Sqrt func (#1166)

* Adding math square root function
* Adding info to readme on math square root function
* Handle overload error and test NaN
* adding version 2

Author: haribalan

ext/README.md

@@ -356,6 +356,23 @@ Examples:
     math.isFinite(0.0/0.0)  // returns false
     math.isFinite(1.2)      // returns true
 
+### Math.Sqrt
+
+Introduced at version: 2
+
+Returns the square root of the given input as double
+Throws error for negative or non-numeric inputs
+
+    math.sqrt(<double>) -> <double>
+    math.sqrt(<int>) -> <double>
+    math.sqrt(<uint>) -> <double>
+
+Examples:
+
+    math.sqrt(81) // returns 9.0
+    math.sqrt(985.25)   // returns 31.388692231439016
+    math.sqrt(-15)  // returns NaN
+
 ## Protos
 
 Protos configure extended macros and functions for proto manipulation.

ext/math.go

@@ -325,6 +325,23 @@ import (
 //
 //	math.isFinite(0.0/0.0)  // returns false
 //	math.isFinite(1.2)      // returns true
+//
+// # Math.Sqrt
+//
+// Introduced at version: 2
+//
+// Returns the square root of the given input as double
+// Throws error for negative or non-numeric inputs
+//
+//	math.sqrt(<double>) -> <double>
+//	math.sqrt(<int>) -> <double>
+//	math.sqrt(<uint>) -> <double>
+//
+// Examples:
+//
+//	math.sqrt(81) // returns 9.0
+//	math.sqrt(985.25)   // returns 31.388692231439016
+//      math.sqrt(-15)  // returns NaN
 func Math(options ...MathOption) cel.EnvOption {
 	m := &mathLib{version: math.MaxUint32}
 	for _, o := range options {
@@ -357,6 +374,9 @@ const (
 	absFunc  = "math.abs"
 	signFunc = "math.sign"
 
+	// SquareRoot function
+	sqrtFunc = "math.sqrt"
+
 	// Bitwise functions
 	bitAndFunc        = "math.bitAnd"
 	bitOrFunc         = "math.bitOr"
@@ -548,6 +568,18 @@ func (lib *mathLib) CompileOptions() []cel.EnvOption {
 			),
 		)
 	}
+	if lib.version >= 2 {
+		opts = append(opts,
+			cel.Function(sqrtFunc,
+				cel.Overload("math_sqrt_double", []*cel.Type{cel.DoubleType}, cel.DoubleType,
+					cel.UnaryBinding(sqrt)),
+				cel.Overload("math_sqrt_int", []*cel.Type{cel.IntType}, cel.DoubleType,
+					cel.UnaryBinding(sqrt)),
+				cel.Overload("math_sqrt_uint", []*cel.Type{cel.UintType}, cel.DoubleType,
+					cel.UnaryBinding(sqrt)),
+			),
+		)
+	}
 	return opts
 }
 
@@ -691,6 +723,21 @@ func sign(val ref.Val) ref.Val {
 	}
 }
 
+
+func sqrt(val ref.Val) ref.Val {
+	switch v := val.(type) {
+	case types.Double:
+	  return types.Double(math.Sqrt(float64(v)))
+	case types.Int:
+	  return types.Double(math.Sqrt(float64(v)))
+	case types.Uint:
+	  return types.Double(math.Sqrt(float64(v)))
+	default:
+	  return types.NewErr("no such overload: sqrt")
+	}
+}
+
+
 func bitAndPairInt(first, second ref.Val) ref.Val {
 	l := first.(types.Int)
 	r := second.(types.Int)

ext/math_test.go

@@ -181,6 +181,15 @@ func TestMath(t *testing.T) {
 		{expr: "math.abs(1) == 1"},
 		{expr: "math.abs(-234.5) == 234.5"},
 		{expr: "math.abs(234.5) == 234.5"},
+
+		// Tests for Square root function
+		{expr: "math.sqrt(49.0) == 7.0"},
+		{expr: "math.sqrt(0) == 0.0"},
+		{expr: "math.sqrt(1) == 1.0"},
+		{expr: "math.sqrt(25u) == 5.0"},
+		{expr: "math.sqrt(82) == 9.055385138137417"},
+		{expr: "math.sqrt(985.25) == 31.388692231439016"},
+		{expr: "math.isNaN(math.sqrt(-15.34))"},
 	}
 
 	env := testMathEnv(t,
@@ -472,6 +481,10 @@ func TestMathRuntimeErrors(t *testing.T) {
 			expr: "math.trunc(dyn(1u))",
 			err:  "no such overload: math.trunc(uint)",
 		},
+		{
+			expr: "math.sqrt(dyn(''))",
+			err:  "no such overload: math.sqrt(string)",
+		},
 	}
 
 	env := testMathEnv(t,
@@ -599,6 +612,12 @@ func TestMathVersions(t *testing.T) {
 				"bitShiftRight": `math.bitShiftRight(4, 2) == 1`,
 			},
 		},
+		{
+			version: 2,
+			supportedFunctions: map[string]string{
+				"sqrt":          `math.sqrt(25) == 5.0`,
+			},
+		},
 	}
 	for _, lib := range versionCases {
 		env, err := cel.NewEnv(Math(MathVersion(lib.version)))