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Comment by anhner | Hacker News Reader

Sorry for my ignorance, but what kind of lisp has piping? Or what is the vertical line operator called?

    (torus :z 60 30
    | twist :y 0.07
    | rotate-pi :y t :z 0.05
    ...

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This is described later in the tutorial (ctrl-f "lisp heresy"). It's a macro that I wrote, not something built into Janet -- I'm sure I'm not the first person to do this, but I'm not aware of any lisps that have such a construct built-in.

Clojure has the thread first/last macros -> and ->> which pipes each result to the next form.

Yeah, and Janet copies Clojure's threading macros (that's how I implemented pipe syntax -- split on pipes, add some parens, and stick them into a -> form). I've just never seen it done infix like this -- it's very convenient when you don't have something like paredit to quickly wrap an expression.

And this is why Lisp is amazing. Seeing the question I immediately thought “this looks like a really nice convenience macro for the author’s preferred formatting”!

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