Bob

Instructions

Your task is to determine what Bob will reply to someone when they say something to him or ask him a question.

Bob only ever answers one of five things:

• "Sure." This is his response if you ask him a question, such as "How are you?" The convention used for questions is that it ends with a question mark.
• "Whoa, chill out!" This is his answer if you YELL AT HIM. The convention used for yelling is ALL CAPITAL LETTERS.
• "Calm down, I know what I'm doing!" This is what he says if you yell a question at him.
• "Fine. Be that way!" This is how he responds to silence. The convention used for silence is nothing, or various combinations of whitespace characters.
• "Whatever." This is what he answers to anything else.

You need to implement the responseFor function that returns Bob's response for a given input. You can use the provided signature if you are unsure about the types, but don't let it restrict your creativity:

responseFor :: String -> String

To solve this exercise you may read up on:

• Guards

This exercise works with textual data. For historical reasons, Haskell's String type is synonymous with [Char], a list of characters. For more efficient handling of textual data, the Text type can be used.

As an optional extension to this exercise, you can

• Read about string types in Haskell.

• Add - text to your list of dependencies in package.yaml.

• Import Data.Text in the following way:

  import qualified Data.Text as T
  import           Data.Text (Text)
  

• You can now write e.g. responseFor :: Text -> Text and refer to Data.Text combinators as e.g. T.isSuffixOf.

• Look up the documentation for Data.Text,

• You can then replace all occurrences of String with Text in Bob.hs:

  responseFor :: Text -> Text
  

This part is entirely optional.

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Source

Inspired by the 'Deaf Grandma' exercise in Chris Pine's Learn to Program tutorial.