refactor progress

parsing/src/parsing.rs

@@ -1,21 +1,31 @@
 use exmex::prelude::*;
+use std::collections::HashMap;
 
 #[derive(Clone, PartialEq)]
-pub(crate) struct FlatExWrapper {
+pub(crate) struct FlatExWrapper<'a> {
 	func: Option<FlatEx<f64>>,
+	func_str: Option<&'a str>,
 }
 
-impl FlatExWrapper {
-	const EMPTY: FlatExWrapper = FlatExWrapper { func: None };
+impl<'a> FlatExWrapper<'a> {
+	const EMPTY: FlatExWrapper<'a> = FlatExWrapper {
+		func: None,
+		func_str: None,
+	};
 
 	#[inline]
-	const fn new(f: FlatEx<f64>) -> Self { Self { func: Some(f) } }
+	const fn new(f: FlatEx<f64>) -> Self {
+		Self {
+			func: Some(f),
+			func_str: None,
+		}
+	}
 
 	#[inline]
 	const fn is_none(&self) -> bool { self.func.is_none() }
 
 	#[inline]
-	fn eval(&self, x: &[f64]) -> f64 {
+	fn eval(&'a self, x: &[f64]) -> f64 {
 		self.func
 			.as_ref()
 			.map(|f| f.eval(x).unwrap_or(f64::NAN))
@@ -23,7 +33,7 @@ impl FlatExWrapper {
 	}
 
 	#[inline]
-	fn partial(&self, x: usize) -> Self {
+	fn partial(&'a self, x: usize) -> Self {
 		self.func
 			.as_ref()
 			.map(|f| f.clone().partial(x).map(Self::new).unwrap_or(Self::EMPTY))
@@ -31,10 +41,17 @@ impl FlatExWrapper {
 	}
 
 	#[inline]
-	fn get_string(&self) -> &str { self.func.as_ref().map(|f| f.unparse()).unwrap_or("") }
+	fn get_string(&'a mut self) -> &'a str {
+		if let Some(func_str) = self.func_str {
+			return func_str;
+		}
+		let calculated = self.func.as_ref().map(|f| f.unparse()).unwrap_or("");
+		self.func_str = Some(calculated);
+		return calculated;
+	}
 
 	#[inline]
-	fn partial_iter(&self, n: usize) -> Self {
+	fn partial_iter(&'a self, n: usize) -> Self {
 		self.func
 			.as_ref()
 			.map(|f| {
@@ -47,45 +64,29 @@ impl FlatExWrapper {
 	}
 }
 
-impl const Default for FlatExWrapper {
-	fn default() -> FlatExWrapper { FlatExWrapper::EMPTY }
+impl<'a> const Default for FlatExWrapper<'a> {
+	fn default() -> FlatExWrapper<'a> { FlatExWrapper::EMPTY }
 }
-
 /// Function that includes f(x), f'(x), f'(x)'s string representation, and f''(x)
 #[derive(Clone, PartialEq)]
-pub struct BackingFunction {
+pub struct BackingFunction<'a> {
 	/// f(x)
-	function: FlatExWrapper,
-
-	/// f'(x)
-	derivative_1: FlatExWrapper,
-
-	/// Mathematical representation of f'(x)
-	derivative_1_str: String,
-
-	/// f''(x)
-	derivative_2: FlatExWrapper,
+	function: FlatExWrapper<'a>,
 
 	/// Temporary cache for nth derivative
-	nth_derivative: Option<(usize, FlatExWrapper, String)>,
+	nth_derivative: HashMap<usize, FlatExWrapper<'a>>,
 }
 
-impl BackingFunction {
-	/// Empty [`BackingFunction`] instance
-	pub const EMPTY: BackingFunction = BackingFunction {
-		function: FlatExWrapper::EMPTY,
-		derivative_1: FlatExWrapper::EMPTY,
-		derivative_1_str: String::new(),
-		derivative_2: FlatExWrapper::EMPTY,
-		nth_derivative: None,
-	};
-
+impl<'a> BackingFunction<'a> {
 	pub const fn is_none(&self) -> bool { self.function.is_none() }
 
 	/// Create new [`BackingFunction`] instance
 	pub fn new(func_str: &str) -> Result<Self, String> {
 		if func_str.is_empty() {
-			return Ok(Self::EMPTY);
+			return Ok(Self {
+				function: FlatExWrapper::EMPTY,
+				nth_derivative: HashMap::new(),
+			});
 		}
 
 		let function = FlatExWrapper::new({
@@ -93,10 +94,8 @@ impl BackingFunction {
 
 			match &parse_result {
 				Err(e) => return Err(e.to_string()),
-				Ok(_) => {
-					let var_names = unsafe { parse_result.as_ref().unwrap_unchecked() }
-						.var_names()
-						.to_vec();
+				Ok(ok_result) => {
+					let var_names = ok_result.var_names().to_vec();
 
 					if var_names != ["x"] {
 						let var_names_not_x: Vec<&String> = var_names
@@ -117,61 +116,25 @@ impl BackingFunction {
 			unsafe { parse_result.unwrap_unchecked() }
 		});
 
-		let derivative_1 = function.partial(0);
-
-		let derivative_1_str = prettyify_function_str(derivative_1.get_string());
-
-		let derivative_2 = derivative_1.partial(0);
-
 		Ok(Self {
 			function,
-			derivative_1,
-			derivative_1_str,
-			derivative_2,
-			nth_derivative: None,
+
+			nth_derivative: HashMap::new(),
 		})
 	}
 
-	/// Returns Mathematical representation of the function's derivative
-	pub fn get_derivative_str(&self) -> &str { &self.derivative_1_str }
+	pub fn get(&'a mut self, derivative: usize, x: f64) -> f64 {
+		match derivative {
+			0 => self.function.eval(&[x]),
 
-	/// Calculate f(x)
-	pub fn get(&self, x: f64) -> f64 { self.function.eval(&[x]) }
-
-	/// Calculate f'(x)
-	pub fn get_derivative_1(&self, x: f64) -> f64 { self.derivative_1.eval(&[x]) }
-
-	/// Calculate f''(x)
-	pub fn get_derivative_2(&self, x: f64) -> f64 { self.derivative_2.eval(&[x]) }
-
-	/// Get string relating to the nth derivative
-	pub fn get_nth_derivative_str(&self) -> &str {
-		self.nth_derivative
-			.as_ref()
-			.map(|a| a.2.as_str())
-			.unwrap_or("")
-	}
-
-	pub fn get_nth_derivative(&mut self, n: usize, x: f64) -> f64 {
-		match n {
-			0 => self.get(x),
-			1 => self.get_derivative_1(x),
-			2 => self.get_derivative_2(x),
-			_ => {
-				if let Some((curr_n, curr_n_func, _)) = &self.nth_derivative {
-					if curr_n == &n {
-						return curr_n_func.eval(&[x]);
-					}
+			_ => match self.nth_derivative.get(&derivative) {
+				Some(func) => func.eval(&[x]),
+				None => {
+					let new_func = self.function.partial_iter(derivative);
+					self.nth_derivative.insert(derivative, new_func.clone());
+					new_func.eval(&[x])
 				}
-				let new_func = self.function.partial_iter(n);
-
-				self.nth_derivative = Some((
-					n,
-					new_func.clone(),
-					prettyify_function_str(new_func.get_string()),
-				));
-				new_func.eval(&[x])
-			}
+			},
 		}
 	}
 }