Is the Common Lisp 'loop' macro evil?

I must admit to being "old school" when it comes to Lisp coding. I like s-expressions. The loop macro introduces a non s-expression syntax to the language that I find a little uncomfortable. I spent 20 minutes this morning looking for interesting loop example uses and generally playing with them. Definitely some cool stuff, but I think that I will continue to pass on using the loop macro, except when it is already in other people's code - no point in rewriting stuff that works.

Different programming languages have different coding styles that seem to work well and are language specific. As an example, yesterday I wrote some Ruby code with two nested collection collect blocks. I had been coding non-stop in Common Lisp for weeks, and before I checked my new Ruby code into svn, I took another look at it: looked strange at first even though it was a natural Ruby coding style. I looked at it again this morning, after my "thinking in Lisp" mode was temporarily suspended, and the nested collect blocks looked just fine. Amazing how choice of programming language affects the way we think to solve problems.

Comments

  1. Pascal Costanza8:35 AM

    I can strongly recommend to read the chapter about LOOP in Peter Seibel's Practical Common Lisp. It is an exceptionally clear explanation how to construct LOOP expressions. Several people who also don't like LOOP use iterate instead which covers more or less the same ground, but is more complete, uses s-expressions throughout and is on top of that extensible.

    ReplyDelete
  2. Mark Watson, author and consultant8:58 AM

    Thanks Pascal. I just read Peter Seibel's chapter and took a quick look at iterate. If I spent close to 100% of my time coding in Common Lisp, then the loop macro would look better to me (as would iterate). I like concise code which is what loop and iterate are all about. However there is a limit to how many program language features that I can keep "ready at hand" and long term I spend roughly equal amounts of time developing in Lisp, Ruby, and Java. BTW, I find Ruby and Java easier to stay on top of, feature and coding tricks wise, but I prefer Lisp.

    I have considered giving up consulting and just doing product development to earn a living. If I ever do this (difficult because I enjoy consulting), there is almost a 100% probability that I would standardize on Common Lisp.

    ReplyDelete
  3. David Rupp11:53 AM

    Mark, can you give us some idea of where those jobs are (product development in Lisp), and what are the prospects for landing one? Maybe in a separate blog post?

    I'm getting back into Lisp, largely via Seibel's book, after a long layover in Java and (most recently) Ruby. Programming professionally in Lisp would be a refreshing change of pace.

    ReplyDelete
  4. Mark Watson, author and consultant12:22 PM

    Hello David,
    re: Lisp product development: that would be self funded, my taking a little risk hoping for a long tail of revenue. For Lisp programming jobs: I know that they are out there. My current customer just about insists that almost everything be done in Common Lisp. An idea: perhaps Lisp vendors like Franz and LispWorks might have leads on companies needing Lisp development talent.

    ReplyDelete
  5. Joe Marshall12:32 PM

    For what it is worth, I don't care for loop at all. I was going to paste my tirade here, but it occurs to me that I should blog my opinion of the LOOP macro and save it for posterity.

    ReplyDelete
  6. Mark Watson, author and consultant12:54 PM

    Hello Joseph: Good reasons for avoiding loop. The best reason may be the unpredictability of what the macro expansion is unless you either use loop a lot or use it in simple ways.

    ReplyDelete

Post a Comment

Popular posts from this blog

My Dad's work with Robert Oppenheimer and Edward Teller

Robert Oppenheimer and Edward Teller facilitated my Dad getting a professorship at UC Berkeley when I was 3 years old. Oppenheimer left Berkeley but Teller was a good friend of my father and I remember him being in our home. Three weeks ago, my wife and I were just leaving to see the new Oppenheimer movie when my Dad called. He mentioned that when I was in grade school he was invited to give a talk at Princeton. After his talk Oppenheimer talked with my Dad and invited him to have dinner at his house. My Dad said Oppenheimer was not well (I think he died of throat cancer soon afterwards) but his wife Kitty carried the conversation. My Dad, Ken Watson, passed away 10 days ago on August 18, 2023.
Read more

Time and Attention Fragmentation in Our Digital Lives

  As humans we have evolved over a few million years to be both attentive and reactive to danger, live in social communities, and spend much of our time being in the present moment gathering and eating food and socializing. The behavior of rapidly changing short attention to content on social media, too many good short form things to watch on streaming video entertainment platforms, are all rewiring our brains in an unnatural and unhealthy way. I fight back, but in really simple ways that entail little ceremony: Almost every morning I spend 30 minutes scanning Hacker News (about 10 minutes), Apple News (about 5 minutes), and the remaining time on Twitter and Mastodon finding interesting new (mostly tech) things. I make notes in a temporary Apple Note: links of things I may want to research, try, or simply read that day. I like to get this all done at once, and then not feel like I need to interrupt my activities during the day to “catch up” on what is happening in the world. In a w...
Read more

I am moving back to the Google platform, less excited by what Apple is offering

I have been been playing with the Apple Intelligence beta’s in iPadOS and macOS and while I like the direction Apple is heading I am getting more use from Google’s Gemini, both for general analysis of very large input contexts, as well as effective integration my content in Gmail, Google Calendar, and Google Docs. While I find the latest Pixel phone to be compelling, I will stick with Apple hardware since I don’t want to take the time to move my data and general workflow to a Pixel phone. The iPhone is the strongest lock-in that Apple has on me because of the time investment to change. The main reason I am feeling less interested in the Apple ecosystem and platform is that I believe that our present day work flows are intimately wrapped up with the effective use of LLMs, and it is crazy to limit oneself to just one or two vendors. I rely on running local models on Ollama, super fast APIs from Groq (I love Groq for running most of the better open weight models), and other APIs from Mist...
Read more