Use FractionalLit more extensively to improve other pretty printers

[ghc-hetmet.git] / compiler / hsSyn / HsLit.lhs

diff --git a/compiler/hsSyn/HsLit.lhs b/compiler/hsSyn/HsLit.lhs
index 0874dda..2cda103 100644 (file)
--- 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
@@ -40,10 +41,10 @@ data HsLit
   | HsWordPrim     Integer             -- Unboxed Word
   | HsInteger      Integer  Type       -- Genuinely an integer; arises only from TRANSLATION
                                        --      (overloaded literals are done with HsOverLit)
-  | HsRat          Rational Type       -- Genuinely a rational; arises only from TRANSLATION
+  | HsRat          FractionalLit Type  -- Genuinely a rational; arises only from TRANSLATION
                                        --      (overloaded literals are done with HsOverLit)
-  | HsFloatPrim            Rational            -- Unboxed Float
-  | HsDoublePrim    Rational           -- Unboxed Double
+  | HsFloatPrim            FractionalLit       -- Unboxed Float
+  | HsDoublePrim    FractionalLit      -- Unboxed Double
   deriving (Data, Typeable)
 
 instance Eq HsLit where
@@ -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.
@@ -130,9 +143,9 @@ instance Outputable HsLit where
     ppr (HsStringPrim s) = pprHsString s <> char '#'
     ppr (HsInt i)       = integer i
     ppr (HsInteger i _)         = integer i
-    ppr (HsRat f _)     = rational f
-    ppr (HsFloatPrim f)         = rational f <> char '#'
-    ppr (HsDoublePrim d) = rational d <> text "##"
+    ppr (HsRat f _)     = ppr f
+    ppr (HsFloatPrim f)         = ppr f <> char '#'
+    ppr (HsDoublePrim d) = ppr d <> text "##"
     ppr (HsIntPrim i)   = integer i  <> char '#'
     ppr (HsWordPrim w)  = integer w  <> text "##"
 
@@ -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) = ppr f
   ppr (HsIsString s)   = pprHsString s
 \end{code}