EPL keywords are case sensitive. They are reserved words that are an intrinsic part of the language, and must not be used as identifiers (for example, monitor, print and event). See also Identifiers.

There are also some words that EPL may use as keywords in a future release, and you should avoid using them as identifiers (for example, public, class and byte).

Software AG Designer and the correlator will warn you if you attempt to use a keyword or a word reserved for future use.

If you absolutely have to use a keyword or a word reserved for future use as an identifier, then you have to prefix this word using the hash symbol (#). This may be the case if an external system mandates a particular field name in an event type. For example, if an externally created digital event type has a field name that is an EPL keyword, such as action, you would have to specify #action as the field name. Adding the hash symbol (#) makes sure that EPL accepts a keyword as an identifier. Internally, however, Apama treats #action as action.