Integrate into the editor

Cargo.toml

@@ -35,6 +35,7 @@ graph-craft = { path = "node-graph/graph-craft", features = ["serde"] }
 wgpu-executor = { path = "node-graph/wgpu-executor" }
 bezier-rs = { path = "libraries/bezier-rs", features = ["dyn-any"] }
 path-bool = { path = "libraries/path-bool", default-features = false }
+math-parser = { path = "libraries/math-parser" }
 node-macro = { path = "node-graph/node-macro" }
 
 # Workspace dependencies

frontend/wasm/Cargo.toml

@@ -38,6 +38,7 @@ wasm-bindgen-futures = { workspace = true }
 bezier-rs = { workspace = true }
 glam = { workspace = true }
 meval = { workspace = true }
+math-parser = { workspace = true }
 wgpu = { workspace = true, features = [
 	"fragile-send-sync-non-atomic-wasm",
 ] } # We don't have wgpu on multiple threads (yet) https://github.com/gfx-rs/wgpu/blob/trunk/CHANGELOG.md#wgpu-types-now-send-sync-on-wasm

frontend/wasm/src/editor_api.rs

@@ -916,18 +916,12 @@ impl EditorHandle {
 
 #[wasm_bindgen(js_name = evaluateMathExpression)]
 pub fn evaluate_math_expression(expression: &str) -> Option<f64> {
-	// TODO: Rewrite our own purpose-built math expression parser that supports unit conversions.
-
-	let mut context = meval::Context::new();
-	context.var("tau", std::f64::consts::TAU);
-	context.func("log", f64::log10);
-	context.func("log10", f64::log10);
-	context.func("log2", f64::log2);
-
-	// Insert asterisks where implicit multiplication is used in the expression string
-	let expression = implicit_multiplication_preprocess(expression);
-
-	meval::eval_str_with_context(expression, &context).ok()
+	let value = math_parser::evaluate(expression).inspect_err(|err| error!("Math parser error on \"{expression}\": {err}")).ok()?;
+	let Some(real) = value.as_real() else {
+		error!("{value} was not a real; skipping.");
+		return None;
+	};
+	Some(real)
 }
 
 // Modified from this public domain snippet: <https://gist.github.com/Titaniumtown/c181be5d06505e003d8c4d1e372684ff>

libraries/math-parser/Cargo.toml

@@ -1,7 +1,11 @@
 [package]
 name = "math-parser"
-version = "0.1.0"
+version = "0.0.0"
+rust-version = "1.79"
 edition = "2021"
+authors = ["Graphite Authors <contact@graphite.rs>"]
+description = "Parser for Graphite style mathematics expressions"
+license = "MIT OR Apache-2.0"
 
 [dependencies]
 pest = "2.7"

libraries/math-parser/src/value.rs

@@ -7,10 +7,28 @@ impl Value {
 	pub fn from_f64(x: f64) -> Self {
 		Self::Complex(x, 0.0)
 	}
+	/// Attempt to convert to a real number
+	pub fn as_real(&self) -> Option<f64> {
+		match self {
+			Self::Complex(real, imaginary) if imaginary.abs() < f64::EPSILON => Some(*real),
+			_ => None,
+		}
+	}
 }
 
 impl From<f64> for Value {
 	fn from(x: f64) -> Self {
 		Self::from_f64(x)
 	}
 }
+
+impl core::fmt::Display for Value {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		if let Some(real) = self.as_real() {
+			return real.fmt(f);
+		}
+		match self {
+			Value::Complex(real, imaginary) => write!(f, "{real}{imaginary:+}i"),
+		}
+	}
+}