Glossary of Terms

sequencer

1. The project that defines SNL and provides an implementation.

2. The runtime library that supports execution of SNL programs.

cpp

The C preprocessor. Normally not a stand-alone program but part of the C compiler. Can be abused to preprocess SNL code, too, which is a constant source of compatibility problems.

snc

The SNL compiler. See Compiling SNL Programs.

SNL

State Notation Language. What this project is about.

assigned

The property of a variable or array element to occur in an assign clause in an SNL program.

PV

process variable

A mutable variable that is globally visible and accessible via some network protocol in a distributed control system, such as one based on EPICS.

CA

Channel Access

The EPICS network protocol, used to connect client programs to PVs hosted on a server.

EPICS

Experimental Physical and Industrial Control System. A set of tools and libraries for building large distributed soft real-time control systems.

state set

SNL jargon for finite state machine. A program may contain multiple state sets and each runs in its own thread.

true

Any non-zero value, as in C.

false

Zero, as in C.