How To Construct a Map Conditionally in Clojure

 Posted on 2025-01-05  |  1 minutes  |  190 words

I was wondering how to construct a multi-key map conditionally while I was coding in Clojure. Ideally, I would like to build it "in one pass" like {:bar 2 (when true :baz 3)}, but from what I had collected from Blue Sky, it seemed that's impossible, or it's just not an idiomatic way to program like that in Clojure. (Or, is this just a side effect of writing too much imperative code? [Read More]
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A Few Quick Notes About babashka/fs

 Posted on 2024-12-07  (Last modified on 2024-12-19)  |  1 minutes  |  149 words

Recently I've used babashka/fs a little bit, here are some quick notes for it: Path vs File. Use Path whenever possible, according to this SO answer to "Java: Path vs File". This is actually Java related. It's ok to use a path as a key for a clojure map. At my first try, I somehow came to the conclusion that it's not ok, while I was refactoring the live reload for clay. [Read More]
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Doing Unit test in Clojure Is Easy

 Posted on 2024-11-28  (Last modified on 2024-12-07)  |  1 minutes  |  165 words

While refactoring the live reload feature of Clay, I realized I'd better break long functions into smaller and functional ones (as many as I can), which is also a common practice in the clojure community. Small pure functions not only are easy to verify on the development process (using a REPL), but also are easy to test. And unit tests are easy to write in clojure, just use deftest from clojure. [Read More]
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Adding Clojure Dependencies from the Command Line

 Posted on 2024-11-09  (Last modified on 2024-11-10)  |  1 minutes  |  84 words

While debugging a live reload issue of Clay a few days ago, I learned from Markus Agwin that we can actually add dependencies on the fly from the command line, just like this: clj -Sdeps "{:deps {org.scicloj/clay {:mvn/version \"2-beta21\"}}}". Even better, we can add dependency from a Git repo and specify the commit hash: clj -Sdeps "{:deps {io.github.scicloj/clay {:git/url \"https://github.com/scicloj/clay.git\" :git/sha \"35a46541db66ae6b4e1af628b7c24c42d3be418f\"}}}", which is really helpful for experimenting and verifying things. [Read More]
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Bitten by Lazy Sequence of map

 Posted on 2024-11-09  (Last modified on 2024-11-10)  |  1 minutes  |  167 words

While impletenting the live reload feature for Clay a few weeks ago, unfortunately, I was bitten by the laziness of map. It seems quite obvious we all know that its result is a lazy sequence, but I just can't help fall into the "trap". At that time I was adding a vector to keep track of all beholder instances watching file changes in user specified directories. So then when it's time to stop all the watchers, I used something like to achieve the goal: [Read More]
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Anonymous Functions in Thread Macros

 Posted on 2024-11-08  (Last modified on 2024-11-10)  |  1 minutes  |  194 words

While adding the live reload feature to Clay, I encountered a problem of applying anonymous functions to thread macros. For example, below is a simple snippet trying to wrap the input directory as a vector with the help of thread macro, but surprisingly, it errors out. After some searching, I figured out that I need to put the anonymous function into another pair of parentheses: (-> "/tmp/" #(if (vector? %) % [%])) ;; => Syntax error (ClassCastException) compiling fn* at (simple4all. [Read More]
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Start a Clojure nREPL in the Command Line for Cider

 Posted on 2024-11-08  (Last modified on 2024-11-12)  |  1 minutes  |  174 words

While troubleshooting and fixing a live reload bug in Clay today, which requires to start a minimal Clojure environment, I figured out how to start a nREPL from the command line. Instead of using M-x cider-jack-in-clj directly from Emacs, actually we can manully bring up an nREPL with this: clj -Sdeps "{:deps {org.scicloj/clay {:mvn/version \"2-beta21\"} cider/cider-nrepl {:mvn/version \"0.50.2\"}}}" -m nrepl.cmdline --middleware "[cider.nrepl/cider-middleware]" (The clay part is only necessary for this debugging), and then connect to this nREPL using the Emacs command M-x cider-connect-clj. [Read More]
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