Connection pooling is a technique for improving app performance. A pool (cache) of reusable connections is maintained meaning when users connect to the database they can reuse an existing connection. When the user finishes using the connection it is placed back in the pool for other users to use. This reduces the overhead of connecting to the database by decreasing network traffic, limiting the cost of creating new connections, and reducing the load on the garbage collector. Effectively improving the responsiveness of your app for any task that requires connecting to the database.
Clojure 1.10 introduced a new system called tap. From the release notes: tap is a shared, globally accessible system for distributing a series of informational or diagnostic values to a set of (presumably effectful) handler functions. It can be used as a better debug prn, or for facilities like logging etc.
Sometimes web responses contain an unordered sequence of items along with a separate manifest that specifies the ordering. This article will cover how you can write a function to sort the list of items by the manifest order as well as using Clojure Spec to generate test data to verify its output.
Sometimes you want to make a user's experience feel more personal. An easy way to achieve this is by personalising text based content. For example in a text base adventure game you could replace placeholders in the text with information relevant to that particular player such as their name or class. This could help make your game more engaging.
Inconsistent case is a problems that tends to come up at application boundaries in your software stack. For example your Clojure codebase might use kebab-case for keywords, whilst your database uses snake_case for column names and your client wants camelCase in its json responses. Often, conventions and/or technical limitations prevent you from simply having a single case throughout your entire stack.
Checking for containment, whether a collection contains an item, is a common task in software development. This post covers the ways you can check for containment in Clojure.
Sorting collections of items is something that comes up frequently in software development. This post covers the multitude of ways you can sort things in Clojure.
The Lisp family of languages is relatively new to me. I learned both Clojure and Emacs Lisp at the same time, as Emacs is a popular Clojure editor. Learning these two lisps side by side has made me wonder about the subtle differences between the two, in particular how they approach passing functions as arguments to other functions (first class functions). It turns out this boils down to Clojure being a lisp-1 and Emacs Lisp a lisp-2.
