-
--- ------------------------------------------------------------------------
--- Passing commands to the OS on Windows
-
-{-
-On Windows this is tricky. We use CreateProcess, passing a single
-command-line string (lpCommandLine) as its argument. (CreateProcess
-is well documented on http://msdn.microsoft/com.)
-
- - It parses the beginning of the string to find the command. If the
- file name has embedded spaces, it must be quoted, using double
- quotes thus
- "foo\this that\cmd" arg1 arg2
-
- - The invoked command can in turn access the entire lpCommandLine string,
- and the C runtime does indeed do so, parsing it to generate the
- traditional argument vector argv[0], argv[1], etc. It does this
- using a complex and arcane set of rules which are described here:
-
- http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vccelng/htm/progs_12.asp
-
- (if this URL stops working, you might be able to find it by
- searching for "Parsing C Command-Line Arguments" on MSDN. Also,
- the code in the Microsoft C runtime that does this translation
- is shipped with VC++).
-
-Our goal in runProcess is to take a command filename and list of
-arguments, and construct a string which inverts the translatsions
-described above, such that the program at the other end sees exactly
-the same arguments in its argv[] that we passed to rawSystem.
-
-This inverse translation is implemented by 'translate' below.
-
-Here are some pages that give informations on Windows-related
-limitations and deviations from Unix conventions:
-
- http://support.microsoft.com/default.aspx?scid=kb;en-us;830473
- Command lines and environment variables effectively limited to 8191
- characters on Win XP, 2047 on NT/2000 (probably even less on Win 9x):
-
- http://www.microsoft.com/windowsxp/home/using/productdoc/en/default.asp?url=/WINDOWSXP/home/using/productdoc/en/percent.asp
- Command-line substitution under Windows XP. IIRC these facilities (or at
- least a large subset of them) are available on Win NT and 2000. Some
- might be available on Win 9x.
-
- http://www.microsoft.com/windowsxp/home/using/productdoc/en/default.asp?url=/WINDOWSXP/home/using/productdoc/en/Cmd.asp
- How CMD.EXE processes command lines.
-
-
-Note: CreateProcess does have a separate argument (lpApplicationName)
-with which you can specify the command, but we have to slap the
-command into lpCommandLine anyway, so that argv[0] is what a C program
-expects (namely the application name). So it seems simpler to just
-use lpCommandLine alone, which CreateProcess supports.
--}
-
-#if defined(mingw32_TARGET_OS)
-
--- Translate command-line arguments for passing to CreateProcess().
-translate :: String -> String
-translate str = '"' : snd (foldr escape (True,"\"") str)
- where escape '"' (b, str) = (True, '\\' : '"' : str)
- escape '\\' (True, str) = (True, '\\' : '\\' : str)
- escape '\\' (False, str) = (False, '\\' : str)
- escape c (b, str) = (False, c : str)
- -- See long comment above for what this function is trying to do.
- --
- -- The Bool passed back along the string is True iff the
- -- rest of the string is a sequence of backslashes followed by
- -- a double quote.
-
-#endif