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User mostly interacts with Grammar and Patt types, declared in src/hparse/grammars.nim. DSL generates to list of constructor calls to oneP, orP etc.

Instantiation of the grammar consists of two parts - first one (initGrammarCalls) declares some helper constructors (mostly dslTok for token construction). Second part - initGrammarImpl converts DSL into array of pairs like { "Nonterm" : <constructor-calls> }. Template rule calls are inline in this constructor.

let nt = nterm[NoCategory, string]
proc dslTok(lex: string): auto = tok[NoCategory, string](
  catNoCategory, lex)

discard expandMacros:
  initGrammarImpl:
    List ::= "[" & Elements & "]"
    Elements ::= Element & @*(!"," & Element)
    Element ::= "," | List

DSL macro generates grammar literal, that can be converted into parser. Codegen-based parsers accept it as-is. For table-driven parsers you need to convert grammar literal to actual Grammar object, using toGrammar() function.

How parser construction is performed differs a lot for codegen and runtime parsers.

Codegen parser construction

Runtime parser construction