feat(math): adding math:negate

Author: SuperFola

Math.ark

@@ -216,6 +216,11 @@
 # @author https://github.com/SuperFola
 (let decrement (fun (_x) (- _x 1)))
 
+# @brief Multiply a number by -1, turning positive numbers negative and negative numbers positive
+# #param _x number
+# @author https://github.com/SuperFola
+(let negate (fun (_x) (* -1 _x)))
+
 # @brief Get a number to a given power
 # @details Note that it's defined as exp(a * ln(x)), thus won't work for negative numbers
 # @param _x the number to pow

tests/math-tests.ark

@@ -35,6 +35,7 @@
     (test:eq (math:abs -1) 1)
     (test:eq (math:abs 0) 0)
     (test:eq (math:abs math:Inf) math:Inf)
+    (test:eq (math:abs (math:negate math:Inf)) math:Inf)
     (test:eq (math:abs 1) 1) })
 
   (test:case "even?" {
@@ -71,6 +72,12 @@
     (test:eq (math:decrement 1) 0)
     (test:eq (math:decrement 1.5) 0.5) })
 
+  (test:case "negate" {
+    (test:eq (math:negate 0) 0)
+    (test:eq (math:negate 1) -1)
+    (test:eq (math:negate -1) 1)
+    (test:eq (math:negate (math:negate 1)) 1) })
+
   (test:case "pow" {
     (test:eq (math:pow 2 2) 4)
     (test:eq (math:pow 4 0.5) 2) })