https://github.com/jhedev/xml-conduit-generics

Library to create xml representation of data type based on xml-conduit and GHC Generics
https://github.com/jhedev/xml-conduit-generics

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Library to create xml representation of data type based on xml-conduit and GHC Generics

• Host: GitHub
• URL: https://github.com/jhedev/xml-conduit-generics
• Owner: jhedev
• License: mit
• Created: 2014-01-17T13:59:47.000Z (almost 11 years ago)
• Default Branch: master
• Last Pushed: 2014-01-17T14:21:44.000Z (almost 11 years ago)
• Last Synced: 2023-07-31T23:33:52.967Z (over 1 year ago)
• Language: Haskell
• Homepage:
• Size: 137 KB
• Stars: 0
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

        
xml-conduit-generics

====================

Small library based on xml-conduit to create xml representations for 

your own data types. It's just thrown together and still missing a few

default instances. 

#Example:

If we have a datatype like the following

```

data User = User { 

                   firstName :: String,

                   lastName :: String,

                   age :: Int,

                   hobbies :: [String]

                  }

                  deriving (Show, Generic)

```

With ```deriving Generic``` we let GHC derive the generic representations.

If we add

```

instance ToXml User

```

the compiler will create this instance for us. So let's create two users and

write the xml to a file

```

main :: IO()

main = do

        writeFile def { rsPretty = True } "users.xml" $ Document (Prologue [] Nothing []) root []

            where

                john = User "John" "Doe" 44 ["jokes", "laughing"]

                jane = User "Jane" "Doe" 38 []

                users = (toXml) john ++ (toXml jane)

                root = Element "users" empty users

```

This will create a users.xml file with the following content:

```

    

        

            John

        

        

            Doe

        

        

            44

        

        

            jokeslaughing

        

    

    

        

            Jane

        

        

            Doe

        

        

            38

        

        

    

```

You see there is a problem with the content of the hobbies tags. This is because the representation of 

a list is just the concatenation of the representation of the elements and a string is represented by its 

value. So this will just concat all strings in the list. To avoid this behaviour we create a simple

wrapper for our hobbies:

```

data Hobby = Hobby String deriving (Show, Generic)

instance ToXml Hobby

```

And change the user data type as follows:

```

data User = User { 

                   firstName :: String,

                   lastName :: String,

                   age :: Int,

                   hobbies :: [Hobby]

                  }

                  deriving (Show, Generic)

```

After updating john and jane to:

```

                john = User "John" "Doe" 44 [Hobby "jokes", Hobby "laughing"]

                jane = User "Jane" "Doe" 38 []

```

Now our xml file will look like this:

```

    

        

            John

        

        

            Doe

        

        

            44

        

        

            

                jokes

            

            

                laughing

            

        

    

    

        

            Jane

        

        

            Doe

        

        

            38

        

        

    

```