I've been playing with Haskell, trying to create a very simple website using Servant and Lucid. At the moment I reached the stage "My code works, I have no idea why". I tried creating Bootstrap button. According the the doc, it should be defined as:
<button type="button" class="btn btn-primary">Primary</button>
So I found Lucid.Html5 doc: https://hackage.haskell.org/package/lucid-2.9.11/docs/Lucid-Html5.html and worked out the function that creates a button:
button_ :: Term arg result => arg -> result
After spending some time trying to work out the correct syntax, I came up with this:
-- correctly replicates the html pasted above
button_ [type_ "button", class_ "btn btn-primary"] "Primary"Typically I would have called it a victory and focused on other tasks, but this one looks like a true piece of magic to me.
The doc says "button_" is a function that takes an argument "arg" and returns a value of a generic type "result". However, in my application "button_" clearly takes two arguments and returns "Html ()".
-- f arg arg again ??
button_ [type_ "button", class_ "btn btn-primary"] "Primary"It must do something with the "Term" typeclass, but I'm not sure how to understand it. Can someone help me with this ? I tried loading the module into ghci and inspecting types with ":t", but that didn't help me too much.