New syntax extension about eliom HOT 5 CLOSED

What I'm thinking for now :

• For top level declarations [%%client ... ] [%%server ... ] and [%%shared ... ] instead of {client{ ... }} {server{ ... } and {shared{ ... }}.
  As added bonus, let%server = .... will work at the toplevel. Also, since the syntax is going to be slightly different than the one for expressions, it may help solve an ambiguity for beginners.
• For client values, I propose ( ... )[@cval ty] instead of {ty{ ... }}. (or simply ( ... )[@cval]).
  Other form will also implicitly work, for exemple begin[@cval ty] ... end, which is nice.
• For injections [%inj ...] instead of %x and %(...). It's a bit more verbose, unfortunatly. I asked @alainfrisch if it was possible to use ( ... )%inj, but it's not possible.
  We could use this occasion to differenciate between injections inside a cval and injections inside a client section. It would help solve #17.

@balat, @benozol, Did I forget anything ? @alainfrisch, do you have better suggestions ?

from eliom.

I don't have any experience with writing client/server mechanism in Ocsigen, so I cannot really comment.

In order to mark "sections" of code, you could also use extension nodes or attributes as delimiters. Instead of [%%client ...], you could do:

[%%client]
....
[%%both]

This could be more robust w.r.t. other syntactic tools, since it would make the content of the section appear in the normal stream of structure items, not nested under the extension node.

For injection: if this is syntactically a unary prefix operator, did you consider using an actual operator symbol (e.g. "!!" or "~~")?

from eliom.

I prefer to have explicit delimiters for sections. And I really like let%server, so we will need to have [%server ... ] anyway. I don't think it's going to be that much of an issue with other syntax extensions, since the code modification done by eliom is minimal. Maybe we can have both with another syntax, like [%%server_section] buh meh.

Indeed, we could use an operator, but the potential of breaking something else is extremely high, so I'm not very fond of it.

from eliom.

The operator could be (re)defined by the user, as is:

[%%ocsigen.injection "~~"]

This would give a way to resolve clashes locally.

from eliom.

That's an interesting solution. We could use ~% by default to have minimal modification with the current state, which is nice.

from eliom.