The Glish language includes a number of predefined functions for aiding in
writing Glish scripts. These include functions for identifying and
converting types, manipulating vectors and strings, storing and reading
values to and from files, dealing with variable argument lists in
functions, and manipulating agent's. Glish also includes predefined
global variables for accessing the script's arguments and environment, for
inspecting and responding to changes in the system's state, and for running
a script as clients (§ 7.10, page 
).
We discuss each of these in turn.