Language tutorial

This tutorial introduces the CIF language. It explains the general idea behind the concepts of the language, and shows how to use them, all by means of examples. The tutorial is focused on giving a short introduction to CIF, and does not cover all details. It is recommended reading for all CIF users.

Introduction

CIF is primarily used to create models of physical systems and their controllers, describing their behavior. However, CIF is a general-purpose modeling language, and can be used to model practically anything, ranging from physical real-world systems to abstract mathematical entities.

CIF supports discrete event models, that are mostly concerned with what happens, and in which order. CIF also supports timed systems, where timing plays an explicit role, and hybrid systems, which combine the discrete events with timing. This makes CIF suitable for modeling of all kinds of systems.

The CIF tooling puts a particular focus on supporting the entire development process of controllers. However, just as the CIF language, the CIF tooling can be applied much more generally. The tooling allows among others specification, supervisory controller synthesis, simulation-based validation and visualization, verification, real-time testing, and code generation.

CIF originally stood for Compositional Interchange Format for hybrid systems. As the language has since evolved beyond its original purpose, the name 'CIF' is nowadays only used in its abbreviated form.

Lessons

Several lessons are available, grouped into the following categories:

The lessons introduce new concepts, one by one, and are meant to be read in the given order.

Basics

Automata

Explains automata, locations, events, edges, transitions, and more.

Synchronizing events

Explains event synchronization, enabledness, traces, and state spaces.

Non-determinism

Explains multiple causes of non-determinism.

Alphabet

Explains alphabets for both individual automata and entire specifications.

Event declaration placement

Explains the placement of event declarations.

Shorter notations

Explains several shorter notations, including self loops, declaring multiple events with a single declaration, multiple events on an edge, and nameless locations.

Data

Discrete variables

Explains discrete variables, guards, and updates.

Discrete variable value changes

Explains how and when discrete variables can change value.

Location/variable duality (1/2)

Explains the duality between locations and variables using a model of a counter.

Location/variable duality (2/2)

Explains the duality between locations and variables using a model of a lamp.

Global read, local write

Explains the concepts of global read and local write.

Monitoring

Explains monitoring, self loops, and monitor automata.

Old and new values in assignments

Explains old and new values of variables in assignments, multiple assignments, and the order of assignments.

The tau event

Explains the tau event.

Initial values of discrete variables

Explains initialization of discrete variables, including the use of default values and multiple potential initial values.

Initialization predicates

Explains initialization in general, and initialization predicates in particular.

Using locations as variables

Explains the use of locations as variables.

State (exclusion) invariants

Explains state (exclusion) invariants.

State/event exclusion invariants

Explains state/event exclusion invariants.

Types and values

Types, values, and expressions

Explains the concepts of types, values, and expressions, as an introduction for the other lessons in this category.

Values overview

Provides an overview of the available values, and divides them into categories.

Integers

Explains integer types, values, and commonly used expressions.

Ranged integers

Explains ranged integers.

Reals

Explains real types, values, and commonly used expressions.

Booleans

Explains boolean types, values, and commonly used expressions.

Strings

Explains string types, values, and commonly used expressions.

Enumerations

Explains enumeration types, values, and commonly used expressions.

Tuples

Explains tuple types, values, and commonly used expressions.

Lists

Explains list types, values, and commonly used expressions.

Bounded lists and arrays

Explains bounded lists, arrays, and their relations with regular lists.

Sets

Explains set types, values, and commonly used expressions.

Dictionaries

Explains dictionary types, values, and commonly used expressions.

Combining values

Explains how to combine values of different types.

If and switch expressions

Explains if and switch expressions.

Scalable solutions and reuse (1/2)

Constants

Explains the use of constants.

Algebraic variables

Explains the use of algebraic variables.

Algebraic variables and equations

Explains the use of equations to specify values of algebraic variables.

Type declarations

Explains the use of type declarations.

Time

Timing

Introduces the concept of timing.

Continuous variables

Explains the use of continuous variables.

Continuous variables and equations

Explains the use of equations to specify values of continuous variables.

Equations

Show the use of equations for both continuous and algebraic variables, by means of an example of a non-linear system.

Variables overview

Provides an overview of the different kinds of variables in CIF, and their main differences.

Urgency

Explains the concept of urgency, as well as the different forms of urgency.

Deadlock and livelock

Explains the concepts of deadlock and livelock.

Channel communication

Channels

Explains point-to-point channels and data communication.

Dataless channels

Explains void channels that do not communicate any data.

Combining channel communication with event synchronization

Explains how channel communication can be combined with event synchronization, further restricting the communication.

Functions

Functions

Introduces functions, and explains the different kind of functions.

Internal user-defined functions

Explains internal user-defined functions.

Function statements

Explains the different statements that can be used in internal user-defined functions.

Functions as values

Explains using functions as values, allowing functions to be passed around.

Scalable solutions and reuse (2/2)

Automaton definition/instantiation

Explains using automaton definition and instantiation for reuse.

Parametrized automaton definitions

Explains parametrized automaton definitions.

Automaton definition parameters

Explains the different kinds of parameters of automaton definitions.

Groups

Explains hierarchical structuring using groups.

Group definitions

Explains groups definitions and parametrized group definitions.

Imports

Explains splitting CIF specifications over multiple files using imports.

Imports and libraries

Explains how to create libraries that can be used by multiple CIF specifications using imports, as well as how to use imports to include CIF specifications from other directories.

Imports and groups

Explains how imports and groups interact.

Namespaces

Explains namespaces, and how they can be used together with imports.

Input variables

Explains input variables, how they can be used for coupling with other models and systems, and their relation to imports.

Stochastics

Stochastics

Introduction to stochastic distributions, which allow for sampling, making it possible to produce random values.

Discrete, continuous, and constant distributions

Explains the different categories of stochastic distributions: discrete, continuous, and constant distributions.

Pseudo-randomness

Explains how computers implement stochastics using pseudo-random number generators, and how this affects the use of stochastics in CIF.

Language extensions

Supervisory controller synthesis

Explains how to extend a model to make it suitable for supervisory controller synthesis.

Annotations

Explains how to annotate elements of the specification with extra information.

Print output

Explains how to extend a model to include printing of textual output.

This documentation is currently not part of the language tutorial, but of the simulator tool documentation.

SVG visualization

Explains how to extend a model to couple it to an image for visualization.

This documentation is currently not part of the language tutorial, but of the simulator tool documentation.

SVG interaction

Explains how to extend a model to couple it to an image for interaction via a visualization.

This documentation is currently not part of the language tutorial, but of the simulator tool documentation.