This repository contains the follow up code from the course Functional Programming Principles in Scala I'm attending through Coursera. The course is available at https://www.coursera.org/learn/progfun1

Some of the topics I studied in this course are:

• Programming Paradigms
• Reasons to use Functional Programming
• Evaluation methods in Scala
  • Substitution model
  • call-by-name
  • call-by-value
• Short-circuit evaluation
• Tail Recursion

• High-Order Functions
• Currying
• Infix Notation
  • Relaxed Identifiers
  • Precedence Rules

• Persistent Data Structures
• Class Hierarchies
• Dynamic Binding
  • Dynamic method dispatch
• How classes are organized
  • packages and imports
  • single inheritance
  • Exceptions
• Polymorphism
  • Cons-Lists
  • Type Parameters
  • Type erasure

• Object-Oriented Programming in Scala
  • Creating classes to substitute primitive types
  • Peano numbers
  • Functions as Objects (trait with apply method)
  • Expansion of Function Values
  • Expansion of Function Calls
  • ETA-Expansion
• Polymorphism
  • subtyping and generics
  • bounds and variance
  • Type Bounds
    • upper bound: [S <: IntSet]
    • lower bound: [S >: NonEmpty] (so S could be one of NonEmpty, IntSet, AnyRef or Any)
    • mixed bounds: [S >: NonEmpty <: IntSet]
    • Covariance and Array typing problem (ArrayStoreException in Java)
  • Liscov Substitution Principle -> in Scala, Arrays are not covariant
• Variance
• Decomposition
  • better avoid using type tests and type casts in Scala (low-level and potentially unsafe)
  • Object-Oriented Decomposition (instead, one could use ⮌)
    • Limitations of OO Decomposition
• Pattern Matching
  • Functional Decomposition with Pattern Matching
  • Case Classes
  • Forms of Patterns and how match expressions are evaluated
• Lists
  • Constructors of List: Nil and :: (pronounced cons)
  • List operations and patterns

• More functions on Lists
  • last, init, concat, reverse, removeAt, flatten
• Pairs and Tuples
  • Sorting Lists faster with merge sort
  • the Tuple class
• Implicit Parameters
  • Parametrization with Ordering
• Higher-Order List Functions
• Reduction of Lists Extra credit:
• Reasoning about concat
  • structural induction
  • referential transparency
• A Larger Equational Proof on Lists
  • generalize the equation
  • fold/unfold method

• Other Collections
  • Vector
  • Collection Hierarchy
  • Range
• Combinatorial Search and For-Expressions
• Sets
• Maps
• Option Type