# ST-NMG-002 - Arguments Naming Convention

> **Rule ID**: `ST-NMG-002`

**Rule ID**: `ST-NMG-002`

**Scope**: Workflow

## Description

This rule analyzes all arguments in the project and determines whether they follow the specific convention.

Arguments in the project should follow a specific naming convention to make it easier to understand the project and maintain it. The argument name should be meaningful and include an indication of its type:

* **in** – the argument can only be used within the given project.
* **out** – the argument can be used to pass data outside of a given project.
* **io** – the argument can be used both within and outside of a given project.

## Recommendation

Make sure all arguments follow the naming convention. The default Regex expression for this rule is:

* InRegex: `^in_(dt_)?([A-Z]|[a-z])+([0-9])*$`
* OutRegex: `^out_(dt_)?([A-Z]|[a-z])+([0-9])*$`
* InOutRegex: `^io_(dt_)?([A-Z]|[a-z])+([0-9])*$`.

According to the above regex expression, the argument matches the expression if it starts with a prefix, followed by a lower or upper case letter, and a number.

For example, if the argument name in the workflow is `in_HelloWorld` then it is validated by the rule. Other examples of argument names that follow this regex rule are: `out_HelloWorld` and `io_Helloworld`.

## Modifying the Rule

In the **Project Settings** window, select the **Workflow Analyzer** tab. Find and select the rule, as in the image below:

  ![docs image](https://dev-assets.cms.uipath.com/assets/images/studio/standalone-docs-image-170327-dec8b041.webp)

In the **Regex** section, add or remove characters from the search pattern. For example, if we remove the `[A-Z]` part of the expression for In arguments, the search pattern becomes `^in_(dt_)?([a-z])+([0-9])*$`. Now the rule checks if In arguments start with a lower case letter after the prefix.

If we add `[a-z]|[A-Z])`, then the rule becomes `^in_(dt_)?([A-Z]|[a-z]|[a-z]|[A-Z])+([0-9])*$`, and recognizes `in_HelloWonderfulWorld` as a valid In argument name.

## Examples of Regex Expressions

The default regex expression for this rule can be changed to another naming convention. Check the list below:

### Camel case

The camel case convention specifies that each word in the middle of the argument name begins with a capital letter, with no intervening spaces or punctuation.

Example of Regex expression: `^in_(dt_)?([A-Z]|[a-z]|[0-9])+([A-Z]|[a-z]|[0-9])`.

Valid argument names: `in_Hello1World2`, `in_helloWorld`, `in_Hello1World`.

### Pascal case

The Pascal case naming convention specifies that the argument name must contain concatenated capitalized words.

Example of Regex expression: `^in_(dt_)?([A-Z]|[0-9])+([A-Z]|[a-z]|[0-9])`.

Valid names: `in_Hello1World2`, `in_HelloWorld`, `in_Hello1World`.

### Kebab case

The Kebab case naming convention is similar to snake case, except that it replaces spaces with hyphens rather than underscores.

Example of Regex expression: `^in_(dt_)?([a-z]|[A-Z]|[0-9])+‐([a-z]|[A-Z]|[0-9])`

Valid names: `in_Hello1‐World2`, `in_Hello‐World`.

## Reset to Default Values

The default values for ST-NMG-002 Regex are:

* InRegex: `^in_(dt_)?([A-Z]|[a-z])+([0-9])*$`
* OutRegex: `^out_(dt_)?([A-Z]|[a-z])+([0-9])*$`
* InOutRegex: `^io_(dt_)?([A-Z]|[a-z])+([0-9])*$`.

To reset these values to default right-click a rule in the **Project Settings** window, and then click **Reset to default**.

  ![docs image](https://dev-assets.cms.uipath.com/assets/images/studio/standalone-docs-image-171184-bd4c7302.webp)