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| -rw-r--r-- | doc/forum/howto_mapM_RevertableProperty.mdwn | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/doc/forum/howto_mapM_RevertableProperty.mdwn b/doc/forum/howto_mapM_RevertableProperty.mdwn new file mode 100644 index 00000000..7ebcbd47 --- /dev/null +++ b/doc/forum/howto_mapM_RevertableProperty.mdwn @@ -0,0 +1,52 @@ +Hello + +I have this kind of property + + myProperty :: Conf -> RevertableProperty NoInfo + + +now I have a [Conf] and I want to create also a RevertableProperty NoInfo which apply myProperty for each Conf + +I tried to find an equivalent of mapM for properties but I found nothing which works as expected. + +I tried with combineProperties but it failed also with a "cryptic message" +mpoints is the [Conf] + + + src/config.hs:250:17: + Couldn't match type `CInfo + (PropertyListType (Property [NoInfo])) + (PropertyListType (Property [NoInfo]))' + with `NoInfo' + Expected type: RevertableProperty NoInfo + Actual type: RevertableProperty + (CInfo + (PropertyListType (Property [NoInfo])) + (PropertyListType (Property [NoInfo]))) + In the expression: mount <!> umount + In an equation for `mountExp': + mountExp b + = mount <!> umount + where + mount + = combineProperties + "mount nfs files" (mapM mount'' mpoints) + umount + = combineProperties + "umount nfs files" (mapM umount'' mpoints) + mpoints + = [MountConf + "nfs" + ("ruche-" + ++ + beamline ++ ".mydomain.org:/" ++ beamline ++ "-users") + ("/nfs/ruche-" ++ beamline ++ "/" ++ beamline ++ "-users"), + ....] + beamline = show b + +What is the right way to create a RevertableProperty from a list of RevertableProperty + +thanks + +Frederic + |