Implemented help commands and added notice thereof to help output
#584
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| output += m::text("Numbat supports a number of commands. Use ") | ||
| + m::string("help commands") | ||
| + m::text(" for more info.") | ||
| + m::nl(); |
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I'm not 100% satisfied with the phrasing here. Numbat (the language) doesn't really support any commands. You can't write quit in a Numbat program, for example. It's really the different REPL/CLI interfaces that support certain commands. And that leads me to the other problem here: with the current implementation, this message will also be displayed in the web version. But help commands doesn't work there, and if it did, it would have to show a different list of commands.
I really like this new feature and the help commands output looks great! But I think we need to work on the web version first. As I said elsewhere, it would be great if we could share command-parsing code between different "frontends". We would then need a way to customize (1) which commands are available and (2) how some of them are implemented in a particular frontend, e.g. using a trait or using simple callbacks.
In some sense, the whole command-parsing/handling thing probably doesn't even belong in the numbat crate. It's not part of the compiler or the language implementation. Even now, there are some frontends (IRC bot, mobile app, Jupyter kernel) that don't make use of commands. So they could be moved to a separate crate (numbat-commands or similar). But I guess for simplicity, we can also leave the code in the numbat crate for now. We also have things like unicode_input.rs that are only used in specific frontends.
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Thanks, you're right. I'm definitely too CLI-centric 😄. I'll need to think about how to share almost-the-same code between frontends. A numbat-commands crate probably does sense, with features to enable/disable various commands. Then in the commands code, just slap a #[cfg(feature)] on every branch of every match statement.
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I had something else in mind. Let's maybe discuss different options first. I'll try to write down what I thought about tomorrow.
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I had something else in mind. Let's maybe discuss different options first. I'll try to write down what I thought about tomorrow.
Curious to hear what your idea was.
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