Chapter 1  An introduction to Lucid Synchrone

This section is a tutorial introduction to Lucid Synchrone. A good familiarity with general programming languages is assumed. Some familiarity with (strict or lazy) ML languages and with existing synchronous data-flow languages would be helpful since the language incorporates features from both families. Some references are given at the end of this document.

For this tutorial, we suppose that programs are written in a file tutorial.ls.

• The core language
  • Point-wise Operations
  • Delays
  • Global declarations
  • Combinatorial Functions
  • Sequential Functions
  • Anonymous Functions
  • Local definitions and Mutually Recursive Definition
  • Shared Memory and Initialization
  • Causality check
  • Initialization check
• Multi-clock systems
  • Sampling: the operator when
  • Combining Sampled Streams: the operator merge
  • Oversampling
  • Clock constraints and error messages
  • Equality and scope restrictions in the use of clocks
• Static Values
• Data-types, Pattern matching
  • Type definitions
  • Pattern matching
  • Local Definitions
  • Implicit Definition of Shared Variables
• Valued Signals
  • Signals as Clock Abstraction
  • Testing the Presence and Signal Matching
• State Machines
  • Strong Preemption
  • Weak Preemption
  • ABRO and Modular Reseting
  • Local Definitions in a State
  • Communication between States and Shared Memory
  • The Particular Role of the Initial State
  • Resume a Local State
• Parameterized State Machines
• State Machines and Signals
  • Pattern Matching over Signals
  • The derived operator await/do
• Alternative Syntax for Control Structures
• Higher-order Reactive Features
  • Composing Functions
  • Combinators
  • Streams of Functions and Functions of Streams
  • Instantiating Streams of Functions
• Non reactive higher-order features