Context

We should explicitly evaluate whether PDEAlchemy should adopt, adapt, or expose an alternate API mode inspired by the PAY() / LOGPAY() abstractions in the OpenSourceRisk ecosystem.

This issue explicitly acknowledges the OpenSourceRisk repository and documentation at https://opensourcerisk.org and the OpenSourceRisk Engine codebase (OpenSourceRisk/Engine).

Why this matters

• PAY() in ORE ScriptedTrade combines payoff amount, discounting, FX-to-base conversion, and model numeraire handling in one semantic primitive.
• LOGPAY() extends this with cashflow logging side effects.
• PDEAlchemy currently uses explicit TOML/config-driven process + payoff definitions with separate reporting pathways.

Proposal to evaluate

1. Add a design note comparing current PDEAlchemy semantics vs ORE-style PAY() / LOGPAY() semantics.
2. Assess a pure PAY(...) abstraction in PDEAlchemy (no side effects) as an alternate authoring mode.
3. Assess whether LOGPAY-style behaviour should be handled separately in reporting/audit layers rather than in core pricing expressions.
4. Define migration/compatibility options so existing TOML flows remain stable.

Deliverables

• Recommendation memo in repo docs (adopt / partial adopt / reject).
• If adopted, an MVP design for:
  • syntax/API shape,
  • mapping to current pricing config schema,
  • validation and explain rendering implications,
  • test plan and trust-boundary impact.

Acceptance criteria

• Explicit statement of PDEAlchemy’s position on ORE-style PAY() / LOGPAY() semantics.
• Clear decision on whether to support this as an alternate API/framework mode.
• If supported, scoped implementation plan with phases and non-goals.