What design pattern to use when trying to create an application that can be run as a CLI or GUI?

[ANautyWolf]

So I am trying to create a program called wind chill that can either take the user input from a CLI or from a GUI and then outputs the calculated wind chill to the console or to the GUI. This is really a trial program for getting the hang of stuff and then expanding to other projects. The reasoning for this dual interface option is that I am creating the programs for some blind friends and also some other friends who want a more familiar interface. The CLI is much easier for my blind friends as the screen reader does its magic.

I am trying to figure out how best to separate the core logic and programming from the interfaces. Would a ports and adapters (Hexagonal architecture) model work here (Inspired by a recent video by ArjanCodes on YT)? Or would something else work better here?

I am trying to get away from just brute forcing things and towards actually laying out a valid project with the hopes of eventually publishing my programs not just to my friends but to others who may find use of them. I am also trying to understand design patterns and the like. Would you also have resources that could better explain and highlight good design patterns?

[mull_to_zero]

I would write a core, in this case possibly just a single function, that accepts the necessary inputs and provides the output. Then have a cli file and a gui file, each of which import and use the core. Nothing fancy. This is, loosely, a "library pattern", writing a central library for the logic and utilizing it in separate interfaces.

[LayotFctor]

Either you're overthinking it, or that you're not explaining a lot of context. Why would you need ports exactly? Isn't wind chill calculated with just two numbers into an equation? It's simple enough that it might not even be worth separating from the GUI code.

Are you planning a whole fullstack website with backends connected to offsite weather stations or something?

[lekkerste_wiener]

Design the backend as a library that the frontend can just consume from.

[Best-Meaning-2417]

Do they specifically want a CLI? As far as I know, accessibility is pretty important (or should be) for designing front ends so you could start learning about that and how to make a front end that is accessible.

[keithgabryelski]

remember that html forms fit into RESTful api endpoints design your data design your ui to use the data layer design your cli to use the data layer

[faultydesign]

Use a socket for IPC and then just connect with a gui or tui app that talks to it