Feature/#10 merge recursive (#140)

pkg/stdlib/objects/merge_recursive.go

@@ -0,0 +1,66 @@
+package objects
+
+import (
+	"context"
+
+	"github.com/MontFerret/ferret/pkg/runtime/core"
+	"github.com/MontFerret/ferret/pkg/runtime/values"
+)
+
+// MergeRecursive recursively merge the given objects into a single object.
+// @params objs (Objects) - objects to merge.
+// @returns (Object) - Object created by merging.
+func MergeRecursive(_ context.Context, args ...core.Value) (core.Value, error) {
+	err := core.ValidateArgs(args, 1, core.MaxArgs)
+	if err != nil {
+		return values.None, err
+	}
+
+	for _, arg := range args {
+		if err = core.ValidateType(arg, core.ObjectType); err != nil {
+			return values.None, err
+		}
+	}
+
+	merged := values.NewObject()
+
+	for _, arg := range args {
+		merged = merge(merged, arg).(*values.Object)
+	}
+
+	return merged.Clone(), nil
+}
+
+func merge(src, dst core.Value) core.Value {
+	if src.Type() != dst.Type() {
+		return dst
+	}
+
+	if src.Type() != core.ObjectType {
+		return dst
+	}
+
+	srcObj := src.(*values.Object)
+	dstObj := dst.(*values.Object)
+
+	if dstObj.Length() == 0 {
+		return src
+	}
+
+	keyObj := values.NewString("")
+	exists := values.NewBoolean(false)
+	var srcVal core.Value
+
+	dstObj.ForEach(func(val core.Value, key string) bool {
+		keyObj = values.NewString(key)
+
+		if srcVal, exists = srcObj.Get(keyObj); exists {
+			val = merge(srcVal, val)
+		}
+
+		srcObj.Set(keyObj, val)
+		return true
+	})
+
+	return src
+}