Some Computer Science Terminology

[Este post é em inglês. Se não entender, use um tradutor. Os links para a Wikipedia podem ser consultados em suas versões em português, portanto você ainda pode tirar algo proveito daqui.]

I wrote this as an email to someone special, but then I thought it could be shared here.

It is simply a few links and comments for topics we were talking about one night... you might get interested as well -- and feel free to join the conversation.

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Hello dear reader!

Words in bold are terms that are interesting to be familiarized with, IMHO.

Context

http://en.wikipedia.org/wiki/Context_(computing)

(Additional term linked above: State http://en.wikipedia.org/wiki/State_(computer_science))

Environment

Note that in Scheme an environment is a first-class object, which means it can be assigned to a variable, it can be passed as argument, it can be used just like a number or string, etc etc.

Note also how Common Lisp and Scheme (and most other programming languages that I am familiar with and that I can think about now) differ in number of environments. CL is said to be a Lisp-2, while Scheme is Lisp-1. It means that Scheme has only one lexical environment containing all functions and variables, while CL has two distinct environments, one only for functions and another, independent one, for variables.

You can also think of the terms scope and namespace, which can appear to play a similar role in several languages.

http://www.gnu.org/software/mit-scheme/documentation/mit-scheme-ref/Environment-Operations.html

http://en.wikipedia.org/wiki/Scope_(programming)

http://en.wikipedia.org/wiki/Namespace_(programming)

Turing Machine

Have in mind how little you need to have a computing machine (and think of what does it mean to "compute," by the way). Have in mind that the Turing Machine is not practical as a real computer, but is of fundamental theoretical importance.

http://en.wikipedia.org/wiki/Turing_machine

http://en.wikipedia.org/wiki/Alan_Turing

(John) von Neumann

http://en.wikipedia.org/wiki/John_von_Neumann

http://en.wikipedia.org/wiki/Von_Neumann_architecture

Escolhendo um Lisp: do Clojure ao Racket

Graças a um email de um amigo, o Lucas Teixeira, finalmente escrevi algumas coisas que já vinha comentando com algumas pessoas, geralmente nos pós-dojos.

Era pra ser um email pro Lucas, mas acabei expressando coisas que poderiam ficar públicas.

Bem, ele começou dizendo no email:

Então... sempre quis aprender programação funcional. Já tentei Haskell, LISP, Scheme, mas nunca pegou de verdade.

Tô tentando aprender Clojure agora. Baixei o Clojure Box e uns tutoriais da Internet. Tô resolvendo uns problemas do Project Euler e o clojure-koans.

Tem alguma dica de material?

Que tipo de coisa você tá / tava fazendo com Clojure?

Cara, foi muito surpreendente seu email.

Vamos a um apanhado de impressões sobre algumas linguagens da família lisp, começando com Clojure, passando por Common Lisp, Scheme e chegando em Racket.