It simplifies debugging by ensuring that all function arguments are fully evaluated before the function body is executed.

It forces all side effects to be evaluated in a predictable, linear order.

It requires all types to be explicitly annotated, as the compiler cannot infer them before evaluation.

It enables the creation of infinite data structures and avoids unnecessary computations by evaluating expressions only when their results are required.

A new function of type Int -> Int that is waiting for its final argument.

A 'thunk', an unevaluated expression that will compute an Int when forced.

A tuple containing the integer 5 and a function pointer.

Type error, because the function requires two arguments.

Product Type

Type Class

Sum Type

Recursive Type

False

True

A data type can only be an instance of a single type class.

Type classes can only be implemented for built-in types like Int and String.

Type classes require manual runtime type checking to ensure correctness.

Instances can be defined separately from the data type definition, allowing developers to extend types from external libraries with new behaviors.

To define a mapping for functions over a structure (like a list or Maybe) without altering the structure itself.

To convert a value into a string representation.

To provide a way to sequence computations that have side effects.

To define an equality check (==) for custom data types.

Its ability to handle dependent computations, where the result of one action determines the next action.

Its ability to apply a function wrapped in a context to a value wrapped in a context, enabling operations on multiple independent 'effectful' values.

Its ability to define a neutral element or 'empty' value for a context.

Its ability to model non-determinism using the list context.

The bind operator (>>=).

The function application operator ($).

The function composition operator (.).

The fmap operator from the Functor class.

Executing all side effects in a separate, non-functional thread.

Representing a side-effectful computation as a pure value. The Haskell runtime is then responsible for interpreting and executing this value.

Allowing side effects only within functions marked with the unsafe keyword.

Using a global state variable to track the state of the 'world'.

It can only be used for read-only state, similar to a Reader monad.

It uses a special compiler flag to allow mutable variables within a specific scope.

It directly wraps the IO monad to write state changes to a temporary file.

It is a function that takes an initial state and returns a tuple containing the result and the final state, with monadic bind chaining these functions together.

Create a single, massive data type that includes fields for configuration, potential errors, and IO actions.

Abandon purity and use unsafePerformIO to read the configuration and handle errors.

Write deeply nested do blocks, manually passing the configuration and checking for errors at each step.

Use a Monad Transformer stack, such as ReaderT Config (ExceptT String IO) a.

The use of floating-point numbers within a data constructor.

Constructors to be defined in separate modules from the data type itself.

Data constructors to explicitly define their return type, which can constrain type variables.

An infinite number of constructors for a single data type.