Top-down parsing language

Top-Down Parsing Language (TDPL) is a type of analytic formal grammar developed by Alexander Birman in the early 1970s in order to study formally the behavior of a common class of practical top-down parsers that support a limited form of backtracking. Birman originally named his formalism the TMG Schema (TS), after TMG, an early parser generator, but the formalism was later given the name TDPL by Aho and Ullman in their classic anthology The Theory of Parsing, Translation and Compiling. Top-Down Parsing Language (TDPL) is a type of analytic formal grammar developed by Alexander Birman in the early 1970s in order to study formally the behavior of a common class of practical top-down parsers that support a limited form of backtracking. Birman originally named his formalism the TMG Schema (TS), after TMG, an early parser generator, but the formalism was later given the name TDPL by Aho and Ullman in their classic anthology The Theory of Parsing, Translation and Compiling. Formally, a TDPL grammar G is a tuple consisting of the following components: A TDPL grammar can be viewed as an extremely minimalistic formal representation of a recursive descent parser, in which each of the nonterminals schematically represents a parsing function. Each of these nonterminal-functions takes as its input argument a string to be recognized, and yields one of two possible outcomes: