snit::type a_pe_grammar {
    constructor {} {
        install myg using pt::peg::container ${selfns}::G
        $myg start {n Expression}

        $myg add   AddOp
        $myg mode  AddOp      value
        $myg rule  AddOp      {/ {t -} {t +}}

        $myg add   Digit
        $myg mode  Digit      value
        $myg rule  Digit      {/ {t 0} {t 1} {t 2} {t 3} {t 4} {t 5} {t 6} {t 7} {t 8} {t 9}}

        $myg add   Expression
        $myg mode  Expression value
        $myg rule  Expression {/ {x {t \50} {n Expression} {t \51}} {x {n Factor} {* {x {n MulOp} {n Factor}}}}}

        $myg add   Factor
        $myg mode  Factor     value
        $myg rule  Factor     {x {n Term} {* {x {n AddOp} {n Term}}}}

        $myg add   MulOp
        $myg mode  MulOp      value
        $myg rule  MulOp      {/ {t *} {t /}}

        $myg add   Number
        $myg mode  Number     value
        $myg rule  Number     {x {? {n Sign}} {+ {n Digit}}}

        $myg add   Sign
        $myg mode  Sign       value
        $myg rule  Sign       {/ {t -} {t +}}

        $myg add   Term
        $myg mode  Term       value
        $myg rule  Term       {n Number}

        return
    }

    component myg
    delegate method * to myg
}
