Allowed characters for names in metamodels

[enikao]

Which characters can be used for instances of Metamodel.qualifiedName and NamespacedEntity.simpleName?

Arguments for limiting to small set (e.g. ASCII):

• Safe

Arguments for big set (e.g. UTF-8):

• We want to name semantic elements according to their domain, which might be Chinese characters for a chinese banking system.

Do we allow spaces in names?

[enikao]

On 2023-07-07, we decided to only allow programming language identifiers. More specifically, we allow Java identifiers (https://docs.oracle.com/javase/specs/jls/se20/html/jls-3.html#jls-3.8) with the following modifications:

• We do NOT allow $ (dollar sign)
• ReservedKeyword, BooleanLiteral, and NullLiteral (as per Java identifier spec) are allowed identifiers.

Effectively:

• Names MUST NOT start with a number.
• Names MUST NOT be empty.
• Names MUST NOT contain spaces.
• Names CAN use Unicode characters, numbers, and underscore.

Note: These restrictions only apply to names of Language elements (i.e. M3 concepts/M2 instances). Any language that uses INamed on its own can establish their own constraints.