Merge pull request #244 from fa993/main

Feature Request: Percentages

core/src/ast.rs

@@ -425,7 +425,16 @@ pub(crate) fn evaluate<I: Interrupt>(
 					return Ok(val);
 				}
 			}
-			eval!(*a)?.apply(*b, ApplyMulHandling::Both, scope, attrs, context, int)?
+			match (*a, *b) {
+				(a, Expr::Of(x, expr)) if x.as_str() == "%" => eval!(a)?
+					.handle_num(
+						|x| x.div(Number::from(100), int),
+						Expr::UnaryDiv,
+						scope.clone(),
+					)?
+					.apply(*expr, ApplyMulHandling::Both, scope, attrs, context, int)?,
+				(a, b) => eval!(a)?.apply(b, ApplyMulHandling::Both, scope, attrs, context, int)?,
+			}
 		}
 		Expr::ApplyFunctionCall(a, b) => {
 			eval!(*a)?.apply(*b, ApplyMulHandling::OnlyApply, scope, attrs, context, int)?

core/tests/integration_tests.rs

@@ -2148,6 +2148,27 @@ fn five_percent_times_100() {
 	test_eval("5% * 100", "500%");
 }
 
+#[test]
+fn five_percent_of_100() {
+	// Continuing the discussion in the previous test
+	// We handle the overloading in the evaluate function
+	// If we encounter an Of with a percent in the LHS
+	// Then we divide the LHS with 100 and multiply it with RHS
+	// Discarding the percent in the process
+
+	test_eval("5% of 100", "5");
+}
+
+#[test]
+fn five_percent_of_200() {
+	test_eval("2 + 5% of 200", "12");
+}
+
+#[test]
+fn five_percent_of_200_2() {
+	test_eval("(2 + 5)% of 200", "14");
+}
+
 #[test]
 fn units_1() {
 	test_eval("0m + 1kph * 1 hr", "1000 m");