[Haskell-cafe] Newbie question on Haskell type

[robert dockins]

In GHC you can do this:

 > import Data.Typeable

 > isString :: (Typeable a) => a -> Bool
 > isString x = typeOf x == typeOf (undefined::String)

Why do you want this?  It's not the kind of operation one does very 
often in Haskell.


Huong Nguyen wrote:

> Hi all,
>  
> I want to write a small functionto test whether an input is a String or 
> not. For example,
>  
> isString::(Show a) =>a ->Bool
> This function will return True if the input is a string and return False 
> if not
>  
> Any of you have idea about that? Thanks in advance
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe