Page "Block (programming)" Paragraph 2

Ideas of block structure were developed in the 1950s during the development of the first autocodes, and were formalized in the Algol 58 and Algol 60 reports.

Algol 58 introduced the notion of the " compound statement ", which was related solely to control flow.

The subsequent Revised Report which described the syntax and semantics of Algol 60 introduced the notion of a block, consisting of " A sequence of declarations followed by a sequence of statements and enclosed between begin and end ..." in which " very declaration appears in a block in this way and is valid only for that block.