Variable Naming

Variables in Retro Rocket BASIC must follow the following rules:

1. Variables must start with an alphabetic character or an underscore, e.g. A-Z, a-z or _.
2. Variables can contain numeric characters, so long as those numeric characters are not the first character.
3. After the first character, a variable may contain any alphanumeric or underscore character in any position
4. Variable names have a maximum length of 60 characters. This does not include any array indexes and is to help aid readability.
5. Variable names may be suffixed with a single $ to denote a string variable, or a single # to denote a real variable (floating point). These symbols are not permitted anywhere else in the variable name.
6. Variable names are CaSe SeNsItIvE.
7. Variable names cannot start with a keyword or built in function name

In summary, the following regular expression could be considered to match all valid Retro Rocket BASIC variables:

/[A-Za-z_][A-Za-z_0-9]{1,58}(\$|#|[A-Za-z_0-9])/