使用 Haskell 创作音乐 #4

1. Mezzo

Mezzo 是一个可以描述音乐的领域内编程语言 / Haskell 库，它可以对不同的音乐创作模式进行静态检查（类似于静态类型检查，这当然也是得益于 Haskell 的类型检查系统），也就是说，如果你创作了“坏”的音乐，你的作曲将不会被编译 – think of it as a very strict spell-checker for music.

import Mezzo

comp = defScore $ start $ melody :| c :| d :| e :| f :>> g

main :: IO ()
main = renderScore "comp.mid" "First composition" comp

Save, build and execute. You should get a .mid file in the project directory which looks something like this:

To test the correctness checking, change the d note in comp to a b. You should see the following when you save the file:

• Major sevenths are not permitted in melody: C and B
• In the first argument of ‘(:|)’, namely ‘melody :| c :| b’
  In the first argument of ‘(:|)’, namely ‘melody :| c :| b :| e’
  In the first argument of ‘(:>>)’, namely
    ‘melody :| c :| b :| e :| f_’

Mezzo has two ways of composing music: sequential (melodic) and parallel (harmonic) composition ...

2. 一本很棒的书: http://euterpea.com/haskell-school-of-music/

• 使用 Haskell 编程语言探索计算机音乐和函数式编程的基础。

3. 其他的框架和库:

   • csound-expression - 专注于电子音乐的创作

   • th.composer - 由 raptazure@λ-magic 创建

   th.composer 的一个视频演示：https://github.com/raptazure/presentations/blob/master/haskell-music/music.mp4