#include "HsVersions.h"
-import Char ( isDigit, isAlpha, isUpper, isLower, ISALPHANUM, ord, chr, digitToInt, intToDigit )
+import Char ( isDigit, isAlpha, isUpper, isLower, ISALPHANUM, ord, chr, digitToInt )
import Util ( thenCmp )
import FiniteMap ( FiniteMap, emptyFM, lookupFM, addToFM, elemFM )
import Outputable
* Most other printable characters translate to 'zx' or 'Zx' for some
alphabetic character x
-* The others translate as 'zxdd' where 'dd' is exactly two hexadecimal
- digits for the ord of the character
+* The others translate as 'znnnU' where 'nnn' is the decimal number
+ of the character
Before After
--------------------------
encode_ch '*' = "zt"
encode_ch '_' = "zu"
encode_ch '%' = "zv"
-encode_ch c = ['z', 'x', intToDigit hi, intToDigit lo]
- where
- (hi,lo) = ord c `quotRem` 16
+encode_ch c = 'z' : shows (ord c) "U"
\end{code}
Decode is used for user printing.
decode_escape ('t' : rest) = '*' : decode rest
decode_escape ('u' : rest) = '_' : decode rest
decode_escape ('v' : rest) = '%' : decode rest
-decode_escape ('x' : d1 : d2 : rest) = chr (digitToInt d1 * 16 + digitToInt d2) : decode rest
-- Tuples are coded as Z23T
+-- Characters not having a specific code are coded as z224U
decode_escape (c : rest)
| isDigit c = go (digitToInt c) rest
where
go n (c : rest) | isDigit c = go (10*n + digitToInt c) rest
go n ('T' : rest) = '(' : replicate n ',' ++ ')' : decode rest
+ go n ('U' : rest) = chr n : decode rest
go n other = pprPanic "decode_escape" (ppr n <+> text (c:rest))
decode_escape (c : rest) = pprTrace "decode_escape" (char c) (decode rest)