The Seven Foundational Programming Languages

Choosing a programming language can be daunting, but the key is to start somewhere, as the core concepts remain consistent across many languages. These fundamentals form the basis of what I call 'ur-languages', which are the foundational archetypes of modern programming languages. I identify seven such ur-languages: ALGOL, Lisp, ML, Self, Forth, APL, and Prolog.

## ALGOL

ALGOL is the oldest ur-language, characterized by sequences of assignments, conditionals, and loops organized into functions. It has influenced many languages, including C, Java, and Python. Its history traces back to Ada Lovelace and has evolved through structured programming to include features like classes and polymorphism.

## Lisp

Lisp is known for its prefix expressions and powerful macro system, allowing programmers to redefine language semantics. Originating from a mathematical question, Lisp has been pivotal in AI research and remains influential, with variants like Common Lisp and Clojure.

## ML

ML languages are functional, with first-class functions and a robust type system. They rely on recursion for iteration and have influenced languages like Haskell and OCaml. ML's roots are in theorem proving, and it remains popular in academic circles.

## Self

Self represents object-oriented languages where objects communicate via messages. Smalltalk and Self are key examples, with Smalltalk introducing classes and Self eliminating them for a purer object model. These languages have shaped modern OOP practices.

## Forth

Forth is a stack-based language, operating with a data stack and reverse Polish notation. It's highly customizable, allowing programmers to redefine its grammar. Forth is prevalent in embedded systems, with PostScript being a notable derivative.

## APL

APL is an array language with concise syntax for high-level operations on arrays. Its terse nature makes it powerful for complex calculations, influencing environments like MATLAB and NumPy.

## Prolog

Prolog is a logic programming language based on facts and queries. It has been used in AI and type checking, with a strong focus on efficient search algorithms. Despite its niche status, Prolog remains a valuable tool for certain applications.

Exploring these ur-languages broadens a programmer's perspective, offering new ways to solve problems. Learning languages from different ur-language families enriches one's programming toolkit, making it easier to adapt to new paradigms and technologies.