Algol

ALGOL, short for Algorithmic Language, is a family of imperative programming languages designed for expressing algorithms in a precise way. The most influential members are ALGOL 60 (1960) and ALGOL 68 (1968). The family helped establish block structure, lexical scoping, and the use of a formal grammar to specify syntax, shaping the direction of language design in computing.

Origins and design: ALGOL emerged from an international collaboration of researchers in the late 1950s to provide a standard notation for algorithm description. ALGOL 60 introduced block structure with nested scopes, enabling declarations and statements to be grouped in blocks. It supported recursion, arrays, records, and procedures, and featured pass-by-name parameter passing for procedures, allowing delayed evaluation of arguments.

Impact and legacy: ALGOL 60 became the de facto standard for publishing algorithms in academic literature, papers, and textbooks. Its formal syntax, often described with a grammar akin to Backus–Naur notation, influenced many later languages and established core concepts such as structured programming, lexical scoping, and modular design.

ALGOL 68: A later revision aimed at a more powerful and orthogonal design, with a richer type system and a highly regular syntax. While ALGOL 68 had substantial influence on language theory and compiler construction, it saw less widespread adoption than ALGOL 60. Nevertheless, its ideas contributed to the development of subsequent languages and formal specification techniques.