Added support of closing iterators if the implement io.Closer

pkg/compiler/visitor.go

@@ -233,7 +233,7 @@ func (v *visitor) VisitForExpression(ctx *fql.ForExpressionContext) interface{}
 
 	if isForInLoop {
 		// pop the iterator
-		v.emitPop()
+		v.emitPopAndClose()
 	}
 
 	return nil
@@ -918,6 +918,10 @@ func (v *visitor) emitPop() {
 	v.emit(runtime.OpPop)
 }
 
+func (v *visitor) emitPopAndClose() {
+	v.emit(runtime.OpPopClose)
+}
+
 func (v *visitor) emit(op runtime.Opcode, args ...int) {
 	v.bytecode = append(v.bytecode, op)
 

pkg/runtime/opcodes.go

@@ -47,8 +47,9 @@ const (
 	OpCall3
 	OpCall4
 	OpCallN
-	OpPop
 	OpPush
+	OpPop
+	OpPopClose
 	OpJumpIfFalse
 	OpJumpIfTrue
 	OpJump

pkg/runtime/vm.go

@@ -7,6 +7,7 @@ import (
 	"github.com/MontFerret/ferret/pkg/runtime/operators"
 	"github.com/MontFerret/ferret/pkg/runtime/values"
 	"github.com/MontFerret/ferret/pkg/runtime/values/types"
+	"io"
 )
 
 type VM struct {
@@ -58,6 +59,13 @@ loop:
 		case OpPop:
 			stack.Pop()
 
+		case OpPopClose:
+			closable, ok := stack.Pop().(io.Closer)
+
+			if ok {
+				closable.Close()
+			}
+
 		case OpStoreGlobal:
 			vm.globals[program.Constants[arg].String()] = stack.Pop()