A.1.1 Identifiers

Identifiers in CSP_M begin with an alphabetic character and are followed by any number of alphanumeric characters or underscores optionally followed by any number of prime characters ('). There is no limit on the length of identifiers and case is significant. Identifiers with a trailing underscore (such as `fnargle_') are reserved for machine-generated code such as that produced by Casper [Lowe97].

CSP_M enforces no restrictions on the use of upper/lower case letters in identifiers (unlike some functional languages where only datatype constructors can have initial capital letters). It is, however, common for users to adopt some convention on the use of identifiers. For example

• Processes all in capitals (BUTTON, ELEVATOR_TWO)
• Types and type constructors with initial capitals (User, Dial, DropLine)
• Functions and channels all in lower-case (sum, reverse, in, out, open_door)

Note that while it is reasonable to use single character identifiers (`P', `c', `T') for small illustrative examples, real scripts should use longer and more descriptive names.

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