2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[HsLit]{Abstract syntax: source-language literals}
9 #include "HsVersions.h"
11 import {-# SOURCE #-} HsExpr( SyntaxExpr )
15 import Ratio ( Rational )
19 %************************************************************************
21 \subsection[HsLit]{Literals}
23 %************************************************************************
28 = HsChar Char -- Character
29 | HsCharPrim Char -- Unboxed character
30 | HsString FastString -- String
31 | HsStringPrim FastString -- Packed string
32 | HsInt Integer -- Genuinely an Int; arises from TcGenDeriv,
33 -- and from TRANSLATION
34 | HsIntPrim Integer -- Unboxed Int
35 | HsInteger Integer Type -- Genuinely an integer; arises only from TRANSLATION
36 -- (overloaded literals are done with HsOverLit)
37 | HsRat Rational Type -- Genuinely a rational; arises only from TRANSLATION
38 -- (overloaded literals are done with HsOverLit)
39 | HsFloatPrim Rational -- Unboxed Float
40 | HsDoublePrim Rational -- Unboxed Double
42 instance Eq HsLit where
43 (HsChar x1) == (HsChar x2) = x1==x2
44 (HsCharPrim x1) == (HsCharPrim x2) = x1==x2
45 (HsString x1) == (HsString x2) = x1==x2
46 (HsStringPrim x1) == (HsStringPrim x2) = x1==x2
47 (HsInt x1) == (HsInt x2) = x1==x2
48 (HsIntPrim x1) == (HsIntPrim x2) = x1==x2
49 (HsInteger x1 _) == (HsInteger x2 _) = x1==x2
50 (HsRat x1 _) == (HsRat x2 _) = x1==x2
51 (HsFloatPrim x1) == (HsFloatPrim x2) = x1==x2
52 (HsDoublePrim x1) == (HsDoublePrim x2) = x1==x2
55 data HsOverLit id -- An overloaded literal
56 = HsIntegral Integer (SyntaxExpr id) -- Integer-looking literals;
57 | HsFractional Rational (SyntaxExpr id) -- Frac-looking literals
58 -- Before type checking, the SyntaxExpr is 'fromInteger' or 'fromRational'
59 -- After type checking, it is (fromInteger 3) or lit_78; that is,
60 -- the expression that should replace the literal.
61 -- This is unusual, because we're replacing 'fromInteger' with a call
62 -- to fromInteger. Reason: it allows commoning up of the fromInteger
63 -- calls, which wouldn't be possible if the desguarar made the application
65 -- Comparison operations are needed when grouping literals
66 -- for compiling pattern-matching (module MatchLit)
67 instance Eq (HsOverLit id) where
68 (HsIntegral i1 _) == (HsIntegral i2 _) = i1 == i2
69 (HsFractional f1 _) == (HsFractional f2 _) = f1 == f2
72 instance Ord (HsOverLit id) where
73 compare (HsIntegral i1 _) (HsIntegral i2 _) = i1 `compare` i2
74 compare (HsIntegral _ _) (HsFractional _ _) = LT
75 compare (HsFractional f1 _) (HsFractional f2 _) = f1 `compare` f2
76 compare (HsFractional f1 _) (HsIntegral _ _) = GT
80 instance Outputable HsLit where
81 -- Use "show" because it puts in appropriate escapes
82 ppr (HsChar c) = pprHsChar c
83 ppr (HsCharPrim c) = pprHsChar c <> char '#'
84 ppr (HsString s) = pprHsString s
85 ppr (HsStringPrim s) = pprHsString s <> char '#'
86 ppr (HsInt i) = integer i
87 ppr (HsInteger i _) = integer i
88 ppr (HsRat f _) = rational f
89 ppr (HsFloatPrim f) = rational f <> char '#'
90 ppr (HsDoublePrim d) = rational d <> text "##"
91 ppr (HsIntPrim i) = integer i <> char '#'
93 instance Outputable (HsOverLit id) where
94 ppr (HsIntegral i _) = integer i
95 ppr (HsFractional f _) = rational f