-ddump-types vs -fprint-explicit-foralls, and symbol-ness of worker/wrapper names [Re: [commit: ghc] master: Pretty-print the following TyThings via their IfaceDecl counterpart: * AnId * ACoAxiom * AConLike (065c35a) (fwd)]

[Dr. ÉRDI Gergő]

Exactly, the problem is precisely that $foo is regarded as an infix
operator in that code path, so with my change, it would be classified as
prefix.
On Mar 17, 2014 10:10 PM, "Simon Peyton Jones" <simonpj at microsoft.com>
wrote:

>   Do they show up in -ddump-simpl? It would be nice to keep that output
> as readable as possible, as there are quite a few of us that read it on a
> regular basis.
>
>
>
> I don't think so (because -ddump-simpl doesn't print **any** operators in
> parens) but I could be wrong, and I agree that would be bad.
>
>
>
> Does that mean that any operator that starts with $ will now not be
> considered infix for printing purposes?
>
>
>
> No, I believe that Gergo's suggestion is that a function be considered
> infix operator (for display purposes) only if all its characters are
> operator chars, rather than just the first one.
>
>
>
> Simon
>
>
>
> *From:* Johan Tibell [mailto:johan.tibell at gmail.com]
> *Sent:* 17 March 2014 14:00
> *To:* Simon Peyton Jones
> *Cc:* Dr. ERDI Gergo; GHC Devs
> *Subject:* Re: -ddump-types vs -fprint-explicit-foralls, and symbol-ness
> of worker/wrapper names [Re: [commit: ghc] master: Pretty-print the
> following TyThings via their IfaceDecl counterpart: * AnId * ACoAxiom *
> AConLike (065c35a) (fwd)]
>
>
>
> On Mon, Mar 17, 2014 at 2:45 PM, Simon Peyton Jones <simonpj at microsoft.com>
> wrote:
>
>  | The one interesting case is T4306 which fails because the generated
> name
>
> | $wupd is regarded as an infix name, and thus with my new code is
> | rendered as
> |
> |    ($wupd) :: GHC.Prim.Double# -> GHC.Prim.Double#
> |
> | instead of the old
> |
> |    $wupd :: GHC.Prim.Double# -> GHC.Prim.Double#
>
> I think it'd also be ok just to accept this output too. These "$wxx" names
> are generated by GHC and won't show up in user output.  It doesn't much
> matter displaying them in parens.
>
>
>
> Do they show up in -ddump-simpl? It would be nice to keep that output as
> readable as possible, as there are quite a few of us that read it on a
> regular basis.
>
>
>
>  But changing isLexVarSym is probably equally fine too.  I think (worth a
> check) that it's only called for display purposes, and not in any
> performance-critical parts.
>
> Whichever you choose, add a Note with isLexVarSym to explain the issue and
> the choice.
>
>
>
> Does that mean that any operator that starts with $ will now not be
> considered infix for printing purposes?
>
>
>
> -- Johan
>
>
>
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