Clojurians Log v2
meander
hello - just starting to use meander and while I find it very impressive I still have no idea what I'm doing. Is there a way to group on an output variable? I have a map of route data that I would like to transform into a vector of route data. The results I get now work but they create a new route for each method instead of grouping everything under the path. Is this possible to do with meander?
(m/rewrites {:routes {"/test/:id" {:get {:request "..."
:response "..."}
:post {:request "..."
:response "..."}}
"/new/:id" {:get {:request "..."
:response "..."}
:post {:request "..."
:response "..."}}}}
{:routes {?route {?method {:request ?req-opts
:response ?res-opts}}}}
[?route {:conflicting true
?method ~(handler ?req-opts ?res-opts)}])
;; output looks like this:
(["/test/:id" {:get "..."}]
["/test/:id" {:post "..."}]
["/new/:id" {:get "..."}]
["/new/:id" {:post "..."}])
;; i'd like for it to look like this:
(["/test/:id" {:get "..." :post "..."}]
["/new/:id" {:get "..." :post "..."}])
You can use a memory variable to collect stuff (`!xs` ) but note in the case of rewrites you will want to us ~!xs if you want the vector itself (`search` might be a better choice here since your right-hand side intends to call a function anyway).
Memory variables also have broken semantics on the RHS for rewriting. 😄
how could I use memory variables in this case? I've tried using them on !route and !method but I still end up with 4 outputs, just with a bunch of single entity vectors:
([["/test/:id"] {:conflicting true, [:get] ...}]
[["/test/:id"] {:conflicting true, [:post] ...}]
...)
found this issue that seems to be the same problem - a lot of syntax I don't understand but might be able to reverse engineer it: https://github.com/noprompt/meander/discussions/222
FWIW/FYI: I haven't been supporting my Clojure libraries because my day-job is mostly Python. 🙂
Do you envision a meander-py being possible? working with a bunch of python devs right now who spend a LOT of time essentially writing json -> json ETLs that could easily be handled by meander.
Actually, one of the first things I did when I got into Python (had to because ML/AI) was implement the fundamental building blocks of a system like it. Of course, you don't have macros but you also don't technically need them.
I'm currently not doing much ETL so I haven't felt the need to really work on it. Python also has decent structural matching support nowadays. I use match a lot. And you can make simple rewrite rules with the pattern of
def some_rule[A, B](data: A) -> B:
match data:
case {"some_key": str() as some_str}:
...match is new in Python and many people don't use it or are not aware of it. Are the devs you know comfortable with Python's match? If not, that'd be a place to start with immediate benefits.All said, I recently had a few experiences where I wish I had something like Meander so I'll probably make time to build something eventually. For example, I built a prototype of single file components (SFCs) like Vue but for Python (because every Python templating language is some how horrible, and HTMX is fine for like 90% of the things you'd ever want to do on the front end). I think the compiler code would benefit from rewrite rules.
Personally, I've wanted to avoid doing open source work but I also feel like I don't want to keep these things to myself. The Python SFC thing has made me way more productive and I could see other people finding happiness using it. I just have to be up front with people about my time.
I'm also happy to just give people code and tell people what I know about how to build these things. At the core, what's driving Meander is pretty simple.
@noprompt Thank you for meander. Started using it this weekend to extract data from excel table. So good !