Erlang By Example

Erlang By Example Course Contents

Course: Erlang By Example Targeted Audience: Software Developers Requirements: Good programming skills. Objectives: Understanding of the basics of Erlang. Read/Write/Design Erlang Programs. Good knowledge of the development environment and tools. Understanding of the good and bad programming practices. Goal: Attend the OTP course and eventually pass the Erlang certification exam. Duration: Five days. Erlang By Example is a five day introductory course aimed at software engineers. Its objectives are to give participants the knowledge to read, write and structure Erlang programs, providing all prerequisites to attend the Advanced Erlang/OTP course. The course contains all the Erlang basics such as sequential and concurrent programming, along side error handling and the latest language extensions. The Erlang development environment is presented, with a special emphasis on the Erlang mode for Emacs alongside the major debugging tools. Good and bad programming practices are discussed, as are tools used to profile the system. OTP design principles and concepts are sneaked into the material as well as the exercises.

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Introduction We start off with an introduction of the software needs of telecom control systems, followed by a history of Erlang, its features, and product and research examples within and outside Ericsson. Basic Erlang This section deals with Erlang data types and pattern matching. Functions, modules, and BIFs are discussed. Before the exercises, the Erlang shell, useful shell commands as well as Emacs and its Erlang mode are introduced. Sequential Programming The Sequential Programming section comprehends conditional evaluations, guards and scope of variables. It then introduces recursion, with a special emphasis on different recursive patterns, tail recursion, and space saving optimizations. Before the exercises, libraries and their manual pages, possible run time errors and the debugger are demonstrated. Concurrent Programming This section describes the creation of processes and their life span. It looks at sending and receiving messages, selective reception, and passing data in the messages. It continues with the various uses of time outs and registering processes, and terminates by showing the generic process code structure. Before the exercises, a demonstration of the Process Manager tool is given. Process Design Patterns This section introduces the concept of process patterns, preparing the students for the OTP behaviours. It gives a detailed example of a client server system, looks at finite state machines and event handlers. Synchronous versus asynchronous message passing is discussed. Process Error Handling This section introduces the simple but powerful error handling mechanisms in processes. It looks at process links, exit signals and their propagation semantics. How robust systems are built in Erlang are discussed, and an example from the Process Design Patterns section is re-implemented, making it robust. Code Updating The section introduces software upgrade during run time. The error handler, the code server, and code search paths are covered, as is the .erlang file. Records and Funs The syntax and semantics of records is introduced, with a special emphasis on pattern matching. Funs are covered, as are higher order functions. Plenty of examples are given for both constructs.

ETS tables An introduction to the Erlang Term Storage is given, together with its different table options. Examples on when to use and not to use ETS tables are covered. A demonstration of the table visualizer is provided. Distributed Programming An introduction to the requirements of distributed systems is given, and how Erlang is able to fill these requirements. The distribution syntax and semantics are covered, followed by the BIFs and the net kernel.

Advanced Constructs List comprehensions and their usage are explained. References are discussed. This is followed by Binaries, and the Bit syntax, where pattern matching can be applied directly to incoming structures. Lastly, bit wise and logical operators are described. This section also covers Macros, with examples on how they can be used for debugging purposes.

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Ports and Sockets An introduction of the mechanisms used to make Erlang more open are taken up in this section. Ports, for external communication within the same machine, and Sockets, for communication on IP networks are discussed. The difference between TCP and UDP is described. Style and Efficiency This section gives an introduction to writing efficient Erlang Programs. The efficiency section describes how binaries can be used to handle large amounts of data which have to be sent between processes, how tail recursion can prevent bursts of memory usage, as well as other simple optimisations based on the implementation of the virtual machine and its garbage collector. It then goes ahead with suggestions and guidelines on how to keep the code neat and readable and terminates with a few slides on coding strategy.

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