> (And yes, despite what the Common Lisp community has to say, Janet is a lisp, even if it’s not a Lisp)
I love this and understand both the sentiment expressed and (as a recovering member of the Cult Of Lisp) the reason why it was said.
I love this and understand both the sentiment expressed and (as a recovering member of the Cult Of Lisp) the reason why it was said.
The syntax and semantics are clearly similar to that of Lisps before it, and so is the feature set enabled by that very same syntax and the very same semantics. In that sense if Janet had to be the dialect of something else, I don't see what else but being a dialect of Lisp it could be.
And I don't think Janet is different enough in syntax and semantics to be given its own new family of language.
Anyways, those debate are kind of for fun and games, cause it doesn't really matter, but I think the description you could give to someone else who's asking: What's it like? And if you say, it's a bit like programming in any other Lisp, well you'd be giving them a pretty good idea of what it was like, unless they'd never programmed in any other Lisp either, then you're going to struggle, because there's not a whole lot like Lisp.
That said, I am not such a purist as to be bothered by it, and janet has a special place in my heart right along with chicken, racket, clojure and CL.
Lists in a conceptual sense are an ordered collection of heterogeneous elements with nestings.
In that sense, code in Janet is very much represented as such and processed as such. Which in my mind makes it a LISt Processing language :p
There is a specific minimal core of Lisp, which consists of a certain minimal set of data structures, operations and an evaluation mechanism.
An early version is described here:
https://dspace.mit.edu/bitstream/handle/1721.1/6096/AIM-008....
Another one is described here:
Cons/car/cdr are far less important, IMO, than eval.
Read, on the other hand, is also technically missing from Janet, and I personally don't mind a great deal, but I could see that being argued.
That's part of the core of the language.
Sure: Many other aspects from Lisp can be found also in Lisp-derived languages and other languages. Like all or some of runtime code loading, symbolic expressions, using symbolic expressions to encode source code, saving and starting heap images, garbage collection, managed memory, source level interpreters/debuggers, self-hosted compilers, read-eval-print-loops, macros, fexprs, integrated interactive development environments, ...
Even McCarthy's lisp had iterations of itself.
Personally, I think the second paper actually points to the essential component for me:
> LISP data are symbolic expressions that can be either atoms or lists. Atoms are strings of letters and digits and other characters not otherwise used in LISP. A list consists of a left parenthesis followed by zero or more atoms or lists separated by spaces and ending with a right parenthesis. The LISP programming language is defined by rules whereby certain LISP expressions have other LISP expressions as values.
I would use that to generalize to a family of languages like so:
""" A Lisp language consists of:
1) Some data representation which are symbolic expressions that can be either atoms or lists. Atoms are strings of letters and digits and other characters not otherwise used in the given Lisp language. A list consists of a starting character (commonly left parentheses) followed by zero or more atoms or lists separated by seperator characters (commonly spaces) and ending with a terminating character (commonly right parenthesis).
2) A programming language whose code uses that data representation and is defined by rules whereby certain Lisp expressions have other Lisp expressions as values. """
Personally I think that's the key aspect, the characteristics of what those rules are, and what the chosen characters are is what creates the family of language, they are the parameters you're allowed to change and must change for it to be a dialect and not just an alternate implementation of the same language.
Not even that. It's the programmatic definition of the core of Lisp. McCarthy's real Lisp implementation was much more featureful.
I would also think the Lisp program in the second paper is 'Lisp Program Zero'. ;-) If your language can run it, it is Lisp. The amount of modifications necessary (syntactic, operators, semantics, ...) gives an indication how far another language is away from it.
Here is a version in Common Lisp:
https://gist.github.com/lispm/d752d5761f7078de4041d4e453e70c...
Paren AST languages.
But this article has been sitting in a draft for the better part of a month, lol.