Functions you do not have to write again.
Functional Weave is a registry of capabilities. A capability is one function, implemented in TypeScript, Python and Rust, pinned by one set of test vectors that all three must pass. Install it into your project as readable source, not a black box.
finance.tax.add-vat
9 tests, 3 languages, one answer
| 20 percent on 100 pounds | £100.00, GB, STANDARD, 2026-09-16 | → | net £100.00, tax £20.00, gross £120.00, rate 20% |
| rounds a fractional penny up | £1.99, GB, STANDARD, 2026-09-16 | → | net £1.99, tax £0.40, gross £2.39, rate 20% |
| zero rated goods are taxable at nothing | £100.00, GB, ZERO, 2026-09-16 | → | net £100.00, tax £0.00, gross £100.00, rate 0% |
ts typescript py python rs rust
442 capabilities
656 published versions
13,578 tests
1 organisations
11 installs
Recently published
hospitality.bill-split
Split a restaurant bill evenly, by item or by share, exactly to the penny, with the service charge shared in proportion.
bill_split in Rust
money.split-even
Split an amount into n near-equal parts that add back up to exactly the whole.
split_even in Rust
agri.fertiliser-application
Fertiliser product rate (kg/ha and total) to meet N, P2O5 and K2O targets from its analysis, limiting nutrient first.
fertiliser_application in Rust
finance.proration
Split an amount into the part used and the part unused over a billing period, losing nothing.
prorate in Rust
agri.feed-ration
Ration costing and dry matter intake from each feed's fresh weight, DM % and price per tonne, in exact money.
feed_ration in Rust
agri.field-area
Field area in square metres, hectares and acres from a boundary polygon of latitude/longitude points.
field_area in Rust
agri.gross-margin
Enterprise gross margin (output less variable costs), in total and per hectare or per head, in exact money.
gross_margin in Rust