embed

Overview ¶

Command embed is an example of a Go program that runs Kukel code (see docs/embedding.md): it prices orders, and the discount of each order comes from rules that users write as a Kukel script.

go run ./examples/embed examples/embed/rules.kkl examples/embed/orders.json

The script has a function discount(order), which gives the percentage off (0 to 50). It gets the order as a map, and a host module, shop, with what the rules may ask the Go program:

shop::customer(name)  the customer as a map: "name", "since" (a year),
                      "vip"; a KeyError for a customer the shop does not
                      know
shop::note(text)      adds text to the notes printed with the order
shop::year            the year now (a constant)

The script is not trusted: it may not read or write files or end the program (kukel.SystemBuiltins), may use only the modules json and strings, and each order gets a step limit and a time limit. A rule that fails, runs too long or gives a wrong discount fails only its order.

The exit code is 0, 1 when an order failed, 2 when the rules or the orders cannot be loaded.