Added unit checks to temp conversions

src/evaluate/evaluate.rs

@@ -63,7 +63,7 @@ pub fn evaluate(
 
 					context.get_variable(&s)
 				},
-				Expression::Operator(_, Operator::Function(_), _) => { eval_function(g)? },
+				Expression::Operator(_, Operator::Function(_), _) => { eval_function(context, g)? },
 				Expression::Operator(_, _, _) => { eval_operator(context, g)? },
 			};
 

src/evaluate/function.rs

@@ -3,11 +3,12 @@ use crate::parser::Function;
 use crate::parser::Operator;
 use crate::parser::LineLocation;
 use crate::quantity::FreeUnit;
+use crate::quantity::Unit;
 use crate::quantity::WholeUnit;
 use crate::quantity::Quantity;
 use crate::quantity::Scalar;
 use crate::errors::DaisyError;
-
+use crate::context::Context;
 
 // If unitless, do nothing
 // If compatible with radians, convert to radians and return unitless
@@ -26,7 +27,7 @@ fn to_radians(q: Quantity) -> Result<Quantity, ()> {
 
 
 
-pub fn eval_function(g: &Expression) -> Result<Option<Expression>, (LineLocation, DaisyError)> {
+pub fn eval_function(context: &mut Context, g: &Expression) -> Result<Option<Expression>, (LineLocation, DaisyError)> {
 
 	let Expression::Operator(loc, Operator::Function(f), args) = g else {unreachable!()};
 
@@ -154,17 +155,51 @@ pub fn eval_function(g: &Expression) -> Result<Option<Expression>, (LineLocation
 		Function::ToCelsius => {
 			let mut k = Quantity::new_rational(1f64).unwrap();
 			k.insert_unit(FreeUnit::from_whole(WholeUnit::Kelvin), Scalar::new_rational(1f64).unwrap());
-			let Some(q) = q.convert_to(k) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)) };
+
+			let q_s: String;
+			if q.unitless() {
+				q_s = String::from("scalar");
+			} else {
+				q_s = q.convert_to_base().unit().display(context);
+			}
+
+			let Some(q) = q.convert_to(k) else {
+				return Err((
+					*loc + *l,
+					DaisyError::IncompatibleUnits(
+						q_s,
+						Unit::from_free(FreeUnit::from_whole(WholeUnit::Kelvin)).display(context)
+					)
+				))
+			};
 
 			let mut r = q.without_unit();
 			r += Quantity::new_rational(-273.15f64).unwrap();
 
 			return Ok(Some(Expression::Quantity(*loc + *l, r)));
 		},
+
+
 		Function::ToFahrenheit => {
 			let mut k = Quantity::new_rational(1f64).unwrap();
 			k.insert_unit(FreeUnit::from_whole(WholeUnit::Kelvin), Scalar::new_rational(1f64).unwrap());
-			let Some(q) = q.convert_to(k) else { return Err((*loc + *l, DaisyError::IncompatibleUnit)) };
+
+			let q_s: String;
+			if q.unitless() {
+				q_s = String::from("scalar");
+			} else {
+				q_s = q.convert_to_base().unit().display(context);
+			}
+
+			let Some(q) = q.convert_to(k) else {
+				return Err((
+					*loc + *l,
+					DaisyError::IncompatibleUnits(
+						q_s,
+						Unit::from_free(FreeUnit::from_whole(WholeUnit::Kelvin)).display(context)
+					)
+				))
+			};
 
 			let mut r = q.without_unit();
 			r *= Quantity::new_rational_from_frac(9i64, 5i64).unwrap();
@@ -173,8 +208,18 @@ pub fn eval_function(g: &Expression) -> Result<Option<Expression>, (LineLocation
 
 			return Ok(Some(Expression::Quantity(*loc + *l, r)));
 		},
+
+
 		Function::FromCelsius => {
-			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
+			if !q.unitless() {
+				return Err((
+					*loc + *l,
+					DaisyError::IncompatibleUnits(
+						q.convert_to_base().unit().display(context),
+						"scalar".to_string()
+					)
+				));
+			}
 
 			let mut r = Quantity::new_rational(273.15f64).unwrap();
 			r += q.clone();
@@ -182,8 +227,18 @@ pub fn eval_function(g: &Expression) -> Result<Option<Expression>, (LineLocation
 
 			return Ok(Some(Expression::Quantity(*loc + *l, r)));
 		},
+
+
 		Function::FromFahrenheit => {
-			if !q.unitless() { return Err((*loc + *l, DaisyError::IncompatibleUnit));}
+			if !q.unitless() {
+				return Err((
+					*loc + *l,
+					DaisyError::IncompatibleUnits(
+						q.convert_to_base().unit().display(context),
+						"scalar".to_string()
+					)
+				));
+			}
 
 			let mut r = q.clone();
 			r += Quantity::new_rational(459.67).unwrap();