Clojurians Log v2
beginners
Hi, everyone! Is there some debugging trick/lib to get evaluation output on each step of a threading macro?
You can inspect any particular step in (-> ...) with (doto prn) or something like that. And with (#(doto % prn)) in (->> ...).
And if you want to inspect every single step, there are multiple libraries with suitable functionality, e.g. https://github.com/philoskim/debux?tab=readme-ov-file#debugging-the-thread-macro-or.
Also, writing a macro that works like -> or ->> but adds a debugging tap>/`prn` line in between each step is very easy and a nice macros-writing exercise if you feel like it.
Aha, debux that's the one. Thank you!
Will follow your advice on macro exercise)
Just a tiny hint - I'd make that macro itself emit code that uses ->. No need to repeat work that -> already does for you.
@yaro there is also https://www.flow-storm.org/, which will allow you to see that and much more
I have been meaning to have a look at it for ages now, but I really hate to get out of nvim
I comment #_ out the expressions in the code that I don't want to include in the result
https://youtu.be/XM8ymzlHRdQ?si=AidR26wVgo4H3Cs1
Or Emacs cider debug tool will step through an expression, form by form, showing the current values.
Its a very good tool, especially for recursive code
https://www.youtube.com/live/pyIbP4BOGpQ?si=MnmfdYChxQp75bMd&t=1145
Hi everyone! I know that when we transform strings into symbols (for example (symbol "+")) the generated symbol is not bound to the + function of the core lib. However. If I ran the following, the result is 1, what is the reason for this behavior? I ran some tests, and looks like the call is always returning the last number in the function call.
((symbol "+") 1 1)
Symbols as objects are invokable and work in the same exact way as keywords - they look themselves up in an associative data structure.
user=> (def m {'a 1})
#'user/m
user=> ((symbol "a") m)
1[map key not-found] arity of get is used, so the first 1 is map, the symbol itself is key, and the second 1 is not-found.
1 is not associative, it can have no keys, so the not-found value is returned:
user=> ((symbol "+") 1 :not-found)
:not-foundSo, in my snippet, it is "searching" for the symbol + inside the first 1, and since it is not found, it returns the second 1, am I correct?
Yep!
Thank you for the information!
Is there any map containing all functions of the core lib?
Of course, (ns-publics 'clojure.core).
In case you're asking about the map of functions because you're trying to bind the symbol from a string to the actual function, take a look at resolve or ns-resolve
Oh, and in that case - requiring-resolve. Because ns-resolve won't work when the target ns isn't loaded.