When you just run "cabal", it runs from some directory X; but it installs new cabal in some other directory Y. Sorry, I'm not an expert in Windows paths; but as of now you have two versions of cabal.exe installed: one old, which runs, and another, which is new. Отправлено с iPad

12 июля 2015 г., в 21:58, David Gladstein написал(а):

I have C:\Users\David\AppData\Roaming\cabal\bin on my path, and I have the same problem. I think it's been that way for years.

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On Sun, Jul 12, 2015 at 10:30 AM, Michael Snoyman wrote: You probably don't have $APPDATA\cabal\bin on your PATH

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On Sun, Jul 12, 2015 at 10:28 AM KC wrote: On Windows after I install the new cabal-install then when I do a cabal update it says there is a new cabal-install available.

Yet cabal-install installed without any errors.

Why do I get this message?

-- --

Sent from an expensive device which will be obsolete in a few months! :D

Casey

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The order of the paths matter, if the Haskell platform path is before the cabal one, any common programs will be shadowed. Run 'where.exe <program name>' to find out the path of the program that is first in line. Niklas ----- Ursprungligt meddelande ----- Från: "David Gladstein" Skickat: ‎2015-‎07-‎12 21:58 Till: "Michael Snoyman" Kopia: "haskell-cafe" Ämne: Re: [Haskell-cafe] On Windows after I install the new cabal-installthen when I do a cabal update it says there is a new ... I have C:\Users\David\AppData\Roaming\cabal\bin on my path, and I have the same problem. I think it's been that way for years. On Sun, Jul 12, 2015 at 10:30 AM, Michael Snoyman wrote: You probably don't have $APPDATA\cabal\bin on your PATH On Sun, Jul 12, 2015 at 10:28 AM KC wrote: On Windows after I install the new cabal-install then when I do a cabal update it says there is a new cabal-install available. Yet cabal-install installed without any errors. Why do I get this message? -- -- Sent from an expensive device which will be obsolete in a few months! :D Casey _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe

2015-07-13 18:41 GMT+02:00 Michael Steele :

On Windows the 'system' path variable always has precedence over the 'user' path variable (see [1]). You will need to rename, delete, or overwrite the version of cabal.exe installed globally for the one under %appdata% to be used.

[1]: https://support.microsoft.com/en-us/kb/100843

To me that looks like a bug in the Haskell Platform installer: It puts the path to the tools shipped with the platform into the the system PATH and the path to the user-installed tools (i.e. the stuff below %APPDATA%) into the user part of the PATH. This way, you will always get the shipped alex/cabal/happy/HsColour, not the new stuff. This is a bit like putting e.g. /usr/bin before your $HOME/bin on *nices, which is exactly the wrong way round. Furthermore, I've just seen that there is a 'C:\Program Files\Haskell\bin' at the start of my system PATH, pointing to nowhere. Is this a remnant of former GHC/platform installations? No clue where this comes from...

I created a Cabal variable with the path to cabal\bin in the system variables area and than put that early in the Path variable Cabal update now finds the new cabal-install What are the pros and cons of doing this? I have a feeling running batch scripts to set path variables might be better to avoid long path variables and to inadvertently finding the wrong files on long path variables. I have also found that you want to install most/all programming platforms outside of the Program Files folder which Windows has special protections on. -- -- Sent from an expensive device which will be obsolete in a few months! :D Casey On Jul 13, 2015 10:57 AM, "Michael Steele" wrote:

I disagree that this is a bug or misfeature in the Haskell Platform. The problem is caused by a quirk in how Windows works.

There are a few other options I didn't mention. One is to delete the global entry from the 'system' path variable and insert it into the 'user' path variable somewhere after the "%appdata%\cabal\bin" entry. The downside here is that other user accounts will be affected. Another option is to use a custom shortcut or execute a batch script which manually sets PATH variables as needed. This is the method I use personally.

On Mon, Jul 13, 2015 at 10:01 AM, Sven Panne wrote:

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2015-07-13 18:41 GMT+02:00 Michael Steele :

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On Windows the 'system' path variable always has precedence over the 'user' path variable (see [1]). You will need to rename, delete, or overwrite the version of cabal.exe installed globally for the one under %appdata% to be used.

[1]: https://support.microsoft.com/en-us/kb/100843

To me that looks like a bug in the Haskell Platform installer: It puts the path to the tools shipped with the platform into the the system PATH and the path to the user-installed tools (i.e. the stuff below %APPDATA%) into the user part of the PATH. This way, you will always get the shipped alex/cabal/happy/HsColour, not the new stuff. This is a bit like putting e.g. /usr/bin before your $HOME/bin on *nices, which is exactly the wrong way round.

Furthermore, I've just seen that there is a 'C:\Program Files\Haskell\bin' at the start of my system PATH, pointing to nowhere. Is this a remnant of former GHC/platform installations? No clue where this comes from...

-- -- Michael Steele