl<T> Cache<T> {
#[allow(dead_code)]
#[inline]
pub fn new(backing_data: T) -> Self {
Self {
backing_data: Some(backing_data),
}
}
#[inline]
pub fn new_empty() -> Self { Self { backing_data: None } }
#[inline]
pub fn get(&self) -> &T {
match &self.backing_data {
Some(x) => x,
None => panic!("self.backing_data is None"),
}
}
#[inline]
pub fn set(&mut self, data: T) { self.backing_data = Some(data); }
#[inline]
pub fn invalidate(&mut self) { self.backing_data = None; }
#[inline]
pub fn is_valid(&self) -> bool {
match &self.backing_data {
Some(_) => true,
None => false,
}
}
}
// Tests to make sure my cursed function works as intended
#[test]
fn asterisk_test() {
assert_eq!(&add_asterisks("2x".to_string()), "2*x");
assert_eq!(&add_asterisks("x2".to_string()), "x*2");
assert_eq!(&add_asterisks("x(1+3)".to_string()), "x*(1+3)");
assert_eq!(&add_asterisks("(1+3)x".to_string()), "(1+3)*x");
assert_eq!(&add_asterisks("sin(x)".to_string()), "sin(x)");
assert_eq!(&add_asterisks("2sin(x)".to_string()), "2*sin(x)");
assert_eq!(&add_asterisks("max(x)".to_string()), "max(x)");
assert_eq!(&add_asterisks("2e^x".to_string()), "2*e^x");
assert_eq!(&add_asterisks("2max(x)".to_string()), "2*max(x)");
assert_eq!(&add_asterisks("cos(sin(x))".to_string()), "cos(sin(x))");
assert_eq!(&add_asterisks("x^(1+2x)".to_string()), "x^(1+2*x)");
assert_eq!(&add_asterisks("(x+2)x(1+3)".to_string()), "(x+2)*x*(1+3)");
assert_eq!(&add_asterisks("(x+2)(1+3)".to_string()), "(x+2)*(1+3)");
assert_eq!(&add_asterisks("xxx".to_string()), "x*x*x");
assert_eq!(&add_asterisks("eee".to_string()), "e*e*e");
assert_eq!(&add_asterisks("pi(x+2)".to_string()), "pi*(x+2)");
assert_eq!(&add_asterisks("(x)pi".to_string()), "(x)*pi");
assert_eq!(&add_asterisks("2e".to_string()), "2*e");
assert_eq!(&add_asterisks("2log10(x)".to_string()), "2*log(x)");
assert_eq!(&add_asterisks("2log(x)".to_string()), "2*log(x)");
assert_eq!(&add_asterisks("x!".to_string()), "x!");
assert_eq!(
&add_asterisks("pipipipipipi".to_string()),
"pi*pi*pi*pi*pi*pi"
);
assert_eq!(&add_asterisks("10pi".to_string()), "10*pi");
assert_eq!(&add_asterisks("pi10".to_string()), "pi*10");
// Need to fix these checks, maybe I need to rewrite the whole asterisk adding system... (or just implement these changes into meval-rs, idk)
// assert_eq!(&add_asterisks("emax(x)".to_string()), "e*max(x)");
// assert_eq!(&add_asterisks("pisin(x)".to_string()), "pi*sin(x)");
}
// Tests cache when initialized with value
#[test]
fn cache_test_full() {
let mut cache = Cache::new("data");
assert!(cache.is_valid());
cache.invalidate();
assert_eq!(cache.is_valid(), false);
cache.set("data2");
assert!(cache.is_valid());
}
// Tests cache when initialized without value
#[test]
fn cache_test_empty() {
let mut cache: Cache<&str> = Cache::new_empty();
assert_eq!(cache.is_valid(), false);
cache.invalidate();
assert_eq!(cache.is_valid(), false);
cache.set("data");
assert!(cache.is_valid());
}