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%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[PrefixSyn]{``Prefix-form'' syntax}
This module contains an algebraic data type into which a prefix form
string from the current Haskell parser is converted. Given in an
order that follows the \tr{Prefix_Form} document.
\begin{code}
module PrefixSyn (
RdrBinding(..),
RdrMatch(..),
SigConverter,
SrcFile,
SrcFun,
SrcLine,
readInteger
) where
#include "HsVersions.h"
import HsSyn
import RdrHsSyn
import RdrName ( RdrName )
import Panic ( panic )
import Char ( isDigit, ord )
--UNUSED: type RdrId = RdrName
type SrcLine = Int
type SrcFile = FAST_STRING
type SrcFun = RdrName
\end{code}
\begin{code}
data RdrBinding
= -- On input we use the Empty/And form rather than a list
RdrNullBind
| RdrAndBindings RdrBinding RdrBinding
-- Value bindings havn't been united with their
-- signatures yet
| RdrValBinding RdrNameMonoBinds
-- Signatures are mysterious; we can't
-- tell if its a Sig or a ClassOpSig,
-- so we just save the pieces:
| RdrSig RdrNameSig
-- The remainder all fit into the main HsDecl form
| RdrHsDecl RdrNameHsDecl
type SigConverter = RdrNameSig -> RdrNameSig
\end{code}
\begin{code}
data RdrMatch
= RdrMatch
[RdrNamePat]
(Maybe RdrNameHsType)
RdrNameGRHSs
\end{code}
Unscramble strings representing oct/dec/hex integer literals:
\begin{code}
readInteger :: String -> Integer
readInteger ('-' : xs) = - (readInteger xs)
readInteger ('0' : 'o' : xs) = chk (stoo 0 xs)
readInteger ('0' : 'x' : xs) = chk (stox 0 xs)
readInteger ['0'] = 0 -- efficiency shortcut?
readInteger ['1'] = 1 -- ditto?
readInteger xs = chk (stoi 0 xs)
chk (i, "") = i
chk (i, junk) = panic ("readInteger: junk after reading:"++junk)
stoo, stoi, stox :: Integer -> String -> (Integer, String)
stoo a (c:cs) | is_oct c = stoo (a*8 + ord_ c - ord_0) cs
stoo a cs = (a, cs)
stoi a (c:cs) | isDigit c = stoi (a*10 + ord_ c - ord_0) cs
stoi a cs = (a, cs)
stox a (c:cs) | isDigit c = stox (a_16_ord_c - ord_0) cs
| is_hex c = stox (a_16_ord_c - ord_a + 10) cs
| is_Hex c = stox (a_16_ord_c - ord_A + 10) cs
where a_16_ord_c = a*16 + ord_ c
stox a cs = (a, cs)
is_oct c = c >= '0' && c <= '7'
is_hex c = c >= 'a' && c <= 'f'
is_Hex c = c >= 'A' && c <= 'F'
ord_ c = toInteger (ord c)
ord_0, ord_a, ord_A :: Integer
ord_0 = ord_ '0'; ord_a = ord_ 'a'; ord_A = ord_ 'A'
\end{code}
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