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Patternia v0.6.2 Release Note

Release Date: December 23, 2025 Version: 0.6.2

Overview

Patternia v0.6.2 tightened compile-time feedback for incomplete matches.

This page has been normalized to the current API surface. The original release note described [[nodiscard]] on the old builder object; the same idea now applies to the pipeline match context.

Highlights

Incomplete Match Diagnostics

Ignoring a partially formed match is diagnosed so unfinished expressions do not silently disappear.

using namespace ptn;

void run(int value) {
  match(value);
  // warning: incomplete match expression
}

The intended form is to finish the match by piping an on(...) case pack:

using namespace ptn;

int classify(int value) {
  return match(value) | on(
    lit(1) >> 1,
    _ >> 0
  );
}

Safety Direction

This release reinforced a project rule that remains active:

  • an unfinished match expression should be noisy
  • diagnostics should tell users the next valid step
  • API misuse should fail at compile time, not at runtime

Historical Note

The original v0.6.2 note explained the warning in terms of a chained builder that was later removed. Current code still gets the same safety signal through the pipeline context returned by match(subject).