Added CtoF and FtoC

README.md

@@ -75,6 +75,10 @@ Daisy instead provides four functions (`fromCelsius`, `toCelsius`, `fromFahrenhe
  - "from" functions take a scalar and return a value in Kelvin: `fromCelsius(0) = 273.15K`
  - "to" functions take a value in Kelvin and return a scalar: `toCelsius(273.15 K) = 0`
 
+Functions `FtoC` and `CtoF` are also provided:
+ - `FtoC(x) = toCelsius(fromFahrenheit(x))`
+ - `CtoF(x) = toFahrenheit(fromCelsius(x))`
+
 
 ## Multiplication Order
 

src/command/mod.rs

@@ -152,6 +152,9 @@ pub fn do_command(
 					"  Fahrenheit to Kelvin     [c]fromF, fromFahrenheit[n]\n",
 					"  Kelvin to Fahrenheit     [c]toF,   toFahrenheit[n]\n",
 					"\n",
+					"  Celsius to Fahrenheit    [c]CtoF[n]\n",
+					"  Fahrenheit to Celsius    [c]FtoC[n]\n",
+					"\n",
 					"  convert to base unit     [c]tobase[n]\n",
 					"  remove units             [c]nounit[n]\n",
 					"\n\n"

src/evaluate/function.rs

@@ -1,3 +1,5 @@
+use std::collections::VecDeque;
+
 use crate::parser::Expression;
 use crate::parser::Function;
 use crate::parser::Operator;
@@ -9,6 +11,7 @@ use crate::quantity::Quantity;
 use crate::quantity::Scalar;
 use crate::errors::DaisyError;
 use crate::context::Context;
+use super::evaluate;
 
 // If unitless, do nothing
 // If compatible with radians, convert to radians and return unitless
@@ -151,6 +154,33 @@ pub fn eval_function(context: &mut Context, g: &Expression) -> Result<Option<Exp
 		},
 
 
+		Function::CtoF => {
+			return Ok(evaluate(context,
+				&Expression::Operator(
+					*l + *loc,
+					Operator::Function(Function::ToFahrenheit),
+					VecDeque::from(vec![Expression::Operator(
+						*l + *loc,
+						Operator::Function(Function::FromCelsius),
+						VecDeque::from(vec![Expression::Quantity(*l, q.clone())])
+					)])
+				)
+			).ok());
+		},
+
+		Function::FtoC => {
+			return Ok(evaluate(context,
+				&Expression::Operator(
+					*l + *loc,
+					Operator::Function(Function::ToCelsius),
+					VecDeque::from(vec![Expression::Operator(
+						*l + *loc,
+						Operator::Function(Function::FromFahrenheit),
+						VecDeque::from(vec![Expression::Quantity(*l, q.clone())])
+					)])
+				)
+			).ok());
+		},
 
 		Function::ToCelsius => {
 			let mut k = Quantity::new_rational(1f64).unwrap();

src/parser/expression/function.rs

@@ -37,7 +37,9 @@ pub enum Function {
 	FromCelsius,
 	ToCelsius,
 	FromFahrenheit,
-	ToFahrenheit
+	ToFahrenheit,
+	CtoF,
+	FtoC,
 }
 
 
@@ -74,6 +76,8 @@ impl ToString for Function {
 			Function::ToCelsius => {String::from("tocelsius") },
 			Function::FromFahrenheit => { String::from("fromfahrenheit") },
 			Function::ToFahrenheit => { String::from("tofahrenheit") },
+			Function::FtoC => { String::from("FtoC") },
+			Function::CtoF => { String::from("CtoF") },
 		}
 	}
 
@@ -126,6 +130,11 @@ impl Function {
 			"fromF"          => {Some(Function::FromFahrenheit)},
 			"fromfahrenheit" => {Some(Function::FromFahrenheit)},
 			"fromFahrenheit" => {Some(Function::FromFahrenheit)},
+
+			"FtoC" => {Some(Function::FtoC)},
+			"ftoc" => {Some(Function::FtoC)},
+			"ctof" => {Some(Function::CtoF)},
+			"CtoF" => {Some(Function::CtoF)},
 			_ => None
 		}
 	}

src/tests.rs

@@ -232,5 +232,11 @@ fn functions() {
 
 	good_expr("2", "nounit(2 mm)");
 	good_expr("2", "nounit(2 meter * second)");
+
+	good_expr("37.778", "FtoC(100)");
+	good_expr("73.399", "CtoF(23)");
+	good_expr("-17.778", "FtoC(0)");
+	good_expr("31.999", "CtoF(0)");
+
 	//good_expr("5000 m²·g/(s²·A²)", "tobase(5H)");
 }