01-Design-Thought-Process.md

Design Thought-Process

Note: one should read through this project's corresponding test folder's Test Thought-Process.md file as it further clarifies a few things said below.

Level 4 / Core

We'll first define the types we'll be using throughout our program. When I thought about this particular 'domain', I came up with these concepts:

Type Name	What it is	Properties/Purpose	Implementation
Bounds	The lower and upper int boundaries	Property: lower <= upper Purpose: insures the RandomInt and a player's Guess are within its bounds	A newtyped Record that exports only its smart constructor to insure correct instantiation. Helper functions also exist in the module, some of which are exported.
RandomInt	The random int the player is trying to guess	Property: x == lower or x == upper or lower < x < upper Once created, the value is read-only	A newtyped Int that exports only its smart constructor to insure correct instantiation and usage.
Guess	The guess the player makes	Property: same property as RandomInt in relation to Bounds Purpose: see whether it is equal to the game's RandomInt	A newtyped Int that exports only its smart constructor to insure correct instantiation. guessEqualsRandomInt function is also exported and usable via ==# infix notation.
RemainingGuesses	The remaining guesses the player has	The initial value should be positive The value can only decrease by one after an incorrect guess	A newtyped Int that exports only its smart constructor to insure correct instantiation. decrement function correctly reduces the wrapped Int by one and outOfGuesses checks whether the player can keep playing

Level 3 / Domain

A game consists of four stages:

1. explaining the rules
2. setting up the game
3. playing it (run the game loop until player wins/loses)
4. output whether the player won/lost

The following image is the general flow of the program:

Level 2 / API

The "effects" or "capabilities" we need to run this program are relatively simple:

• The capability to generate a random Int value (Note: this random number generator does not need cryptography-level security)
• The capability to send a message to the user
• The capability to get the user's input:
  • two Int values for the Bounds
  • one Int value for the RemainingGuesses
  • an n number of guesses

Level 1 / Infrastructure

Each of the above capabilities can be obtained by a few different things:

• The random number generation can be done via the Effect.Random (randomInt) function
• We can "send a message to the user" in one of three ways
  • (Production) Console-based approach: use Node.ReadLine
  • (Production) Web-based approach: use Halogen
  • (Test) this can be flat out ignored as its purely informative
• We can "get the user's input" in one of three ways:
  • (Production) Console-based approach: use Node.ReadLine
  • (Production) Web-based approach: use Halogen
  • (Test) provide the next input in a randomly-generated sequence of player guesses

Level 0 / Machine Code

Production: we'll use Aff to run the Node.ReadLine and Halogen code Test: we'll use Effect and QuickCheck to test our domain logic.

Code Warning

The browser-based UI you will see for this project will look utterly horrible! This is intentional because it makes the pattern to follow easier to see without CSS and additional events cluttering up the code base