some improvments

internal/pdf/ps/exec.go

@@ -37,24 +37,24 @@ func PSObjectArrayToFloat64Array(objects []PSObject) ([]float64, error) {
 	return vals, nil
 }
 
-func (this *PSExecutor) Execute(objects []PSObject) ([]PSObject, error) {
+func (pE *PSExecutor) Execute(objects []PSObject) ([]PSObject, error) {
 	// Add the arguments on stack
 	// [obj1 obj2 ...]
 	for _, obj := range objects {
-		err := this.Stack.Push(obj)
+		err := pE.Stack.Push(obj)
 		if err != nil {
 			return nil, err
 		}
 	}
 
-	err := this.program.Exec(this.Stack)
+	err := pE.program.Exec(pE.Stack)
 	if err != nil {
 		common.Log.Debug("Exec failed: %v", err)
 		return nil, err
 	}
 
-	result := []PSObject(*this.Stack)
-	this.Stack.Empty()
+	result := []PSObject(*pE.Stack)
+	pE.Stack.Empty()
 
 	return result, nil
 }