EBNF for FoxyCart discount strings

discounts.factor

USE: peg.ebnf

#! throw this in the listener to see the example parse tree

"discount_quantity_amount=Discount_Name{repeat|1-5.42|2-5|6-0}"
 
[EBNF
number   = [0-9]+  => [[ string>number ]]
amount   = number ("." number)?
type     = "allunits" | "incremental" | "repeat" | "single"
tier     = number "-" amount
method   = "discount" "_" ("quantity" | "price") "_" ("amount" | "percentage")
name     = [A-Za-z0-9_ ]+ => [[ >string ]]
discount = method "=" name "{" type "|" tier ( "|" tier )+ "}"
EBNF]

#! example parse tree
V{
    V{ "discount" "_" "quantity" "_" "amount" }
    "="
    "Discount_Name"
    "{"
    "repeat"
    "|"
    V{ 1 "-" V{ 5 V{ "." 42 } } }
    V{
        V{ "|" V{ 2 "-" V{ 5 f } } }
        V{ "|" V{ 6 "-" V{ 0 f } } }
    }
    "}"
}