treerack/eskip.parser

/*
Eskip routing configuration format for Skipper: https://github.com/zalando/skipper
*/

eskip:root = (expression | definitions)?;

space:ws   = [ \n\b\f\r\t\v];
comment:ws = "//" [^\n]*;

decimal-digit:alias = [0-9];
octal-digit:alias   = [0-7];
hexa-digit:alias    = [0-9a-fA-F];

decimal:alias:nows = [1-9] decimal-digit*;
octal:alias:nows   = "0" octal-digit*;
hexa:alias:nows    = "0" [xX] hexa-digit+;
int                = decimal | octal | hexa;

exponent:alias:nows = [eE] [+\-]? decimal-digit+;
float:nows          = decimal-digit+ "." decimal-digit* exponent?
                    | "." decimal-digit+ exponent?
                    | decimal-digit+ exponent;

number:alias:nows = "-"? (int | float);

string:nows = "\"" ([^\\"] | "\\" .)* "\"";
regexp:nows = "/" ([^\\/] | "\\" .)* "/";
symbol:nows = [a-zA-Z_] [a-zA-z0-9_]*;

arg:alias  = number | string | regexp;
args:alias = arg ("," arg)*;
term:alias = symbol "(" args? ")";

predicate        = term;
predicates:alias = "*" | predicate ("&&" predicate)*;

filter        = term;
filters:alias = filter ("->" filter)*;

address:alias = string;
shunt         = "<shunt>";
loopback      = "<loopback>";
backend:alias = address | shunt | loopback;

expression = predicates ("->" filters)? "->" backend;

id:alias   = symbol;
definition = id ":" expression;

definitions:alias = ";"* definition (";"+ definition)* ";"*;