I'm sorry, but as a newby I can't seem to get it to work.
If I use
return (mtime :: Integer)
I get
src/Main.hs:21:13:
Couldn't match type ‘Foreign.C.Types.CTime’ with ‘Integer’
Expected type: Integer
Actual type: System.Posix.Types.EpochTime
In the first argument of ‘return’, namely ‘(mtime :: Integer)’
In a stmt of a 'do' block: return (mtime :: Integer)
If I use
return (toInteger mtime)
I get
src/Main.hs:21:13:
No instance for (Integral System.Posix.Types.EpochTime)
arising from a use of ‘toInteger’
In the first argument of ‘return’, namely ‘(toInteger mtime)’
In a stmt of a 'do' block: return (toInteger mtime)
In the expression:
do { status <- getFileStatus filepath;
let mtime = modificationTime status;
return (toInteger mtime) }
What am I doing wrong here? How would I pattern match to convert the type?
Greetings,
Bram
PS Code is still
https://github.com/bneijt/httpmtimeline/blob/master/src/Main.hs#L21
Versions
cabal-install version 1.22.2.0
using version 1.22.2.0 of the Cabal library
The Glorious Glasgow Haskell Compilation System, version 7.10.1
On Tue, Sep 15, 2015 at 6:48 PM, David Kraeutmann
EpochTime is an instance of Integral. You can just use toInteger :: Integral a => a -> Integer. On 9/15/2015 6:42 PM, Bram Neijt wrote:
Dear Haskell cafe,
I want to convert form
mtime :: System.Posix.Types.EpochTime
to something aeson can eat without having to define an instance. I choose Integer.
My current solution[1] is just using (read . show). I know, ugly, but the only thing I could get going.
What is the proper way to convert System.Posix.Types.EpochTime to Integer or something else aeson will automatically convert without making a ToJSON instance?
As a beginner I wonder: is there a general way to go about finding conversion paths between types?
Greetings,
Bram Neijt
[1] https://github.com/bneijt/httpmtimeline/blob/master/src/Main.hs#L21 _______________________________________________ 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