[wg-camlp4] Request for feedback

Alain Frisch alain.frisch at lexifi.com
Thu Mar 14 11:34:04 GMT 2013

On 03/14/2013 12:00 PM, Leo White wrote:
> To be honest I am (cautiously) ok with "let%lwt x = ...".

If we only support the special form for "let", I agree it would make 
sense to make "let%ext" a single token.

I don't have a strong opinion about it, but if we special-case the 
treatment of the "let" binding, maybe it is worth introducing a custom 
kind of extension point for this construction, like supporting an 
arbitrary sequence of symbol characters:

   [%%lwt let suffix = "**"]
   [%%lazy let suffix = "..."]

      let** x1 = e1 in
      let** x2 = e2 in
      let... rec x = button "X" ~click:(fun () -> y # set_text "X")
      and  y = button "Y" ~click:(fun () -> x # set_text "Y")
      hbox [x; y]

> Note that for "let" the trade-off is potentially much worse:

It makes sense.

What do other people on the list think?

  - Should we support a compact syntax for extension nodes on all 
constructions starting with a keyword or delimiter (and if so, should 
this become the only syntax for extension nodes)?

  - If not, should be do it for the (local) let-binding only?  Or, if we 
special-case this construction, should we do something different for it 
altogether (arbitrary symbol characters)?


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