What is the format of valid entrypoint names?

Question

Are there any constraints on valid entrypoint names?

Answer 1

The entrypoint name must be a valid annotation:

An annotation is a sequence of characters that matches the regular expression @%|@%%|%@|[@:%][<sub>0</sub>-9a-zA-Z][<sub>0</sub>-9a-zA-Z\\.%@]\*. Note however that @%, @%% and %@ are special annotations and are not allowed everywhere.

Furthermore, entrypoint names are also limited to 31 characters.

(Note: there is a currently a bug that permits invalid entrypoint annotations to be given to literal address. Such addresses should not be expected to function normally.)

While in no way reserved, the entrypoint name %root is often used by convention to name the root when using a %default entrypoint).