nyandere

Finally figure out how much everyone owes each other.

Installation

If Rust is already installed, just write cargo install nyandere! Otherwise check out the latest release.

Usage

Much like one would write an R, Julia or Python script to describe the processing some data, one can write a nyandere script like a receipt!

The syntax is inspired by SQL. It is case-sensitive, though.

A script usually consists of 3 phases: creation, transfer and analysis. See asset/examples/typical.nyan for a small typical script.

Creation

An actor is a stateful participant in an interaction. Each actor needs to be created before it can be used, this avoids errors due to typos or the works.

An actor is one of the following kinds:

• Entity: Holds a balance to other entities and can make deliveries, can be created via create entity <name>
• Concept: An off-the-shelf somewhat standardized product with a name, optionally a default price and optionally a GTIN. Can be created via create concept <name> (price <price>) (gtin <gtin>)
  • About the GTIN
    • Is a base10 number with no leading zeroes between 8 and 14 digits long (both inclusive)
    • Thought for use with a barcode scanner
    • There's cheap used ones connectable via USB
• Object: One physical object, possibly an instance of a concept. Can be created via create object <name> (parent <concept>)
• Product: A concept or object.

For example, this would create 2 entities A, B and a concept Multikey with the price of 1.70€ and the GTIN 10000000, as well as an object thing with Multikey as parent concept:

create entity A
create entity B
create concept Multikey price 1.70€ gtin 10000000
create object thing parent Multikey

A few more caveats:

• An object inherits its default price from its parent, if any.
• One can refer to a concept by its name or GTIN iff it's been specified at creation.
• Names and GTINs can be shadowed.
  • For example, one can create 2 concepts with the name cotton after each other, but only the last created one is accessible by that name.
  • However, the shadowed actors still exist. They aren't replaced. Existing transfers and parent relationships aren't changed by shadowing.
• Specifying products by name looks up objects before concepts.

Transfer

A transfer is one of:

• Payment of money from an entity to an entity via pay <money> from <entity> to <entity>
• Delivery of a product from an entity to an entity via deliver <product> (price <money>) from <entity> to <entity>
  • The price expresses what the source entity expects back from the target entity
  • It is a value debit expected back at some point, in a way
  • Has to be specified only if the product doesn't have a default price

Analysis

Look at what happened from a larger point of view.

• The balance between two entities is how much they owe each other. It is the deliveries (with expected values) and payments to each other summed up: balance from <entity> to <entity>

License

Please do note that while I do hope this is useful to some, this is a project created in my personal free time. I am not a professional, nor is this a product I am selling.

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.