What's the idiomatic way to use external module in macro?

[tupini07]

As the title says, what's considered the most idiomatic way to use a module inside a macro. For example, the naive (dirty) way would be to

# macros.janet
(import some-module)

(defmacro a-macro []
    ~(some-module/function params))

and then use it as

# some-file.janet
(import some-module) # < need to import this even if we don't use it directly
(import ./macros)

(a-macro)

The issue here is that some-file.janet needs to import some-module, even though it's not using it directly. Is there a way in which I can require the module directly inside the body of the macro so I don't need users to import it separately? If import gave me a table of symbols I imagine this could be done with let as:

(let [sm (import some-module)]
   (sm/function params))

But unless I missed something while going through the documentation there is no way to do this in Janet 🤔

[bakpakin]

The as-macro macro is a hack for this.

(import my-other-module)

(defmacro my-second-macro
  [x y z]
  ~(+ ,x
      (,my-other-module/some-fn ,y)
      (as-macro ,my-other-module/first-macro ,z)))

It allows you to use the same unquote trick for hygiene on macros as you use on functions. Note that as-macro is not unquoted.

[bakpakin]

This also has the benefit that you don't need to import my-other-module when using my-second-macro - the macro is essentially inlined for you. The caveat is that you cannot override the as-macro binding or this breaks, but you shouldn't be overriding core bindings anyway in most code.

[tupini07]

Great, thanks a lot! That's exactly what I was looking for. I probably missed it while going through the documentation on Janet's site