Merge 81e6c48 into b9431fe

docs/types/array.md

@@ -350,6 +350,15 @@ a.shift() # 1
 a # [2, 3]
 ```
 
+### shuffle()
+
+Shuffles elements in the array:
+
+``` py
+a = [1, 2, 3, 4]
+a.shuffle() # [3, 1, 2, 4]
+```
+
 ### some(f)
 
 Returns true when at least one of the elements in the array

evaluator/builtin_functions_test.go

@@ -385,6 +385,16 @@ func TestReverse(t *testing.T) {
 	testBuiltinFunction(tests, t)
 }
 
+func TestShuffle(t *testing.T) {
+	tests := []Tests{
+		{`(1..1000).shuffle().str() != (1..1000).str();`, true},
+		{`(1..1000).shuffle().len() == (1..1000).len();`, true},
+		{`(1..1000).shuffle().sort().str() == (1..1000).str();`, true},
+	}
+
+	testBuiltinFunction(tests, t)
+}
+
 func TestPush(t *testing.T) {
 	tests := []Tests{
 		{`[1, 2].push("a");`, []interface{}{1, 2, "a"}},

evaluator/functions.go

@@ -9,6 +9,7 @@ import (
 	"io/ioutil"
 	"math"
 	"math/big"
+	mrand "math/rand"
 	"os"
 	"os/exec"
 	"os/user"
@@ -367,6 +368,11 @@ func getFns() map[string]*object.Builtin {
 			Types: []string{object.ARRAY_OBJ, object.STRING_OBJ},
 			Fn:    reverseFn,
 		},
+		// shuffle([1,2,3])
+		"shuffle": &object.Builtin{
+			Types: []string{object.ARRAY_OBJ},
+			Fn:    shuffleFn,
+		},
 		// push([1,2,3], 4)
 		"push": &object.Builtin{
 			Types: []string{object.ARRAY_OBJ},
@@ -1948,6 +1954,22 @@ func reverseFn(tok token.Token, env *object.Environment, args ...object.Object)
 	}
 }
 
+// shuffle([1,2,3])
+func shuffleFn(tok token.Token, env *object.Environment, args ...object.Object) object.Object {
+	err := validateArgs(tok, "shuffle", args, 1, [][]string{{object.ARRAY_OBJ}})
+
+	if err != nil {
+		return err
+	}
+
+	array := args[0].(*object.Array)
+
+	mrand.Seed(time.Now().UnixNano())
+	mrand.Shuffle(len(array.Elements), func(i, j int) { array.Elements[i], array.Elements[j] = array.Elements[j], array.Elements[i] })
+
+	return array
+}
+
 // push([1,2,3], 4)
 func pushFn(tok token.Token, env *object.Environment, args ...object.Object) object.Object {
 	err := validateArgs(tok, "push", args, 2, [][]string{{object.ARRAY_OBJ}, {object.NULL_OBJ,