sh-dsl syntax sugar ideas

[veqqq]

A more elegant way of calling env variables could be interesting. Currently we can do: ,(string ($<_ echo $HOME) "/folder") or ,(string (os/getenv "HOME") "/folder") but maybe e.g. (env $HOME) or even (env :home) could be nice, transparently implemented as the above. (I have no idea how to safely implement just using $HOME directly.) Unfortunately ~ can't be a binding. 💃

(get-env :home) might be more Janety, but I'm not sure if redoing the whole API makes sense that way. More direct, implementing something like:

(defn- fetch-env []
(def e @{})
(each line (string/split "\n" (string/trim ($< env)))
  (def [k v] (string/split "=" line 0 2))
  (put e k v))
e)

Could let you do: (defn env [s] ((fetch-env) s)) allowing (env "PWD") but exposing the map directly could be optimal e.g. an API like ((fetch-env) "PWD"). Naming is of course an issue, we do have the model of curenv though.

LispE has some inspiring features: https://www.youtube.com/watch?v=aeUt0x7EqPY

Racket's Rash https://www.youtube.com/watch?v=Acjqx1MPkw4 h/t sogaiu

What do others thing of such things? Does anything else seem useful? N.b. much of my use case is jumping immediately into a Janet repl instead of bash, so short things feel extra convenient. If others don't find such use cases relevant, it'd make more sense to add them to a personal utility lib (and name it "s" for a short (use s)!)

[sogaiu]

@ianthehenry's book has a chapter that has some coverage of janet-sh.

The following bits are extracted [1] (and slightly modified) from the end of the scripting chapter:

• there is no analog of the extremely-useful cp foo.bar{,.bup} expansion shorthand
• it’s a lot more verbose to set and reference environment variables in Janet
• there’s no ~/foo or ~user/foo shorthand for specifying home directories

The last two items seem to have overlap with what's mentioned above.

I rarely use the curly brace item (cp foo.bar{,.bup}), but may be others do?

---

[1] There were some other things mentioned but IIUC they are not so obviously related to syntax sugar.