X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FhsSyn%2FHsLit.lhs;h=def1e352db337d5fec2321d870310577ef886c04;hp=0874dda85815c116abd60da8f908ffbc8bb92078;hb=3391a03562d4056de7b16cd0f632e6c43ae44cca;hpb=f278f0676579f67075033a4f9857715909c4b71e diff --git a/compiler/hsSyn/HsLit.lhs b/compiler/hsSyn/HsLit.lhs index 0874dda..def1e35 100644 --- a/compiler/hsSyn/HsLit.lhs +++ b/compiler/hsSyn/HsLit.lhs @@ -12,7 +12,8 @@ module HsLit where #include "HsVersions.h" import {-# SOURCE #-} HsExpr( SyntaxExpr, pprExpr ) -import HsTypes (PostTcType) +import BasicTypes ( FractionalLit(..) ) +import HsTypes ( PostTcType ) import Type ( Type ) import Outputable import FastString @@ -63,15 +64,14 @@ instance Eq HsLit where data HsOverLit id -- An overloaded literal = OverLit { ol_val :: OverLitVal, - ol_rebindable :: Bool, -- True <=> rebindable syntax - -- False <=> standard syntax + ol_rebindable :: Bool, -- Note [ol_rebindable] ol_witness :: SyntaxExpr id, -- Note [Overloaded literal witnesses] ol_type :: PostTcType } deriving (Data, Typeable) data OverLitVal = HsIntegral !Integer -- Integer-looking literals; - | HsFractional !Rational -- Frac-looking literals + | HsFractional !FractionalLit -- Frac-looking literals | HsIsString !FastString -- String-looking literals deriving (Data, Typeable) @@ -79,6 +79,19 @@ overLitType :: HsOverLit a -> Type overLitType = ol_type \end{code} +Note [ol_rebindable] +~~~~~~~~~~~~~~~~~~~~ +The ol_rebindable field is True if this literal is actually +using rebindable syntax. Specifically: + + False iff ol_witness is the standard one + True iff ol_witness is non-standard + +Equivalently it's True if + a) RebindableSyntax is on + b) the witness for fromInteger/fromRational/fromString + that happens to be in scope isn't the standard one + Note [Overloaded literal witnesses] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ *Before* type checking, the SyntaxExpr in an HsOverLit is the @@ -89,7 +102,7 @@ This witness should replace the literal. This dual role is unusual, because we're replacing 'fromInteger' with a call to fromInteger. Reason: it allows commoning up of the fromInteger -calls, which wouldn't be possible if the desguarar made the application +calls, which wouldn't be possible if the desguarar made the application. The PostTcType in each branch records the type the overload literal is found to have. @@ -143,6 +156,6 @@ instance OutputableBndr id => Outputable (HsOverLit id) where instance Outputable OverLitVal where ppr (HsIntegral i) = integer i - ppr (HsFractional f) = rational f + ppr (HsFractional f) = text (fl_text f) ppr (HsIsString s) = pprHsString s \end{code}