Understanding Naming Rules for Variables and Devices in VEXcode EXP

In VEXcode EXP, you are required to give a name to a new variable when you create one. You also have the option to change a device’s name in the Robot Configuration. 

Valid Name Rules

Variable names must be unique, but there are other specifications that the name must follow. 

Variable names are used in the following places:

  1. Device (created using Robot Configuration)
  2. Numeric (created using “Make variable”)
  3. Boolean (created using “Make a boolean”)
  4. List (created using “Make a List”)
  5. 2D List (created using “Make a 2D List”)

Here is an overview of the criteria when choosing a valid name:

The name cannot use special characters.

The name has to begin with a letter. It cannot start with a number.

The name cannot use spaces.

The name cannot be a reserved word in VEXcode. A reserved word is a word or name that VEXcode is already using.

Examples: vex, Brain, time, for, while, break, else, not.

The name has to be unique (only used once), but you can have different cases (one uppercase and one lowercase).

Possible Name Errors


When you create a variable name, if you see a “Name Taken” error, it means there is a duplicate name in any of the groups above.

You may encounter a case when opening a project made in an earlier version of VEXcode EXP that has a duplicate variable name. This will cause an error when compiling and you will see the following type of error message

The error message above shows the following problems:

  • The name “myvariable” was found as a numeric variable and a boolean variable. 
  • The name “awesomeVar” was found as a numeric variable and a boolean variable. 

To resolve the error, one of the duplicates will need to be removed or changed so they are unique.

For more information, help, and tips, check out the many resources at VEX Professional Development Plus

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