Re: [Haskell-cafe] ????Pattern match(es) are overlapped???
I actually ended up using a lookup list e.g. handlers=[(getMethod,doGet),(putMethod,doPut)] which has the convenience of being able to put a 501 "Not Implemented" in an obvious place. I'll post the code shortly. My goal is to form the core of a generically useful HTTP haskell server library. -Alex- On Mon, 22 Mar 2004, Ketil Malde wrote: > "Arjan van IJzendoorn" <[EMAIL PROTECTED]> writes: > > >>newtype Method = Method String > >>getMethod = Method "GET" > >>putMethod = Method "PUT" > >>doMeth getMethod = ... > >>doMeth putMethod = ... > > > You will have to write: > > > > doMeth (Method "GET") = ... > > doMeth (Method "PUT") = ... > > Or (I assume, haven't tested) if you insist on renaming the methods: > > doMeth m | m == getMethod = ... >| m == putMethod = ... > > (or using a case statement, of course) > > -kzm > -- > If I haven't seen further, it is by standing in the footprints of giants > _ S. Alexander Jacobson mailto:[EMAIL PROTECTED] tel:917-770-6565 http://alexjacobson.com ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
RE: [Haskell-cafe] ????Pattern match(es) are overlapped???
Hi, > Or (I assume, haven't tested) if you insist on renaming the methods: > > doMeth m | m == getMethod = ... >| m == putMethod = ... This, of course, assumes that you've derived (or declared) Method an instance of Eq. Regards, Stefan ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ????Pattern match(es) are overlapped???
"Arjan van IJzendoorn" <[EMAIL PROTECTED]> writes: >>newtype Method = Method String >>getMethod = Method "GET" >>putMethod = Method "PUT" >>doMeth getMethod = ... >>doMeth putMethod = ... > You will have to write: > > doMeth (Method "GET") = ... > doMeth (Method "PUT") = ... Or (I assume, haven't tested) if you insist on renaming the methods: doMeth m | m == getMethod = ... | m == putMethod = ... (or using a case statement, of course) -kzm -- If I haven't seen further, it is by standing in the footprints of giants ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] ????Pattern match(es) are overlapped???
>newtype Method = Method String >getMethod = Method "GET" >putMethod = Method "PUT" > >[...] > >doMeth getMethod = ... >doMeth putMethod = ... For Haskell the last two lines look both like pattern-matching on a variable which always matches. You might as well have written: doMeth x = ... doMeth y = ... There is no macro facility in Haskell so you cannot give patterns a name like you do in line 2 and 3. You will have to write: doMeth (Method "GET") = ... doMeth (Method "PUT") = ... Good luck, Arjan ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ????Pattern match(es) are overlapped???
I am implementing HTTP and I have something like: newtype Method = Method String getMethod = Method "GET" putMethod = Method "PUT" [...] doMeth getMethod = ... doMeth putMethod = ... GHC gives me a patter matches are overlapped warning. And when I run, I discover that pattern matching is not actually happening. getMethod is always executed even though the method passed is putMethod What am I doing wrong? -Alex- _ S. Alexander Jacobson mailto:[EMAIL PROTECTED] tel:917-770-6565 http://alexjacobson.com ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe
