Extend with support for generic streams.

[BenjaminHolland]

Pattern matching on characters is great, but seems unnecessarily restrictive. Being able to "parse" streams of any given type would seem to be a powerful tool.

[ztl8702]

+1. I wrote a "Tokenizer" with FParsec which produces a flat list of tokens from CharStream, and now is wondering what can do with the "stream" of tokens...

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Hmm seems https://github.com/benjamin-hodgson/Pidgin allows arbitrary input type... so I might use both libraries 🤦