#4430: Better support for resolving infix expressions in template haskell
---------------------------------+------------------------------------------
Reporter: reinerp | Owner: igloo
Type: feature request | Status: patch
Priority: normal | Milestone: 7.4.1
Component: Template Haskell | Version: 6.12.3
Keywords: | Testcase:
Blockedby: | Difficulty:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: None/Unknown
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Comment(by reinerp):
I'm confused. My patch implements the following:
{{{
InfixE Nothing + (UInfixE a + b) ---> SectionR + (OpApp a + b)
InfixE Nothing + (ParensE $ UInfixE a + b) ---> SectionR + (HsPar $ OpApp
a + b)
}}}
This means that we can use the first to represent {{{(+ a + b)}}} and the
second to represent {{{(+ (a + b))}}}. All good, we can represent the
things we need to. The problem is that {{{InfixE}}} behaves quite
differently for sections than it does for non-sections (the special
handling I discussed in commment 15).
It seems there are two ways to proceed:
1. Leave the situation with sections as implemented in my patch, so
{{{UInfixE}}} doesn't need to worry about sections, at the cost of some
special cases in {{{InfixE}}}
2. Remove the special cases of {{{InfixE}}} by making the {{{UInfixE}}}
constructor handle sections:
{{{
data Exp =
...
UInfixE (Maybe Exp) Exp (Maybe Exp)
...
}}}
Which are you suggesting?
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4430#comment:21>
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