Xerl: two modules

03 Feb

Everything is an expression. This sentence carries profound meaning. We will invoke it many times over the course of these articles. If everything is an expression, then the language shouldn’t have any problem with me defining two modules in the same source file. mod first_module begin end mod second_module begin end Likewise, it shouldn’t have any problem with me defining a module inside another module. mod out_module begin mod in_module begin end end Of course, in the context of the Erlang VM, these two snippets are equivalent; there is nothing preventing you from calling the in_module module from any other module.

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Xerl: empty modules

30 Jan

Let’s build a programming language. I call it Xerl: eXtended ERLang. It’ll be an occasion for us to learn a few things, especially me. Unlike in Erlang, in this language, everything is an expression. This means that modules and functions are expression, and indeed that you can have more than one module per file. We are just starting, so let’s no go ahead of ourselves here. We’ll begin with writing the code allowing us to compile an empty module.

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Build an FTP Server with Ranch in 30 Minutes

14 Nov

Last week I was speaking at the London Erlang Factory Lite where I presented a live demonstration of building an FTP server using Ranch. As there was no slide, you should use this article as a reference instead. The goal of this article is to showcase how to use Ranch for writing a network protocol implementation, how Ranch gets out of the way to let you write the code that matters, and the common techniques used when writing servers.

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Erlang Tic Tac Toe

17 Oct

Everyone knows Tic Tac Toe, right? Players choose either to be the Xs or the Os, then place their symbol on a 3x3 board one after another, trying to create a line of 3 of them. Writing an algorithm to check for victory sounds easy, right? It’s easily tested, considering there’s only 8 possible winning rows (3 horizontal, 3 vertical and 2 diagonal). In Erlang though, you probably wouldn’t want an algorithm.

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