Why are the keywords written with a quote?
> (keywords '(useless microframework academic swag))
Shouldn't it be a list with strings or something? What if the keywords were complex structures not just strings?
S-expressions
11–20 of 46 posts
Re: S-expressions
#12Was the use of dict and list necessary? This is an actual question, not a rhetorical criticism. I have recently been trying to learn common lisp.
Using dict and list here preserves the dynamic nature of JSON. If you have some sort of schema - which in reality you probably would have, even using JSON - that implies dict and list you wouldn't need to use those.
Re: S-expressions
#13Why are the keywords written with a quote? > (keywords '(useless microframework academic swag)) Shouldn't it be a list with strings or something? What if the keywords were complex structures not just strings?
if it's not quoted the list will be treated as an expression, and evaluate "Useless", which is probably not what you want.
Re: S-expressions
#14> Side note: Wouldn't it be awesome if composer supported composer.sexpr files natively, so that we would no longer have to write JSON? No, not really.
Why the quick dismissal? I find s-expressions much easier to work with than JSON.
Re: S-expressions
#15Why are the keywords written with a quote? > (keywords '(useless microframework academic swag)) Shouldn't it be a list with strings or something? What if the keywords were complex structures not just strings?
if it's not quoted the list will be treated as an expression, and evaluate "Useless", which is probably not what you want.
Right so instead you'd write: keywords (list "a" "b") ? Which would let you also do complex things like (list (person "bob") ...)
Re: S-expressions
#16Parsing S-expressions is easy: Dijkstra solved it in a really nice way with the Shunting Yard Algorithm.
I thought that was for infix expressions with order
of operations?
Re: S-expressions
#17Why are the keywords written with a quote? > (keywords '(useless microframework academic swag)) Shouldn't it be a list with strings or something? What if the keywords were complex structures not just strings?
The only Lisp I know is Racket (basically Scheme), so take the following with a grain of salt.
'(foo bar baz) is almost the same thing as (list foo bar baz). However, ' also makes the contents of the list into symbols, not variable references. Basically, '(foo bar baz) returns (list 'foo 'bar 'baz), not a list containing the values of the variables foo, bar, and baz.
Symbols aren't much like strings. They're immutable, and actually just refer to a unique number, not characters. I hope that sort of makes sense!
Re: S-expressions
#18Earlier quoted context omitted.
if it's not quoted the list will be treated as an expression, and evaluate "Useless", which is probably not what you want.
Right so instead you'd write: keywords (list "a" "b") ? Which would let you also do complex things like (list (person "bob") ...)
[deleted]
Re: S-expressions
#19Was the use of dict and list necessary? This is an actual question, not a rhetorical criticism. I have recently been trying to learn common lisp.
It is if you want to differentiate between a list of lists and a map. Maps are not natively supported in s-expressions.
So there is a need to create a sub-language to handle special data structures.
I have done this as well. But I use a special namespace '#dict' for example. So it would be
(#dict (k1 v1) (k2 v2))
Another way of doing it is using a flat list and just using an alternation with keys being prefixed by some special character:
(:k1 v1 :k2 v2)
Re: S-expressions
#20> Side note: Wouldn't it be awesome if composer supported composer.sexpr files natively, so that we would no longer have to write JSON?
If you, too, think this would be awesome, check out extensible data notation: https://github.com/edn-format/edn.