You can now give :main a Haskell [String] as an argument, e.g.
:main ["foo", "bar"]
and :run is a variant that takes the name of the function to run.
Also, :main now obeys the -main-is flag.
("print", keepGoing printCmd, Nothing, completeIdentifier),
("quit", quit, Nothing, completeNone),
("reload", keepGoing reloadModule, Nothing, completeNone),
+ ("run", keepGoing runRun, Nothing, completeIdentifier),
("set", keepGoing setCmd, Just flagWordBreakChars, completeSetOptions),
("show", keepGoing showCmd, Nothing, completeNone),
("sprint", keepGoing sprintCmd, Nothing, completeIdentifier),
keepGoing a str = a str >> return False
keepGoingPaths :: ([FilePath] -> GHCi ()) -> (String -> GHCi Bool)
-keepGoingPaths a str = a (toArgs str) >> return False
+keepGoingPaths a str
+ = do case toArgs str of
+ Left err -> io (hPutStrLn stderr err)
+ Right args -> a args
+ return False
shortHelpText :: String
shortHelpText = "use :? for help.\n"
" :module [+/-] [*]<mod> ... set the context for expression evaluation\n" ++
" :quit exit GHCi\n" ++
" :reload reload the current module set\n" ++
+ " :run function [<arguments> ...] run the function with the given arguments\n" ++
" :type <expr> show the type of <expr>\n" ++
" :undef <cmd> undefine user-defined command :<cmd>\n" ++
" :!<command> run the shell command <command>\n" ++
| otherwise = ppr fix <+> ppr (GHC.getName thing)
runMain :: String -> GHCi ()
-runMain args = do
- let ss = concat $ intersperse "," (map (\ s -> ('"':s)++"\"") (toArgs args))
- enqueueCommands ['[': ss ++ "] `System.Environment.withArgs` main"]
+runMain s = case toArgs s of
+ Left err -> io (hPutStrLn stderr err)
+ Right args ->
+ do dflags <- getDynFlags
+ case mainFunIs dflags of
+ Nothing -> doWithArgs args "main"
+ Just f -> doWithArgs args f
+
+runRun :: String -> GHCi ()
+runRun s = case toCmdArgs s of
+ Left err -> io (hPutStrLn stderr err)
+ Right (cmd, args) -> doWithArgs args cmd
+
+doWithArgs :: [String] -> String -> GHCi ()
+doWithArgs args cmd = enqueueCommands ["System.Environment.withArgs " ++
+ show args ++ " (" ++ cmd ++ ")"]
addModule :: [FilePath] -> GHCi ()
addModule files = do
,Opt_PrintEvldWithShow
]
setCmd str
- = case toArgs str of
- ("args":args) -> setArgs args
- ("prog":prog) -> setProg prog
- ("prompt":_) -> setPrompt (after 6)
- ("editor":_) -> setEditor (after 6)
- ("stop":_) -> setStop (after 4)
- wds -> setOptions wds
- where after n = dropWhile isSpace $ drop n $ dropWhile isSpace str
-
-setArgs, setProg, setOptions :: [String] -> GHCi ()
-setEditor, setStop, setPrompt :: String -> GHCi ()
+ = case getCmd str of
+ Right ("args", rest) ->
+ case toArgs rest of
+ Left err -> io (hPutStrLn stderr err)
+ Right args -> setArgs args
+ Right ("prog", rest) ->
+ case toArgs rest of
+ Right [prog] -> setProg prog
+ _ -> io (hPutStrLn stderr "syntax: :set prog <progname>")
+ Right ("prompt", rest) -> setPrompt $ dropWhile isSpace rest
+ Right ("editor", rest) -> setEditor $ dropWhile isSpace rest
+ Right ("stop", rest) -> setStop $ dropWhile isSpace rest
+ _ -> case toArgs str of
+ Left err -> io (hPutStrLn stderr err)
+ Right wds -> setOptions wds
+
+setArgs, setOptions :: [String] -> GHCi ()
+setProg, setEditor, setStop, setPrompt :: String -> GHCi ()
setArgs args = do
st <- getGHCiState
setGHCiState st{ args = args }
-setProg [prog] = do
+setProg prog = do
st <- getGHCiState
setGHCiState st{ progname = prog }
-setProg _ = do
- io (hPutStrLn stderr "syntax: :set prog <progname>")
setEditor cmd = do
st <- getGHCiState
-- module names
looksLikeModuleName,
- toArgs,
+ getCmd, toCmdArgs, toArgs,
-- Floating point stuff
readRational,
\end{code}
Akin to @Prelude.words@, but acts like the Bourne shell, treating
-quoted strings and escaped characters within the input as solid blocks
-of characters. Doesn't raise any exceptions on malformed escapes or
-quoting.
+quoted strings as Haskell Strings, and also parses Haskell [String]
+syntax.
\begin{code}
-toArgs :: String -> [String]
-toArgs "" = []
-toArgs s =
- case dropWhile isSpace s of -- drop initial spacing
- [] -> [] -- empty, so no more tokens
- rem -> let (tok,aft) = token rem [] in tok : toArgs aft
+getCmd :: String -> Either String -- Error
+ (String, String) -- (Cmd, Rest)
+getCmd s = case break isSpace $ dropWhile isSpace s of
+ ([], _) -> Left ("Couldn't find command in " ++ show s)
+ res -> Right res
+
+toCmdArgs :: String -> Either String -- Error
+ (String, [String]) -- (Cmd, Args)
+toCmdArgs s = case getCmd s of
+ Left err -> Left err
+ Right (cmd, s') -> case toArgs s' of
+ Left err -> Left err
+ Right args -> Right (cmd, args)
+
+toArgs :: String -> Either String -- Error
+ [String] -- Args
+toArgs str
+ = case dropWhile isSpace str of
+ s@('[':_) -> case reads s of
+ [(args, spaces)]
+ | all isSpace spaces ->
+ Right args
+ _ ->
+ Left ("Couldn't read " ++ show str ++ "as [String]")
+ s -> toArgs' s
where
- -- Grab a token off the string, given that the first character exists and
- -- isn't whitespace. The second argument is an accumulator which has to be
- -- reversed at the end.
- token [] acc = (reverse acc,[]) -- out of characters
- token ('\\':c:aft) acc -- escapes
- = token aft ((escape c) : acc)
- token (q:aft) acc | q == '"' || q == '\'' -- open quotes
- = let (aft',acc') = quote q aft acc in token aft' acc'
- token (c:aft) acc | isSpace c -- unescaped, unquoted spacing
- = (reverse acc,aft)
- token (c:aft) acc -- anything else goes in the token
- = token aft (c:acc)
-
- -- Get the appropriate character for a single-character escape.
- escape 'n' = '\n'
- escape 't' = '\t'
- escape 'r' = '\r'
- escape c = c
-
- -- Read into accumulator until a quote character is found.
- quote qc =
- let quote' [] acc = ([],acc)
- quote' ('\\':c:aft) acc = quote' aft ((escape c) : acc)
- quote' (c:aft) acc | c == qc = (aft,acc)
- quote' (c:aft) acc = quote' aft (c:acc)
- in quote'
+ toArgs' s = case dropWhile isSpace s of
+ [] -> Right []
+ ('"' : _) -> case reads s of
+ [(arg, rest)]
+ -- rest must either be [] or start with a space
+ | all isSpace (take 1 rest) ->
+ case toArgs' rest of
+ Left err -> Left err
+ Right args -> Right (arg : args)
+ _ ->
+ Left ("Couldn't read " ++ show s ++ "as String")
+ s' -> case break isSpace s' of
+ (arg, s'') -> case toArgs' s'' of
+ Left err -> Left err
+ Right args -> Right (arg : args)
\end{code}
-- -----------------------------------------------------------------------------
</sect3>
<sect3>
- <title>The <literal>:main</literal> command</title>
+ <title>The <literal>:main</literal> and <literal>:run</literal> commands</title>
<para>
When a program is compiled and executed, it can use the
["foo","bar"]
</screen>
+ <para>
+ We can also quote arguments which contains characters like
+ spaces, and they are treated like Haskell strings, or we can
+ just use Haskell list syntax:
+ </para>
+
+<screen>
+Prelude> :main foo "bar baz"
+["foo","bar baz"]
+Prelude> :main ["foo", "bar baz"]
+["foo","bar baz"]
+</screen>
+
+ <para>
+ Finally, other functions can be called, either with the
+ <literal>-main-is</literal> flag or the <literal>:run</literal>
+ command:
+ </para>
+
+<screen>
+Prelude> let foo = putStrLn "foo" >> System.Environment.getArgs >>= print
+Prelude> let bar = putStrLn "bar" >> System.Environment.getArgs >>= print
+Prelude> :set -main-is foo
+Prelude> :main foo "bar baz"
+foo
+["foo","bar baz"]
+Prelude> :run bar ["foo", "bar baz"]
+bar
+["foo","bar baz"]
+</screen>
+
</sect3>
</sect2>
["foo","bar"]
</screen>
+ <para>
+ We can also quote arguments which contains characters like
+ spaces, and they are treated like Haskell strings, or we can
+ just use Haskell list syntax:
+ </para>
+
+<screen>
+Prelude> :main foo "bar baz"
+["foo","bar baz"]
+Prelude> :main ["foo", "bar baz"]
+["foo","bar baz"]
+</screen>
+
+ <para>
+ Finally, other functions can be called, either with the
+ <literal>-main-is</literal> flag or the <literal>:run</literal>
+ command:
+ </para>
+
+<screen>
+Prelude> let foo = putStrLn "foo" >> System.Environment.getArgs >>= print
+Prelude> let bar = putStrLn "bar" >> System.Environment.getArgs >>= print
+Prelude> :set -main-is foo
+Prelude> :main foo "bar baz"
+foo
+["foo","bar baz"]
+Prelude> :run bar ["foo", "bar baz"]
+bar
+["foo","bar baz"]
+</screen>
+
</listitem>
</varlistentry>
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