Refactoring

In general, refactoring is a technique for improving the design of existing software code without changing the way it functions.

In CODESYS, refactoring provides functions for renaming objects and variables and updating referenced pins. You can display all occurrences of renamed objects and variables and then rename them all at once or individually. In “Tools Options”, you can also configure where CODESYS will prompt you for refactoring.

Renaming global variables

Requirement: A project is open that includes at least a function block “FB” and a global variable list. The global variable list “GVL” is open in the editor and contains a variable declaration (example: ‎iGlobal‎). “FB” uses ‎iGlobal‎.

Renaming global variables throughout the project

Select the global variable name ‎iGlobal‎.
Right-click the variable and click “Refactoring Rename iGlobal”.
In the “Rename” dialog, type a name in the “New name” input field, for example ‎iGlobalOK‎, and click “OK”.

The “Refactoring” dialog opens. In the device tree view on the left, the “GVL” and “FB” objects are highlighted in red and yellow. In the view on the right, “FB” in is open in its editor and ‎iGlobal‎ has already been renamed as ‎iGlobalOK‎.
Click “OK”.
No global variable ‎iGlobal‎ is in your project. Now ‎iGlobalOK‎ is everywhere.

Renaming global variables throughout the project (except for a POU)

Select the global variable name ‎iGlobal‎.
Right-click the variable and click “Refactoring Rename iGlobal”.
In the “Rename” dialog, type a name in the “New name” input field, for example ‎iGlobalTest‎, and click “OK”.

The “Refactoring” dialog opens. In the device tree view on the left, the “GVL” and “FB” objects are highlighted in red and yellow. In the window on the right, the function block “FB ” is open in its editor. ‎iGlobalTest‎ is listed instead of ‎iGlobal‎.
Right-click in the view on the right.
Click “Reject this Object” and click “OK”.

The global variable ‎iGlobal‎ is available in “FB” in your project. The variable ‎iGlobalTest‎ is now specified in the objects where the previous variable occurred.

The error message in the message view reports that the ‎iGlobal‎ identifier is not defined.

Adding and removing input variables

In the declaration part of blocks, you can add and delete input and output variables by using the refactoring commands. CODESYS performs updates at the occurrence locations and calling locations of the blocks. You can accept or reject these updates individually. The “Refactoring” dialog also opens for this purpose.

Requirement: The ‎FCT‎ (function type) POU is open in the editor. The function already contains the input variables ‎input1‎, ‎input2‎, and ‎inputx‎. They are called in the ‎PLC_PRG‎ and ‎POU‎ programs.

Set the focus in the declaration part of the FCT function.
Click “Refactoring Add Variable”.

The default dialog opens for declaring variables.
Declare the variable ‎input_3‎ with the scope of ‎VAR_INPUT‎ and data type ‎INT‎. Click “OK” to close the dialog.

The “Refactoring” dialog opens (see figure below). The affected locations are marked in yellow. (1)+(2)
In the upper right corner, select “Add inputs with placeholder text” from the drop-down list. (3).
In the left side of the window, click one of the highlighted objects (for example, ‎PLC_PRG‎). Right-click and choose the “Accept Whole Project” command to add the new variable at the new location of use in ‎FCT‎ for the entire project.

You see the change in the implementation part of ‎PLC_PRG‎ in the view on the right: The placeholder ‎_REFACTOR_‎ appears at the location where the new variable was added.
Click “OK” to close the “Refactoring” dialog.
Click “Edit Find”. Search the project for "_REFACTOR_" to check and edit the affected locations.
Note: As an alternative, you can insert the new variable with another initialization value without working with a placeholder first. In this case, in Step 4 you select "Add inputs with the following value" and type the value in the field on the right side of the drop-down list.

Example of a new variable with placeholder text in a CFC block:

Please note that you can also remove variables with refactoring.

Reordering variables in the declaration

In the declaration part of function blocks, you can change the order of declarations by refactoring This is possible for declarations with scope ‎VAR_INPUT‎, ‎VAR_OUTPUT‎, or ‎VAR_IN_OUT‎.

Requirement: The declaration part of a POU is open and includes declarations, for example:

VAR_INPUT
	invar2 : INT;
	invar1 : INT;
	in : DUT;
	bvar : BOOL;
	invar3 : INT;
END_VAR

Right-click in this declaration block to access the context menu.
Click “Refactoring Reorder Variables”.

The “Reorder” dialog opens with a list of ‎VAR_INPUT‎ variables.
Drag the “invar1 : INT;” entry to the position before the “invar2.” entry.

The ‎invar1‎ declaration is now at the top position.
Click “OK” to close the dialog.

The “Refactoring” dialog opens. The affected locations are marked in yellow (see figure above).
Click “OK” to accept the new order for the function block.

Changing a variable declaration and applying refactoring automatically

Refactoring helps you in the declaration when renaming variables (by means of "Auto declare").

Requirement: Function block ‎fb_A‎.

Click “Tools Options”.

The “Options” dialog opens.
Select the “Refactoring” category.
In “Auto-Declare”, activate the options “On renaming variables” and “On adding or removing variables, or for changing the namespace”.
Double-click the function block ‎fb_A‎.
Select a variable in the declaration of ‎fb_A‎, for example ‎iA‎. As an alternative, you can set the cursor before or in the variable.
Specify “Edit Declare variable” ([Shift]+[F2]).

The “Declare Variable” dialog opens. The dialog includes the settings of ‎iA‎.
Change the name of ‎iA‎ to ‎iCounter_A‎.
The option “Changes by means of refactoring” appears and is activated.
Click “OK”.

The dialog “Refactoring” “Renaming from iA to iCounterA” opens. All locations affected by the variable renaming are marked there.
Click “OK” to close the dialog.

The changes are applied.