[GHC] #14812: Dot-Notation for Flipped Function Application

[GHC]

#14812: Dot-Notation for Flipped Function Application
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        Reporter:  tepan             |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by svenpanne):

 Just to reiterate a few points:

 The fact that `Foo.bar` is a single entity is a ''lexical'' issue, as you
 can see in the Haskell report
 (https://www.haskell.org/onlinereport/haskell2010/haskellch10.html#x17-17700010.2,
 look for ''modid''). Of course whitespace is relevant on that level. The
 initial proposal
 (https://mail.haskell.org/pipermail/libraries/2001-February/000258.html)
 already mentions that this syntax effectively steals some syntax with
 previously different semantics, but the consensus was that this is not
 nice, but OK: Hierarchical names are a big win and chaining constructors
 with dots but without whitespace was considered sufficiently rare.

 Your proposal would steal yet another syntax and give it completely
 different semantics for a very low benefit: `foo.bar` is currently
 semantically equivalent to `foo . bar`, and you propose to change that to
 `bar $ foo`. I bet this will break lots of code, and one should have a
 very, very good reason to do that. Emulating some surface syntax from a
 different programming paradigm is not really enough for that.

 Furthermore, you would introduce syntactic ambiguity for `Foo.bar`,
 because one can't distinguish module names and constructor names on the
 lexical level. This needs to be resolved to the meaning "hierarchical
 name", but obscure, non-regular things like this are warts in any language
 design, so plesase let's not do this.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14812#comment:8>
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