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2.4 Procedures and variables

THUD exists to serve the user, providing procedures and variables that do various useful things. The user can call these procedures and set the values of these variables in one of two ways: through a script, or through an interactive session.

A script is a Scheme program executed in the THUD environment. The normal way to do this is to specify -x FILE on the command line. See Command-line processing. Scripts using THUD services are also known as "drivers" (see Code and data).

An interactive session is where you interact with one of THUD's "faces", issuing to it "commands" that are translated underneath the face into the appropriate calls to these procedures. We distinguish the term "command" from "procedure" because a command need not have the same name as the procedure it calls. See Faces, for more info.

There are several categories of procedures. See the docstrings of each procedure for more info. Variables control how things work.