Programming Paradigms Lab 6-Higher-order functions and ADTs Solved

Lab 6. Higher-order functions and ADTs

Outline

• ●  Higher-order functions and lists in Haskell recap
• ●  User-defined types in Haskell recap
• ●  Exercise: N-body simulation

Rendering a tilemap

Exercise 6.1.

See prepared code snippet: https://code.world/haskell#PVe5pLviXrxL2FkIRKQ2SQw Implement function renderGrid that renders a Grid of Pictures.
Try using higher-order functions.

Rendering a tilemap (with ADTs)

Exercise 6.2.

See prepared code snippet: https://code.world/haskell#PuRiYbTd_q_icJ2rAyaP6tw Implement functions renderItem, renderTile.

-- | An item that can be placed on a floor tile.

data

= Key |

— | A tile.

data

= | |

-- ^ A key for some door.
-- ^ A coin.

        -- ^ A wall tile.
        -- ^ A floor tile, possibly with some item on it.
        -- ^ A door (with its index).

Item

DoorId

Coin

Tile

Wall

Floor

(Maybe Item)

Door

DoorId

Rendering a tilemap (with ADTs)

Exercise 6.3.

See prepared code snippet: https://code.world/haskell#PuRiYbTd_q_icJ2rAyaP6tw Implement function renderTileGrid.

-- | An item that can be placed on a floor tile.

data

= Key |

— | A tile.

data

= | |

-- ^ A key for some door.
-- ^ A coin.

        -- ^ A wall tile.
        -- ^ A floor tile, possibly with some item on it.
        -- ^ A door (with its index).

Item

DoorId

Coin

Tile

Wall

Floor

(Maybe Item)

Door

DoorId

Modifying a tilemap (with ADTs)

Exercise 6.4.

See prepared code snippet: https://code.world/haskell#PuRiYbTd_q_icJ2rAyaP6tw Implement function removeItems that removes items from all Floor tiles
in a Grid of Tiles.

Exercise 6.5.

Implement function mapGrid that applies a given function to every element in a Grid.

Exercise 6.6.

See prepared code snippet: https://code.world/haskell#PuRiYbTd_q_icJ2rAyaP6tw Implement function openDoors that opens all Door tiles (i.e. replaces them
with Floor tiles) in a Grid of Tiles.

Playing with a tilemap

Exercise 6.7.

See prepared code snippet: https://code.world/haskell#PuRiYbTd_q_icJ2rAyaP6tw Implement function myTileGrid2 by converting myCharGrid.

Exercise 6.8. (*)

Use activityOf to make the game interactive.

Homework (self-study)

1. Install Haskell https://www.haskell.org/downloads/
2. Read Learn you a Haskell for Great Good Chapters 2, 4, and 5

   http://learnyouahaskell.com/chapters

3. Test yourself by implementing a program that renders a Koch snowflake of a given rank in Haskell on Code.World platform (https://code.world/haskell):