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Why Lisp?

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Re: Why Lisp?

#71

Post by Dewie3 »

kazinator wrote: post #25
IshKebab wrote: post #16

Earlier quoted context omitted.

On the other hand, this really hurts readability. When reading other people's code you now effectively have to learn what "language" they use too. I'd say it's probably worth that cost, if used judiciously.

"If used judiciously" is just FUD. Soviet-era authority figure: "Western-style freedom has its good points---if applied judiciously". If you're a proper Lisper, you use macros like it's going out of style, and other proper Lispers love your code for it. All programs have their own dictionary of whatever it is they define, whether it be macros or variables. You can no more understand a function call just by looking at…

I guess the "problem" with understanding this perspective for us non-lisp people is that we may not be able to imagine all the places that we could have used macros (or something equivalent) if we haven't even learnt it. You don't know what you don't know, or in this case, you don't know how to use something you haven't used. But this seems to be the same for boatload of programming features that many people aren't taught with their first language, but rather later - higher order functions, lazy evaluation/generators/etc., type-level functions... we might at first think "this is a special tool only to be used in certain circumstances/only to be used by wizards". And then it might turn out that they are useful all the damn time.

The net result, at least for me, is that I get spoiled and then it is hard for me to go back 'more primitive ways'. :)

Re: Why Lisp?

#72

Post by GFK_of_xmaspast »

WalterGR wrote: post #12

The article doesn't discuss macros, which is one of the answers to "Why Lisp?" I didn't "get" macros until I read a footnote in the (freely available) book Practical Common Lisp . In chapter 7, it introduces the `dolist` macro. DOLIST loops across the items of a list, executing the loop body with a variable holding the successive items of the list. This is the basic skeleton (leaving out some of the more esoteric opt…

It's kind of cool how in lisp you're supposed to do macros to change major aspects of how the language behaves, but in C if you try having a little bit of fun with #define and the pre-processor everybody starts getting just extremely rude at you.

Re: Why Lisp?

#73

Post by GFK_of_xmaspast »

kazinator wrote: post #29
don_draper wrote: post #20

Earlier quoted context omitted.

It would help if I saw a real world problem and how you can solve it Lisp and not in say Python.

Any real world problem solved in Lisp, relative to being solved in Python, eliminates the superfluous problem of Python being involved: a syntactically Fortran-like cumbersome scripting language with somewhat Lispy semantics. Note that you can program the CL system by expressing yourself in Python: https://common-lisp.net/project/clpython/ Common Lisp is not only a language, but also a platform (analogous to Mono or…

So your answer is 'I have no such example' ?

Re: Why Lisp?

#74

Post by stephengillie »

WalterGR wrote: post #12

The article doesn't discuss macros, which is one of the answers to "Why Lisp?" I didn't "get" macros until I read a footnote in the (freely available) book Practical Common Lisp . In chapter 7, it introduces the `dolist` macro. DOLIST loops across the items of a list, executing the loop body with a variable holding the successive items of the list. This is the basic skeleton (leaving out some of the more esoteric opt…

I'm sorry for asking a dumb question; I'm a sysadmin not a software developer:

Is this similar to needing a dozen nearly-identical lines of code, writing one, then using Excel to manipulate the other 11 lines into what you want, then copying it back (and cleaning tabs in the process)?

Essentially programmatically writing the program - is that what Lisp's macros are?

Re: Why Lisp?

#75

Post by gknoy »

don_draper wrote: post #20
WalterGR wrote: post #12

The article doesn't discuss macros, which is one of the answers to "Why Lisp?" I didn't "get" macros until I read a footnote in the (freely available) book Practical Common Lisp . In chapter 7, it introduces the `dolist` macro. DOLIST loops across the items of a list, executing the loop body with a variable holding the successive items of the list. This is the basic skeleton (leaving out some of the more esoteric opt…

It would help if I saw a real world problem and how you can solve it Lisp and not in say Python.

I don't think there are very many "real world" problems that you CAN solve in Lisp, and CANNOT solve in Python. Anything [0] you can write in Python, you can likely solve in Lisp, probably in similar line count (without macros).

One thing I __really__ miss from working in lisp is the idea that I can reload things in the repl. In Python, once I've imported something, I can't really redefine it without pasting in the definition, which makes iterating on a class definition much harder. In Lisp, I can hit a key in my editor and the running REPL gets the new definition, and I can start working with it (or rewriting tests, etc).

The power of the REPL in lisp is __amazing__. I love me some IPython (it's awesome), but there just isn't the same tight integration between that and a running system. The "default" Python likely has all the tools you need to do that, but it just isn't presented as the Way you Do It.

Django's auto-reload when code changes is an example of this. The trouble is, I can't get to a REPL easily within that, without invoking ipdb. I don't know how to integrate my editor with the Python process in a similar way, etc.

All that said, I still love coding in Python. Hy makes me excited, but then I just started writing python-with-parens and wasn't sure what I had gained. :)

0: I'm sure there is someone who can give a counterexample, but I cannot thnk of any.

Re: Why Lisp?

#76

Post by jlarocco »

vog wrote: post #69
platz wrote: post #52

Earlier quoted context omitted.

I wonder how much macros are necessary one you add call-by-name parameters e.g. scala.

Or, once you have lazy evaluation (like in Haskell), for that matter.

Laziness can achieve a similar thing in that case (less elegantly, IMO), but there are other uses for macros that can't be solved with laziness.

Re: Why Lisp?

#77

Post by bliti »

stephengillie wrote: post #74
WalterGR wrote: post #12

The article doesn't discuss macros, which is one of the answers to "Why Lisp?" I didn't "get" macros until I read a footnote in the (freely available) book Practical Common Lisp . In chapter 7, it introduces the `dolist` macro. DOLIST loops across the items of a list, executing the loop body with a variable holding the successive items of the list. This is the basic skeleton (leaving out some of the more esoteric opt…

I'm sorry for asking a dumb question; I'm a sysadmin not a software developer: Is this similar to needing a dozen nearly-identical lines of code, writing one, then using Excel to manipulate the other 11 lines into what you want, then copying it back (and cleaning tabs in the process)? Essentially programmatically writing the program - is that what Lisp's macros are?

More or less. It allows you to write generic code you can reuse. In this case, you are extending the language. Feel free to post these "dumb" questions, or send them my way.

Re: Why Lisp?

#78

Post by eatonphil »

chaoky wrote: post #53
Xophmeister wrote: post #26

Earlier quoted context omitted.

Could someone please explain the difference between Lisp macros and, say, languages that have first-class functions? I get that a Lisp macro will be expanded into the respective code, while a function's execution is different. However, at the practical (i.e., developer's) level, are there any additional benefits? Can, say, a Lisp macro be 'partially formed', in the sense that it can expand into some boilerplate that…

A higher order function doesn't serve the same purpose as a macro. A higher order function is meant to be applied, called, composed etc. A lisp macro is a different type of abstraction. For example, many people think that macros are just hiding lambda's of higher order functions. This is wrong. A macro abstracts over implementation details of a construct to make it read naturally. For example, you can write a functio…

In what language are you writing?

Re: Why Lisp?

#79

Post by GFK_of_xmaspast »

kazinator wrote: post #39
swuecho wrote: post #22

Earlier quoted context omitted.

there is two sides. probably, one evil thing is you have to deal with every other's abstraction and it will make you frustrated when there is a large codebase and a deadline.

Let's see, what would I rather deal with. * Another programmer's 15 function API, and a document on how to use it properly? * Or another programmer's 15 function API, along with three macros which use the API properly, and capture all the scenarios I need based on a couple of examples.

How's this any different than taking a big ugly api and writing three shims around it to call it in the way you want?

Re: Why Lisp?

#80

Post by munificent »

> The reason that code represented as XML or JSON looks horrible is not because representing code as data is a bad idea, but because XML and JSON are badly designed serialization formats.

By that same token, a Volkswagen Beetle is a badly-designed boat.

XML was never designed as a data serialization format. It's a markup language. It was designed to sprinkle structure and metadata into large human-readable plaintext documents.

Likewise, JSON is a subset of a general-purpose programming language's literal notation that happened to be very fast to parse in a browser by virtue of the browser implementing that language.

Personally, I don't think s-exprs are a particularly great serialization format either. The problem is that there's no one-sized-fits-all for serialization. What we value is brevity, but basic information theory tells we can only make expressing some things more terse by making others more verbose.

When you say some format is badly-designed, all you're really saying is that it isn't optimized for the kinds of data you happen to want to serialize.

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