Clojurians Log v2

Hello Use case: I am trying to load a file that has a few functions that will add/remove/change data to a map. I am having some issues getting sci to load the file because I would like to use specter to navigate that map. The file loads in the load-fn function but when calling sci/eval-string with the {:load-fn load-fn} argument I get an error of

Caused by java.lang.Exception
   Could not require com.rpl.specter.

@patrick.farwick The issue is that your code probably somewhere does (require '[com.rpl.specter]) and sci tries to find that namespace but it can't find it in the options you gave it.

@patrick.farwick If you want this to work you'll have to provide those functions with {:namespaces {'com.rpl.specter {'select select}}}

:bindings is just a shorthand for {:namespaces {'user ...}}

I’m still having fun playing with sci as a way to run rewrite-cljc tests over a natively compiled rewrite-cljc lib. I’ve had some small successes, but am now wondering if/how this will work for parts of the rewrite-cljc API that are macros.

sci can do macros 🙂

@lee you can try (sci.core/copy-var 'some-macro rewrite-clj/some-macro (sci.core/create-ns 'some-ns nil)) https://borkdude.github.io/sci/doc/codox/sci.core.html#var-copy-var

Oh. Ok! Thanks for the pointer, I shall give it a try!

Hey @borkdude, I appreciate the help (I am pretty positive you answered my github actions / circleci question as well 🙂 ) Would you expect

(sci/eval-string "(require '[com.rpl.specter]) (select [:a] {:a 1 :b 2})" {:namespaces {'com.rpl.specter {'select select}}})

CompilerException java.lang.RuntimeException: Unable to resolve symbol: select in this context, compiling:

I wasn't completely done typing that but slack decided I was 😐

if you get a compiler exception, then it's happening before sci even sees it

so a regular Clojure error in your program probably

so my thought process after that was, okay, maybe even in the namespaces section it still needed {'select sr/select} because specter is also included in the file I was calling this from, but get the error:

CompilerException java.lang.RuntimeException: Can't take value of a macro: #'com.rpl.specter/select, compiling:

@patrick.farwick See the comment I just made to lread: try sci.core/copy-var

Okay let me try that

Success with copy-var on macro, thanks @borkdude! Although I had to copy from the original macro and not the potemkin copy. I’ll dig into why that’s the case later.

good to hear! I am still struggling a bit to get this to work but I think some of the nuances around this are alluding me

Like this kind of works:

(sci/eval-string "(require '[edit :as e]) (e/select [:a] {:a 1 :b 2}))" {:namespaces {'edit {'select (sci/copy-var sr/select (sci/create-ns 'edit nil))}}})

ExceptionInfo Could not resolve symbol: com.rpl.specter.impl/compiled-select* [at line , column ]  clojure.core/ex-info (core.clj:4739)

@patrick.farwick A macro is simply a function transforming an s-expression into another s-expression. If the resulting s-expression calls compiled-select* then you'll also need to include that

@patrick.farwick Maybe it helps if you include select as a function? (fn [x] (select x))

I'm not familiar with that API, but if you do it like that, the expansion happens outside of sci. However, select won't be a macro anymore

Hmm. I see what you are saying about the macro / s-expression piece. I am not totally sure what you mean by including select as a function. There isnt a particular need for select to be a macro. I just thought it was the only way to get specter's select into the sci eval string

What I mean is, you can try to lift the macro in a function, like in:

user=> (map #(when % %) [nil false 2 3 4])
(nil nil 2 3 4)

whereas (map when ...) doesn't work

@patrick.farwick You might be able to do something with ns-publics and copy-var

Yeah, I was kind of thinking about that. So maybe more of a #beginners question (but to be fair I am kind of a beginner 🙂 ), the functionality of sci is to contain the code that is being run outside of your core program right? I was toying around with just (load-file "edits.clj") into (vals (ns-publics 'edit)) and that seemed to get me the functions that I was looking for. I mean this whole process kind of revolves around RCE but maybe sci contains some of it? I do really appreciate the time and effort you put into helping.

What's RCE?

remote code execution

which, it is an internal tool pulling from a file in a location i expect, but i was thinking more of "good software engineering practices"

I'm not sure what exactly you are looking for, but the principle around which sci is built: it doesn't execute anything other than you give it, unless it's a pure function from clojure core which doesn't have noticable effects on the outside world.

So if you want to make it dangerous, you can, but by default it should be relatively harmless to execute random code

Yes. exactly. that makes sense.

For inspiration you can also look at the other projects that are using sci. The "biggest" one is probably babashka.

These projects are listed in the README of sci

Yeah, I was looking through a few of them last night along with just searching for projects that included sci across github but was a bit stuck still

I think my trouble has to do with the fact the "dangerous" piece i need to import is effectively a whole library.

@patrick.farwick babashka has imported several whole libraries

so has bootleg, spire.

it takes work, but doable.

Okay, let me check again and try to understand what is going on better

Okay, Well I think i found the couple of examples. I am trying to wrap my head around them in order to give it another try lol