token

1. grammar A basic, grammatically indivisible unit of a

language such as a keyword, operator or identifier.

Compare: lexeme.

2. convention (Or "pumpkin") An abstact concept passed

between cooperating agents to ensure synchronised access to a

shared resource. Such a token is never duplicated or

destroyed (unless the resource is) and whoever has the token

has exclusive access to the resource it controls. See for

example token ring.

If several programmers are working on a program, one

programmer will "have the token" at any time, meaning that

only he can change the program whereas others can only read

it. If someone else wants to modify it he must first obtain

the token.

(1999-02-23)