Merge pull request #131 from Flipez/fix-random-prediction

Flipez · web-flow · commit 4878cbd554e9 · 2022-10-27T18:41:51.000+02:00
[stdlib/math] Seed rand on each call
diff --git a/stdlib/math.go b/stdlib/math.go
@@ -3,6 +3,7 @@ package stdlib
 import (
 	"math"
 	"math/rand"
+	"time"
 
 	"github.com/flipez/rocket-lang/object"
 )
@@ -11,6 +12,10 @@ var mathFunctions = map[string]*object.BuiltinFunction{}
 var mathProperties = map[string]*object.BuiltinProperty{}
 
 func init() {
+	// Randomize seed each runtime to avoid predictable results
+	randSource := rand.NewSource(time.Now().UnixNano())
+	randomizedRand := rand.New(randSource)
+
 	mathFunctions["abs"] = object.NewBuiltinFunction("abs",
 		object.MethodLayout{
 			ReturnPattern: object.Args(object.Arg(object.FLOAT_OBJ)),
@@ -215,7 +220,7 @@ func init() {
 			ReturnPattern: object.Args(object.Arg(object.FLOAT_OBJ)),
 		},
 		func(_ object.Environment, args ...object.Object) object.Object {
-			return object.NewFloat(rand.Float64())
+			return object.NewFloat(randomizedRand.Float64())
 		},
 	)
 	mathFunctions["remainder"] = object.NewBuiltinFunction("remainder",
