[wg-camlp4] PG'OCaml and syntax proliferation

[Alain Frisch]

On 01/28/2013 04:10 PM, Dario Teixeira wrote:
>    let fetch_users dbh =
>          PGSQL(dbh) "select id, name from users"
>
> This is syntactally incorrect, of course.

I've written Caml code for 17 years, and it was not clear to me that 
this is syntactically incorrect, I had to try...

As an alternative but close enough syntax, I suggest:

(PGSQL dbh) "select id, name from users"

or:

(PGSQL) dbg "select id, name from users"

Since a constructor never evaluates to a function, it remains clear 
enough that these two forms are special.

> I could go on.  Anyway, regardless of choice, one issue comes to mind.
> Presently, code using the PG'OCaml syntax extension is conspicuous by its
> syntactic incorrectness.    Therefore, someone unfamiliar with
 > PG'OCaml who happened to be looking at code using the syntax
 > extension would immediately suspect something camlp4ish was going on.

Good point.

What do you think of the proposals above?  They are "trivially" wrong 
OCaml code, although not on a strictly syntactic criterion (but a simple 
local typing criterion is close enough).

>    let fetch_users dbh =
>          `PGSQL' (dbh, "select id, name from users")

This is also an option.  I agree that it's a good idea to reach some 
consensus about such guidelines (and I know it will be difficult, as for 
any syntactic choice!).



Alain