6 ms·

Not everything that can be represented with s-expressions is a lisp. For example: (html (body (h1 "Hello, World!"))) This does not mean that HTML

Not everything that can be represented with s-expressions is a lisp. For example: (html (body (h1 "Hello, World!"))) This does not mean that HTML is a lisp.

anthk 2y ago
Well: This webserver in Maclisp http://up.dfupdate.se/httpd%20html http://up.dfupdate.se/httpd%20html gave birth to this: http://up.dfupdate.se/ulml.html http://up.dfupdate.se/ulml.html
anthk 2y ago
Also, more than Lisp, clips would be a really good choice there. Defining constraints to configure a system? That's basically what literally Clips does. https://www.clipsrules.net/ https://www.clipsrules.net/
cess11 2y ago
OK, but what about the homoiconicity and syntax macros?
- axblount 2y ago
  I don't know Ansible well enough to say for sure, but the macro example seems like more of a C preprocessor style "macro." I don't see how it's doing anything more than filling in a template.
  - cess11 2y ago
    It's executed at runtime, not before some compilation stage.
- simplify 2y ago
  "What is homoiconicity then? Typical definitions state that it is simply “code as data”, will point to a relationship between a program’s structure and syntax or note that the program source is expressed in a primitive data-type of the language. In the below, we will show that none of these definitions make much sense." https://www.expressionsofchange.org/dont-say-homoiconic/ https://www.expressionsofchange.org/dont-say-homoiconic/
  - cess11 2y ago
    In this context it seems to refer to programming in a language where the developer facing code is represented in terms of data structure literals within the language. It's a reasonable understanding of what is usually meant in a Lisp-like setting. The code is a list, so you can trivially construct and deconstruct executable lists, just like you can trivially construct data carrying lists. One could make clever quips that this isn't enough, you need quote/unquote as well to make it practical, and is that really implied by homoiconicity? Should we really use this word? Maybe we should pay someone to make up a new one?
mepian 2y ago
I agree, recently I shared here a great article by Hayley Patton on this exact topic: https://gist.github.com/no-defun-allowed/4f0a06e17b3ce74c6aeac514281f350f https://gist.github.com/no-defun-allowed/4f0a06e17b3ce74c6ae...
saghm 2y ago
You'd think this would be more understood given that pretty much the whole point of lisp is to be pretty close to just representing an AST without relatively few frills. The idea that we can represent most languages with a tree-like structure isn't particularly novel.
jimbokun 2y ago
But that can be perfectly valid Lisp. Lisp libraries producing HTML often look just like that.
btilly 2y ago
Not all of HTML can be represented with s-expressions. The following is perfectly valid. Hello World! Greetings Earthlings!
- MathMonkeyMan 2y ago
 I never noticed that, though "doesn't require a closing tag" and "requires that there is no closing tag" ought to have been hints for me.
- LegionMammal978 2y ago
 And yet it's semantically identical to Hello World!</> Greetings Earthlings! You can see this by looking at the innerHTML, which is really just a serialized form of the DOM tree.
- ptx 2y ago
 Is it actually valid? W3C's HTML validator complains about invalid nesting. It might work because the HTML5 parsing algorithm produces well-defined results for broken HTML, but I'm not sure that's the same as "perfectly valid" – the spec calls such markup "misnested" and "erroneous" [0]. [0] https://html.spec.whatwg.org/#an-introduction-to-error-handling-and-strange-cases-in-the-parser https://html.spec.whatwg.org/#an-introduction-to-error-handl...
 - btilly 2y ago
 It certainly was valid according to the original specs. I first saw it as an example over 20 years ago in a debate about whether XHTML should replace HTML 4.0.

Not everything that can be represented with s-expressions is a lisp. For example: (html (body (h1 "Hello, World!"))) This does not mean that HTML is a lisp.

anthk 2y ago

Well: This webserver in Maclisp http://up.dfupdate.se/httpd%20html http://up.dfupdate.se/httpd%20html gave birth to this: http://up.dfupdate.se/ulml.html http://up.dfupdate.se/ulml.html

anthk 2y ago

Also, more than Lisp, clips would be a really good choice there. Defining constraints to configure a system? That's basically what literally Clips does. https://www.clipsrules.net/ https://www.clipsrules.net/

cess11 2y ago

OK, but what about the homoiconicity and syntax macros?

axblount 2y ago
I don't know Ansible well enough to say for sure, but the macro example seems like more of a C preprocessor style "macro." I don't see how it's doing anything more than filling in a template.
- cess11 2y ago
  It's executed at runtime, not before some compilation stage.
simplify 2y ago
"What is homoiconicity then? Typical definitions state that it is simply “code as data”, will point to a relationship between a program’s structure and syntax or note that the program source is expressed in a primitive data-type of the language. In the below, we will show that none of these definitions make much sense." https://www.expressionsofchange.org/dont-say-homoiconic/ https://www.expressionsofchange.org/dont-say-homoiconic/
- cess11 2y ago
  In this context it seems to refer to programming in a language where the developer facing code is represented in terms of data structure literals within the language. It's a reasonable understanding of what is usually meant in a Lisp-like setting. The code is a list, so you can trivially construct and deconstruct executable lists, just like you can trivially construct data carrying lists. One could make clever quips that this isn't enough, you need quote/unquote as well to make it practical, and is that really implied by homoiconicity? Should we really use this word? Maybe we should pay someone to make up a new one?

mepian 2y ago

I agree, recently I shared here a great article by Hayley Patton on this exact topic: https://gist.github.com/no-defun-allowed/4f0a06e17b3ce74c6aeac514281f350f https://gist.github.com/no-defun-allowed/4f0a06e17b3ce74c6ae...

saghm 2y ago

You'd think this would be more understood given that pretty much the whole point of lisp is to be pretty close to just representing an AST without relatively few frills. The idea that we can represent most languages with a tree-like structure isn't particularly novel.

jimbokun 2y ago

But that can be perfectly valid Lisp. Lisp libraries producing HTML often look just like that.

btilly 2y ago

Not all of HTML can be represented with s-expressions. The following is perfectly valid. Hello World! Greetings Earthlings!

MathMonkeyMan 2y ago
I never noticed that, though "doesn't require a closing tag" and "requires that there is no closing tag" ought to have been hints for me.
LegionMammal978 2y ago
And yet it's semantically identical to Hello World!</> Greetings Earthlings! You can see this by looking at the innerHTML, which is really just a serialized form of the DOM tree.
ptx 2y ago
Is it actually valid? W3C's HTML validator complains about invalid nesting. It might work because the HTML5 parsing algorithm produces well-defined results for broken HTML, but I'm not sure that's the same as "perfectly valid" – the spec calls such markup "misnested" and "erroneous" [0]. [0] https://html.spec.whatwg.org/#an-introduction-to-error-handling-and-strange-cases-in-the-parser https://html.spec.whatwg.org/#an-introduction-to-error-handl...
- btilly 2y ago
  It certainly was valid according to the original specs. I first saw it as an example over 20 years ago in a debate about whether XHTML should replace HTML 4.0.