Railroad

railroad-ebnf-beta
title "Arithmetic Expression Grammar"

expression = term ( ( "+" | "-" ) term )* ;
term = factor ( ( "*" | "/" ) factor )* ;
factor = number | "(" expression ")" ;
number = digit+ ;
digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;

Syntax

• railroad-ebnf-beta reads EBNF: rule = … ; with | for choice, ( ) to group, and *, + and ? to repeat.
• railroad-peg-beta reads PEG: rule <- … ; with / for choice.
• railroad-beta reads combinators: sequence(…), choice(…), zeroOrMore(…), oneOrMore(…), terminal("…") and nonterminal("…").
• title names the diagram; each rule is a track.