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Add support for more characters to UnicodeSyntax

Here is a short patch to add support for some more Unicode characters when GHC is used with the -XUnicodeSyntax extension.

  1. The following are enabled when used with Arrows:
  • (LEFTWARDS ARROW-TAIL) = -<
  • (RIGHTWARDS ARROW-TAIL) = >-
  • (LEFTWARDS DOUBLE ARROW-TAIL) = -<<
  • (RIGHTWARDS DOUBLE ARROW-TAIL) = >>-
  1. The star '' is allowed instead of '*' in kind signatures.

I would also like to propose a couple of changes that I have been unable to figure out how to implement myself (I tried adding them to Lexer.x but this had no effect). They all follow a similar theme:

  • For TemplateHaskell: ⟦ ⟧ (MATHEMATICAL _ WHITE SQUARE BRACKET) can be used instead of [| |]
  • For Generics: ⦃ ⦄ (_ WHITE CURLY BRACKET) can be used instead of {| |}
  • For Arrows: ⦇ ⦈ (Z NOTATION _ IMAGE BRACKET) can be used instead of (| |)
Trac metadata
Trac field Value
Version 6.10.1
Type FeatureRequest
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler
Test case
Differential revisions
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Blocking
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