Problem Sheet for LI Functional Programming - Week 5 & 6

Directories

Consider the following data type for directories.

data File = File {
  fileName :: String,
  contents :: String
  } deriving Show

data Directory = Directory {
  dirName :: String,
  subdirs :: [ Directory ],
  files :: [ File ]
  } deriving Show

Create your own sample directory structure
Write a function to return a list of all the files.
Here is a function to find a substring and return its index:
```
import Data.List

findString :: (Eq a) => [a] -> [a] -> Maybe Int
findString search str = findIndex (isPrefixOf search) (tails str)
```
Write a function to search the directory for a file containing some string.
Write a function to search for files by name
Modify the File type to contain different types of data: binary (you may wish to look at ByteString from the Haskell prelude) and string. Write functions to find all binary or text files in the given director structure.
Write a function to sort the directory contents alphbetically.
Harder Write a function to print the directory contents as a text tree.

XML

Consider the following simplified data type for representing XML documents:

data Element  = Element {
                  elName      :: String,
                  elAttribs   :: [Attr],
                  elContent   :: [Content]
                } deriving Show

data Content  = Elem Element
              | Text String
                deriving Show

data Attr     = Attr {
                  attrKey :: String,
                  attrVal :: String
                } deriving (Eq, Show)

Encode the following example:

<person gender="female">
  <firstname>Anna</firstname>
  <lastname>Smith</lastname>
</person>

Encode the following example:

<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>

Write a function which returns all elements containing only text in their content
Write a function which returns all elements which have exactly one child element
Write a function which searches for all elements with a given attribute key
Write a function which formats the XML data to a string
Harder Write a function to parse XML text to the above data type

You can continue with examples like the above by inventing your own transformations and queries on the directory and XML examples. Be creative!

Problem Sheet for LI Functional Programming - Week 5 & 6

Directories​

XML​

Directories

XML