UnitPrice

A price per an amount of a quantity, a choice by the quantity's kind, as the UK's Price Marking Order prices goods by weight, volume, length and area: shown £2.50/1 kg. Neither the price nor the amount is below 0.

Money and banking; not ordered; since Jadpo 0.1.0.

Make one

Pick one of its variants and give its fields, UnitPrice.per_mass { price: ... per: ... }.

Variants

Text, JSON and storage

It has no single text form, so text.from and text.parse don't take it. JSON sends an object of its variant's name, as tag, and the variant's fields.

It is stored in 4 columns, each named for the field, _ and its suffix. This is {"tag":"per_volume","price":{"amount":180,"currency":"GBP"},"per":{"value":"0.001","unit":"cubic_metre"}}:

Shown to people

text.format(value, locale:) shows it to people in their locale.

With locale: Locale.en_gb:

Operations

It has the contract's own operations: text.format, json.read, json.write and ==. It isn't ordered, so < and sorting don't take it. Every standard type meets one contract says how they work.