Clojurians Log v2

Hi! I'm doing my first experiments with clj and noticed that I can put this into my deps.edn:

:aliases {:foo {:main-opts ["-e" (let [x :foo] (println x))]}

clojure -M:foo should run that expression. Unless you really use an expression a great deal or need it for some kind of work-around, I don't see the value myself. It seems simpler to use the -e flag on the command line.

There are a whole range of example aliases in https://github.com/practicalli/clojure-deps-edn

I'd like to put clojure forms into the aliases as examples. Putting them on the command line would make them platform dependent. So I just wanted to check that putting them there is fine.

That embedded Clojure form there is not valid syntax in deps.edn

So putting that there is not fine

:main-opts is a vector of strings

@alexmiller thanks for the clarification

Hi all, wondering if there's a way to retrieve the resolved deps environment, specifically the fully resolved :paths attribute after all the aliases have been merged and a main function has been launched? Thanks!

@zalky Not really. By the time your code is actually running, a lot of that information has been merged away.

You can use tools.deps.alpha as a library to compute the “project basis” which is a superset of everything in the root deps.edn, user deps.edn, and project deps.edn files but you can’t tell which aliases were used to invoke your code — only what different paths/deps combinations would be computed from any given aliases.

You can get the classpath though — which might be enough for your needs — via a JVM system property.

(System/getProperty "java.class.path")

Thanks @seancorfield, this is very helpful. If I filter that list for directories, would that be equivalent to the fully resolved paths? Might there be anything else thrown in? My motivation is that I'm doing some work with clojure.tools.namespace and I need to know all the directories I might have source in.

You’ll get directories for the equivalents of src, resources, and maybe test plus any git deps or local/root deps in play.

You could probably filter out any absolute paths and what is left should be just your own project’s stuff (depending on how you have your project set up).

Gotcha, thanks!

what's your actual goal? project paths?

Hi @alexmiller, I have a clojure.tools.namespace based reloaded workflow, which requires as input a set of directories to watch for changes. While I can supply a list of hard-coded directories in :main-opts , my understanding is that project paths is dynamically computed from all the active aliases.

it is, but there is not an explicit place to get just the paths

the classpath computed by tools.deps will put all paths at the front of the classpath though

So you could just walk the (System/getProperty "java.class.path") while it's directories. To be more righter, could probably only take the paths in your project (local or git deps could also be dirs and happen to be at the front)

Thanks, I'll give the classpath approach a go.

Why are you using c.t.n / reloaded? I've never felt the need for that sort of thing (and my REPLs run for weeks, sometimes months).

I'm always curious when I find folks using this workflow and -- as in your case -- jumping through hoops to make it work...?

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