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I don’t consider myself a Lisp wizard and mostly stick to pretty simple code but to name a few cool things that would have been tedious or impossible in another

I don’t consider myself a Lisp wizard and mostly stick to pretty simple code but to name a few cool things that would have been tedious or impossible in another language: - A desktop application for a bank in which not only the gui’s content but the look and structure was generated or changed on the fly mimicking the status of a database. - An interpreter in which most of its classes and methods were automatically generated. The Java rewrite took pretty nasty code generation hacks, visitor pattern madness and way more LOC. - Some program with a huge cache (glorified hash table) that was not catching simple strings or objects as keys but actual code as s-expressions. I always thought that was pretty cool. Most if not all of my Lisp (and Perl) projects have been eventually rewritten in Java, and not exactly due to technical issues. I mostly put up with Go these days which is great most of the time but of course makes me yearn for a more powerful language or wished I never dabbled with those.

mbrodersen 5y ago
I have implemented pretty much all of that in C++. It wasn’t hard or tedious. Using declarative data structure to runtime generate the UI from (for example) is something I do all the time. In C++, C# and Typescript. And evaluating expressions at runtime is just using an AST. Something I have also done a lot.
- TurboHaskal 5y ago
  The GUI application was particularly elegant because the program would detect the changes in the database, change the class structure and attributes of screens and widgets at runtime with all runtime instances being updated. Note that this was written decades ago, way before people got excited at Swift UI, Qt QML or Javascript web apps. As for "just using AST", it is tedious to me, that's why I don't bother with it in other languages, and judging by the code that I've seen, it is for the average programmer as well.
  - mbrodersen 5y ago
    Yep nothing that I haven’t done in other languages. I learned Typescript and wrote a 52 page business application from scratch in a few months using the declarative approach. I used JSON to declare everything the same way you would declare it in Lisp and had all the same advantages. Parsing JSON in Typescript is a single line of code. The same as calling read in Lisp. And a college of mine took the application and easily made a version for another customer in less than a day. Changing most of the 52 pages to match the other customer. The look, the page layout, some of the logic etc. He never looked at the source code. And mind you I have written my own Lisp dialects just for fun, and have written code in Common Lisp and Scheme. I like the simplicity of Lisp the same way that I like the simplicity of Forth. But I just prefer other languages. Not having types is tedious to me.
    - TurboHaskal 5y ago
      That's really cool, but you should then be aware that what you are describing is a subset of what homoiconic languages offer as "data is code". Some time ago I wrote a sort of DevOps tool in Python (because I know better than to start new projects in Lisp in most settings). This tool had preconfigured tasks defined as point-free style functions that were easily composable. Non programmers were able to define their own pipelines either submitting a YAML file or dragging & dropping these components in a web UI. This was very powerful, but anything remotely complex (if you didn't want to end up reinventing Forth) required dropping down to Python to define these. JSON and YAML are very good at conveying structure, but fall sort for anything else. It would be like doing any sort of complex programming with Ansible via just using roles and playbooks. It's possible, but no one sane does. Now the question is if this really matters. Judging at the shape of the industry, the clear answer is no.
      - deleted 5y ago
        [deleted]
      - mbrodersen 5y ago
        Yep there are cool things you can do in Lisp that you can’t do in other languages. But, as you say, it doesn’t matter to most developers. What matters to most developers is a large language community, and a great selection of battle proven frameworks/libraries to make their job easy. Look at JavaScript going from the ugly duckling of languages that nobody use, to being absolutely essential to millions of programmers everywhere. Not because of the language, but because of the large community of developers forced to use JavaScript, resulting in a huge supply of frameworks and support/help available to JavaScript developers. If Lisp had been used instead of JavaScript, it might have been equally popular today. I personally would have preferred that actually.

mbrodersen 5y ago

I have implemented pretty much all of that in C++. It wasn’t hard or tedious. Using declarative data structure to runtime generate the UI from (for example) is something I do all the time. In C++, C# and Typescript. And evaluating expressions at runtime is just using an AST. Something I have also done a lot.

TurboHaskal 5y ago
The GUI application was particularly elegant because the program would detect the changes in the database, change the class structure and attributes of screens and widgets at runtime with all runtime instances being updated. Note that this was written decades ago, way before people got excited at Swift UI, Qt QML or Javascript web apps. As for "just using AST", it is tedious to me, that's why I don't bother with it in other languages, and judging by the code that I've seen, it is for the average programmer as well.
- mbrodersen 5y ago
  Yep nothing that I haven’t done in other languages. I learned Typescript and wrote a 52 page business application from scratch in a few months using the declarative approach. I used JSON to declare everything the same way you would declare it in Lisp and had all the same advantages. Parsing JSON in Typescript is a single line of code. The same as calling read in Lisp. And a college of mine took the application and easily made a version for another customer in less than a day. Changing most of the 52 pages to match the other customer. The look, the page layout, some of the logic etc. He never looked at the source code. And mind you I have written my own Lisp dialects just for fun, and have written code in Common Lisp and Scheme. I like the simplicity of Lisp the same way that I like the simplicity of Forth. But I just prefer other languages. Not having types is tedious to me.
  - TurboHaskal 5y ago
    That's really cool, but you should then be aware that what you are describing is a subset of what homoiconic languages offer as "data is code". Some time ago I wrote a sort of DevOps tool in Python (because I know better than to start new projects in Lisp in most settings). This tool had preconfigured tasks defined as point-free style functions that were easily composable. Non programmers were able to define their own pipelines either submitting a YAML file or dragging & dropping these components in a web UI. This was very powerful, but anything remotely complex (if you didn't want to end up reinventing Forth) required dropping down to Python to define these. JSON and YAML are very good at conveying structure, but fall sort for anything else. It would be like doing any sort of complex programming with Ansible via just using roles and playbooks. It's possible, but no one sane does. Now the question is if this really matters. Judging at the shape of the industry, the clear answer is no.
    - deleted 5y ago
      [deleted]
    - mbrodersen 5y ago
      Yep there are cool things you can do in Lisp that you can’t do in other languages. But, as you say, it doesn’t matter to most developers. What matters to most developers is a large language community, and a great selection of battle proven frameworks/libraries to make their job easy. Look at JavaScript going from the ugly duckling of languages that nobody use, to being absolutely essential to millions of programmers everywhere. Not because of the language, but because of the large community of developers forced to use JavaScript, resulting in a huge supply of frameworks and support/help available to JavaScript developers. If Lisp had been used instead of JavaScript, it might have been equally popular today. I personally would have preferred that actually.