#2652: fancier prompts for ghci
------------------------------+---------------------------------------------
Reporter: jsnx | Owner:
Type: feature request | Status: new
Priority: normal | Milestone: 6.10 branch
Component: GHCi | Version: 6.8.3
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: | Architecture: Unknown/Multiple
Os: Unknown/Multiple |
------------------------------+---------------------------------------------
Comment (by jsnx):
I've integrated this with GHC 6.8.3 sources. There's not much to it.
{{{
#!diff
--- 0/compiler/ghci/InteractiveUI.hs 2008-06-16 10:27:16.000000000
-0700
+++ 1/compiler/ghci/InteractiveUI.hs 2008-10-28 02:57:03.000000000
-0700
@@ -1447,11 +1447,19 @@
setPrompt value = do
st <- getGHCiState
if null value
- then io $ hPutStrLn stderr $ "syntax: :set prompt <prompt>,
currently \"" ++ prompt st ++ "\""
- else setGHCiState st{ prompt = remQuotes value }
+ then io $ hPutStrLn stderr $
+ "syntax: :set prompt <prompt>, currently \"" ++ prompt st ++ "\""
+ else setGHCiState st{ prompt = read . handleQuotes $ value }
where
- remQuotes ('\"':xs) | not (null xs) && last xs == '\"' = init xs
- remQuotes x = x
+ -- the prompt can be input with quote marks and string escaping, or
+ -- with plain character escaping.
+ handleQuotes s | length s > 2 && last s == '"' && head s == '"' = s
+ | otherwise = wrap . escapeQuotes $ s
+ wrap = ("\"" ++) . (++ "\"")
+ escapeQuotes ('\\':'"':r) = '\\' : '"' : escapeQuotes r
+ escapeQuotes ('"':r) = '\\' : '"' : escapeQuotes r
+ escapeQuotes (c:r) = c : escapeQuotes r
+ escapeQuotes [ ] = [ ]
setOptions wds =
do -- first, deal with the GHCi opts (+s, +t, etc.)
}}}
With quotes, it uses string escapes and retains spaces:
{{{
Prelude> :set prompt "{- %s\n -} "
{- Prelude
-}
}}}
Without quotes, it uses only character escapes:
{{{
Prelude> :set prompt {-\SP\SP%s\n\SP-}\SP
{- Prelude
-}
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2652#comment:3>
GHC <http://www.haskell.org/ghc/>
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