Rules for character SAS informat names

When creating a new SAS character informat, the list of rules must be followed.

• The first character must be a dollar sign ($) - this differentiates it from a numeric format (numeric informats do not begin with dollar sign)
• The second character must be a letter or underscore
• Subsequent characters can be letters, underscores, or digits
• Cannot be more than 31 characters (SAS adds a leading @ sign to consider it as an informat - this enables us to have a format and informat with the same name)
• The informat name cannot end with a number
• The informat name should not be same as any SAS defined informats