commit bad6fc892356595f8809a01e3a0d9dc4bccc78ca · kitten.sh/wonka

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src/callbag_types.re
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       /*

     

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         A sink has the signature: `signalT('a) => unit`

     

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         A source thus has the signature: `sink => unit`, or `(signalT('a) => unit) => unit`

     

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         Effectively a sink is a callback receiving signals as its first argument.

     

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         - Start(talkback) will be carrying a talkback using which the sink can attempt

     

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           to pull values (Pull) or request the source to end its stream (End)

     

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         - Push(payload) carries a value that the source sends to the sink.

     

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           This can happen at any time, since a source can be both pullable or

     

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           merely listenable.

     

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         - End signifies the end of the source stream, be it because of a talkback (End)

     

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           or because the source is exhausted.

     

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         In detail, a talkback is simply a callback that receives a talkback signal as

     

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         its first argument. It's thus typically anonymously created by the source.

     

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         A source is a factory that accepts a sink. Calling a source with a sink will

     

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         instantiate and initiate the source's stream, after which the source sends the sink

     

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         a talkback (Start(talkback)). This is called the "handshake".

     

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         Typically an operator factory won't call the source with a sink it receives

     

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         immediately—because this would cause the operator to simply be a noop—but instead

     

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         it will create an intermediate sink with the same signature to perform its own

     

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         logic.

     

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         At that point the operator can for instance intercept the talkback for its own

     

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         purposes, or call the actual sink as it sees fit.

     

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        */

     

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       type talkbackT =

     

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         | Pull

     

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         | End;