connascence-guide

Connascence: a Precise Coupling Vocabulary

Grade a seam by naming its worst coupling and its strongest connascence, then weaken or localize it — "tight/loose" is unactionable.

Essentials

• Name the connascence, don't say "tight" - classify the form and rate strength/locality/degree, see references/connascence.md
• Two moves: weaken and localize - rule of degree (strong→weak forms) and rule of locality (distance→weakness), see references/connascence.md
• Push every seam down the coupling ladder - content→common→control→stamp→data, worst to best, see references/coupling-ladder.md
• Aim for functional cohesion - one job per module; temporal cohesion is the package-by-layer trap, see references/cohesion-ladder.md
• Don't reach through strangers - Law of Demeter as the call-site detector for content coupling, see references/law-of-demeter.md

Gotchas

• "Tightly coupled" is not actionable — name the connascence form and the coupling rung, then you know the fix.
• Strong connascence is fine inside one module; it's only a problem across a boundary (rule of locality).
• Control coupling hides as configuration — a behavior flag passed into a shared function recouples its callers; split into two functions.
• Law of Demeter is a heuristic, not a law — fluent builders and pure data pipelines are deliberate exceptions; it targets reaching through a stranger to depend on or mutate its internals.
• Coupling and cohesion trade off — splitting a module to "loosen coupling" can shred its cohesion; grade both before cutting.

Example

SEAM   a billing function reaches into an Order's private `total` field
GRADE  content coupling (reaches internals) + connascence of meaning across a boundary
FIX    Order exposes a neutral `amountDue()` value (rule of degree → data coupling);
       billing reads the value — agreement is now named, local, and weak

Progressive Disclosure

• Read references/connascence.md - Load when classifying a coupling (static/dynamic forms, strength/locality/degree, the two rules)
• Read references/coupling-ladder.md - Load when grading or improving a seam by the content→data ladder
• Read references/cohesion-ladder.md - Load when judging whether a module's parts belong together, or spotting temporal cohesion
• Read references/law-of-demeter.md - Load when a call site reaches through returned objects (train wrecks)