Use Case

COBOL migration needs a bounded bridge, not a blind rewrite.

This use case focuses on lifting legacy logic into explicit PCD or constrained bounded outputs before transpilation or modernization.

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Use Case

Use cases stay operational: bounded workflow before implementation detail.

Each use case explains a real operator flow with explicit verification stages and bounded claims.

Scenario Evidence

The bounded workflow remains the main reference

The route highlights operator decision points and verification obligations before code details.

Primary object

Lifted blueprint

The key step is making legacy logic inspectable before replacing it.

Verification point

Post-lift

The useful check happens on the extracted circuit boundary.

Proof style

Migration dossier

The result should preserve enough structure for engineers to inspect the transformation.

Legacy extraction

Lift the existing logic first

Present PCD as a bridge that exposes what the legacy code actually computes.

Migration risk

Reduce translation ambiguity

The value comes from bounding the logic before it is moved, not from a generic modernization promise.

Reuse path

Connect the lifted result to the wider product

End in certification, review, and reuse rather than a one-off rewrite narrative.

Constraint Example

Anchor the scenario to a real policy or circuit sketch

Code is supporting evidence for the domain workflow and its boundaries.

Liftable domain

lift boundary

Show how legacy arithmetic or decision logic is extracted into explicit bounded objects.

Migration review

side-by-side review

Engineers should be able to compare source behavior and lifted behavior before any target code is emitted.

Scoped claim

bounded modernization

The use case does not imply that every legacy system becomes instantly certified end to end.

Bounded example

payroll.pcd

Φ_c = 1

PC compute_net_pay {
  input gross : Float64[0.0 .. 1e7]
  input tax   : Float64[0.0 .. 1e7]

  assert gross >= tax
  output net : Float64 = gross - tax
}

Use cases stay concrete and operator-readable, and they avoid overclaiming beyond visible constraints.

Workflow

The flow of proof stays explicit

Every use case makes clear how an engineer goes from source material to bounded output and published evidence.

Lift or express

Start from source code or from an explicit PCD or policy sketch.

Check boundaries

Run domain checks and closure analysis before the result is trusted.

Emit evidence

Emit diagnostics, certification state, and a reusable bounded output.

Reuse the result

Feed the bounded result back into the platform, registry, or delivery flow.

Keep the workflow legible without implying every downstream organizational control is solved by this workflow.

Show the bounded migration bridge.

The strongest signal is a lift-review-certify path that makes legacy logic inspectable before it is moved.

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