From: oleg@okmij.org
To: jun.furuse@gmail.com, caml-list@inria.fr
Subject: Re: [Caml-list] [ANN] ppx_monadic.1.0.2, ppx for monadic do,
Date: Mon, 19 Jan 2015 02:33:03 -0500 (EST) [thread overview]
Message-ID: <20150119073303.038ECC38BA@www1.g3.pair.com> (raw)
In-Reply-To: <CAAoLEWvdRt=nVRKD7d2fVvxeLujurV4+jMaEkm6VWg+oQHrdoQ@mail.gmail.com>
> Current OCaml syntax has shortage of pattern binding expression and
> only usable is let%xxx p = e in which is a bit pain for ppx writers.
Indeed. One may wish that
let rec p = e1 in e2
were treated as if it were
let[@ocaml.let "rec"] p = e1 in e2
and likewise let module. Come to think of it, 'rec! or 'module' are
annotations on let. Then we can generalize so that
let something p = e1 in e2
(where something is any reserved word or an operator -- something that
cannot be mistaken for a regular identifier) is parsed as if it were
let[@ocaml.let "something"] p = e1 in e2
The type-checker will complain if it finds the ocaml.let attribute it
does not understand. (Therefore, Typedtree does not have to be changed
-- although one may wish for a specifically letrec node). Thus we
can define let !, let >>=, let LWP, let struct, let when, let if and all other
potentially useful binding forms.
next prev parent reply other threads:[~2015-01-19 7:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-13 14:23 [Caml-list] [ANN] ppx_monadic.1.0.2, ppx for monadic do, pattern guards and monadic comprehension Jun Furuse
2015-01-14 8:40 ` [Caml-list] [ANN] ppx_monadic.1.0.2, ppx for monadic do, pattern oleg
2015-01-18 14:47 ` Jun Furuse
2015-01-19 7:33 ` oleg [this message]
2015-01-19 8:34 ` [Caml-list] [ANN] ppx_monadic.1.0.2, ppx for monadic do, Alain Frisch
2015-01-19 9:06 ` Gabriel Scherer
2015-01-19 9:40 ` Alain Frisch
2015-01-19 16:10 ` Jeremy Yallop
2015-01-19 8:56 ` [Caml-list] [ANN] ppx_monadic.1.0.2, ppx for monadic do, pattern Alain Frisch
2015-01-19 21:52 ` Drup
2015-01-20 3:53 ` Jun Furuse
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