Add std/misc/walist

[fare]

Add a library for wrapped alists: alists in a box, such that the equality predicate is transported with the data, and, when stateful, the empty alist is properly handled.

Use walist to enable user-controled field order when printing json objects.

[vyzo]

Can we please separate the json stuff in different pr?
Or alternatively base this on the json-stdio branch and target that pr?

Merging this as is will create horrendous conflicts that we should avoid.

[vyzo]

I would suggest the following hierarchy:

walist ; equal?
(walistq walist) ; eq?
(walistv walist) ; eqv?
walist! ; mutable, disjoing from immutables
(walistq! walist!) ; mutable eq?
(walistv! walist!) ; mutable eqv?

And then you can write a macro that implements the methods and specialize accordingly.

[vyzo]

can we avoid exporting those two?

[vyzo]

or at least rename them, these are ugly names.

[fare]

What names would you suggest? They are what std/text/json uses to recognize it's being given a walist.

[fare]

base-walist ? wrapped-alist ?

[vyzo]

lets call the base walist, thats what the users will be working with.
Also, the accessor should be export renamed to walist->list i think.

[fare]

If the base is walist, what is the pure equal one called? The same, and I override the rest? Then it's not final?

[fare]

Why walist->list rather than walist->alist ?

[fare]

What do you think of this refactoring? If you like it, I can squash the commits together.

[vyzo]

LGTM.
Feel free to squash merge.