Pidgin code
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In computer science, Pidgin Algol refers to an informal notation that mixes syntax taken from a programming language (traditionally ALGOL 60 or ALGOL 68) with mathematical notation, such as that of set theory. Hence the mixture is a sort of pidgin. It is used to describe algorithms at a level of detail where control structure is made explicit, while some data structures are still left at an abstract, programming-language-independent level.
A related notion is pseudocode.