Struct WithholdingGenerator 

pub struct WithholdingGenerator { /* private fields */ }

Generates withholding tax records for cross-border vendor payments.

For each payment where vendor_country != source_country:

• Looks up the treaty rate for the (source_country, vendor_country) pair.
• If a treaty exists, applies the treaty rate.
• If no treaty exists, applies the default withholding rate.
• Computes withheld_amount = base_amount * applied_rate.

Domestic payments (where vendor_country == source_country) are excluded from withholding and produce no records.

Standard Treaty Rates

The with_standard_treaties method loads a US-centric treaty network with service withholding rates for major trading partners (GB, DE, JP, FR, SG, IN, BR).

Implementations

impl WithholdingGenerator

pub fn new(seed: u64, default_rate: Decimal) -> Self

Creates a new withholding generator with the given seed and default rate.

The default rate is applied when no treaty rate exists for a given country pair. A common value is 0.30 (30%).

pub fn add_treaty_rate( &mut self, source_country: &str, vendor_country: &str, rate: Decimal, )

Adds a treaty rate for a specific country pair.

The rate is stored for the (source_country, vendor_country) direction. Treaty rates are directional: a US-DE treaty rate applies when the US is the source and DE is the vendor, but not vice versa.

pub fn with_standard_treaties(self) -> Self

Loads the standard US treaty network for service withholding rates.

Treaty rates (service withholding, US perspective):

• US-GB: 0% (services)
• US-DE: 0% (services)
• US-JP: 0% (services)
• US-FR: 0% (services)
• US-SG: 0% (services)
• US-IN: 15% (services)
• US-BR: 15% (services)

pub fn generate( &mut self, payments: &[(String, String, String, Decimal)], source_country: &str, ) -> Vec<WithholdingTaxRecord>

Generate withholding records for cross-border payments.

Each payment is a tuple of (payment_id, vendor_id, vendor_country, amount). Domestic payments (where vendor_country == source_country) are excluded.

For each cross-border payment:

• If a treaty rate exists for (source_country, vendor_country), the treaty rate is applied.
• Otherwise the default_rate is applied.
• withheld_amount = base_amount * applied_rate.