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Top-Down Parsing Language (TDPL) is a type of formal grammar developed by Alexander Birman in the early 1970s. Birman originally named his formalism the TMG Schema (TS), but it was later given the name TDPL by Aho and Ullman in their “The Theory of Parsing, Translation and Compiling”.

See The TMG recognition schema, Alexander Birman, 1970

While PEGs provide a rich set of operators for constructing grammars, they are reducible to two minimal recognition schemas developed around 1970, TS/TDPL and gTS/GTDPL, which are here proven equivalent ineffective recognition power.