In a recent post I spoke about abandoning a previous project that had gone off the rails, and I've been doing more work in Common Lisp, and I wanted to report a bit more, with some recent developments. There's a lot of writing about learning to program for the first time, and a fair amount of writing about lisp itself, neither are particularly relevant to me, and I suspect there may be others who might find themselves in a similar position in the future.
My Starting Point
I already know how to program, and have a decent understanding of how to build and connect software components. I've been writing a lot of Go (Lang) for the last 4 years, and wrote rather a lot of Python before that. I'm an emacs user, and I use a Common Lisp window manager, so I've always found myself writing little bits of lisp here and there, but it never quite felt like I could do anything of consequence in Lisp, despite thinking that Lisp is really cool and that I wanted to write more.
My goals and rational are reasonably simple:
- I'm always building little tools to support the way that I use computers, nothing is particularly complex, but it'd enjoy being able to do this in CL rather than in other languages, mostly because I think it'd be nice to not do that in the same languages that I work in professionally. 
- Common Lisp is really cool, and I think it'd be good if it were more widely used, and I think by writing more of it and writing posts like this is probably the best way to make that happen.
- Learning new things is always good, and I think having a personal project to learn something new will be a good way of stretching my self as a developer. Most of my development as a programmer has focused on
- Common Lisp has a bunch of features that I really like in a programming language: real threads, easy to run/produce static binaries, (almost) reasonable encapsulation/isolation features.
Knowing how to program makes learning how to program easier: broadly speaking programming languages are similar to each other, and if you have a good model for the kinds of constructs and abstractions that are common in software, then learning a new language is just about learning the new syntax and learning a bit more about new idioms and figuring out how different language features can make it easier to solve problems that have been difficult in other languages.
In a lot of ways, if you already feel confident and fluent in a programming language, learning a second language, is really about teaching yourself how to learn a new language, which you can then apply to all future languages as needed.
Except realistically, "third languages" aren't super common: it's hard to get to the same level of fluency that you have with earlier languages, and often we learn "third-and-later" languages are learned in the context of some existing code base or project4, so it's hard to generalize our familiarity outside of that context.
It's also the case that it's often pretty easy to learn a language enough to be able to perform common or familiar tasks, but fluency is hard, particularly in different idioms. Using CL as an excuse to do kinds of programming that I have more limited experience with: web programming, GUI programming, using different kinds of databases.
My usual method for learning a new programming language is to write a program of moderate complexity and size but in a problem space that I know pretty well. This makes it possible to gain familiarity, and map concepts that I understand to new concepts, while working on a well understood project. In short, I'm left to focus exclusively on "how do I do this?" type-problems and not "is this possible," or "what should I do?" type-problems.
The more I think about it, the more I realize that when we talk about "knowing a programming language," inevitably linked to a specific kind of programming: the kind of Lisp that I've been writing has skewed toward the object oriented end of the lisp spectrum with less functional bits than perhaps average. I'm also still a bit green when it comes to macros.
There are kinds of programs that I don't really have much experience writing:
- GUI things,
- the front-half of the web stack, 
- processing/working with ASTs, (lint tools, etc.)
- lower-level kind of runtime implementation.
There's lots of new things to learn, and new areas to explore!
|||Because it's 2020, I've done a lot of work on "web apps," but most of my work has been focused on areas of applications including including data layer, application architecture, and core business logic, and reliability/observability areas, and less with anything material to rendering web-pages. Most projects have a lot of work to be done, and I have no real regrets, but it does mean there's plenty to learn. I wrote an earlier post about the problems of the concept of "full-stack engineering" which feels relevant.|