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This module deals with printing C string literals
\begin{code}
module CStrings(
CLabelString, isCLabelString,
cSEP, pp_cSEP,
stringToC, charToC, pprFSInCStyle,
charToEasyHaskell
) where
#include "HsVersions.h"
import Char ( ord, chr, isAlphaNum )
import Outputable
\end{code}
\begin{code}
type CLabelString = FAST_STRING -- A C label, completely unencoded
isCLabelString :: CLabelString -> Bool -- Checks to see if this is a valid C label
isCLabelString lbl
= all ok (_UNPK_ lbl)
where
ok c = isAlphaNum c || c == '_' || c == '.'
-- The '.' appears in e.g. "foo.so" in the
-- module part of a ExtName. Maybe it should be separate
cSEP = SLIT("_") -- official C separator
pp_cSEP = char '_'
\end{code}
\begin{code}
pprFSInCStyle :: FAST_STRING -> SDoc
pprFSInCStyle fs = doubleQuotes (text (stringToC (_UNPK_ fs)))
stringToC :: String -> String
-- Convert a string to the form required by C in a C literal string
-- Tthe hassle is what to do w/ strings like "ESC 0"...
stringToC "" = ""
stringToC [c] = charToC c
stringToC (c:cs)
-- if we have something "octifiable" in "c", we'd better "octify"
-- the rest of the string, too.
= if (c < ' ' || c > '~')
then (charToC c) ++ (concat (map char_to_C cs))
else (charToC c) ++ (stringToC cs)
where
char_to_C c | c == '\n' = "\\n" -- use C escapes when we can
| c == '\a' = "\\a"
| c == '\b' = "\\b" -- ToDo: chk some of these...
| c == '\r' = "\\r"
| c == '\t' = "\\t"
| c == '\f' = "\\f"
| c == '\v' = "\\v"
| otherwise = '\\' : (octify (ord c))
charToC :: Char -> String
-- Convert a character to the form reqd in a C character literal
charToC c = if (c >= ' ' && c <= '~') -- non-portable...
then case c of
'\'' -> "\\'"
'\\' -> "\\\\"
'"' -> "\\\""
'\n' -> "\\n"
'\a' -> "\\a"
'\b' -> "\\b"
'\r' -> "\\r"
'\t' -> "\\t"
'\f' -> "\\f"
'\v' -> "\\v"
_ -> [c]
else '\\' : (octify (ord c))
charToEasyHaskell :: Char -> String
-- Convert a character to the form reqd in a Haskell character literal
charToEasyHaskell c
= if (c >= 'a' && c <= 'z')
|| (c >= 'A' && c <= 'Z')
|| (c >= '0' && c <= '9')
then [c]
else case c of
_ -> '\\' : show (ord c)
octify :: Int -> String
octify n
= if n < 8 then
[chr (n + ord '0')]
else
octify (n `quot` 8) ++ [chr (n `rem` 8 + ord '0')]
\end{code}
|
