I appreciate | as OR because (like its non-ascii cousin ∨) it uses an lr-symmetric glyph to denote a commutative operation. EDIT: Backus uses the asymmetric ov

I appreciate | as OR because (like its non-ascii cousin ∨) it uses an lr-symmetric glyph to denote a commutative operation. EDIT: Backus uses the asymmetric overbarred "or" in 1959, but by 1963 the | we know and love has already taken its place (that ASCII standardisation didn't start until 1961 may have something to do with this?) https://www.softwarepreservation.org/projects/ALGOL/paper/Backus-Syntax_and_Semantics_of_Proposed_IAL.pdf https://www.softwarepreservation.org/projects/ALGOL/paper/Ba... https://dl.acm.org/doi/pdf/10.1145/366193.366201 https://dl.acm.org/doi/pdf/10.1145/366193.366201