Difference between revisions of "User:Echo Nolan/Reactive Banana: Straight to the Point"
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sequence_ . intersperse (threadDelay 125000) $ map playNote [C2 ..] |
sequence_ . intersperse (threadDelay 125000) $ map playNote [C2 ..] |
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sequence_ . intersperse (threadDelay 62500) $ map playNote [C2 ..] |
sequence_ . intersperse (threadDelay 62500) $ map playNote [C2 ..] |
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+ | </pre-haskell> |
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+ | You've probably figured out by now that C2 and C6 are data constructors. Here's the definition for my Note type. |
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+ | <pre-haskell> |
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+ | data Note = C2 | C3 | C4 | C5 | C6 deriving (Show, Enum) |
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</pre-haskell> |
</pre-haskell> |
Revision as of 17:39, 18 September 2012
Introduction
So I'm writing this tutorial as a means of teaching myself FRP and reactive-banana. It'll probably be full of errors and bad advice, use it at your own risk.
All the tutorials on FRP I've read start with a long boring theory section. This is an instant gratification article. For starters, imagine a man attempting to sharpen a banana into a deadly weapon. See? You're gratified already! Now for a boring bit:
Go install mplayer: <code-bash>apt-get install mplayer # Or equivalent</code-bash>
Get the git repository associated with this tutorial: <code-bash>git clone https://github.com/enolan/rbsttp.git </code-bash>
Install reactive-banana <code-bash> cabal install reactive-banana</code-bash>
Musical interlude
Cd into the git repo and open rbsttp.hs in GHCi:
<pre-bash> cd rbsttp ghci rbsttp.hs </pre-bash>
Now, we can make some beepy noises. Try these:
<pre-haskell> playNote C2 playNote C6 sequence_ . intersperse (threadDelay 1000000) $ map playNote [C2 ..] </pre-haskell>
Play with the value passed to threadDelay a bit for some more interesting noises. It's expresssed in microseconds.
<pre-haskell> sequence_ . intersperse (threadDelay 500000) $ map playNote [C2 ..] sequence_ . intersperse (threadDelay 250000) $ map playNote [C2 ..] sequence_ . intersperse (threadDelay 125000) $ map playNote [C2 ..] sequence_ . intersperse (threadDelay 62500) $ map playNote [C2 ..] </pre-haskell>
You've probably figured out by now that C2 and C6 are data constructors. Here's the definition for my Note type.
<pre-haskell> data Note = C2 | C3 | C4 | C5 | C6 deriving (Show, Enum) </pre-haskell>