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Developer tools · #purescript
Goal We want to ensure that a rollback routine executed via Aff.bracket or Aff.try runs even if the Aff is cancelled before completion, such as during a schema migration that aborts due to a conflict. Current Observation When an Aff is cancelled using Async.cancelUnless , the release action supplied to bracket may not execute, leaving the database in an inco
PureScript’s type checker validates PureScript modules, but the Foreign Function Interface treats imported JavaScript as opaque. A foreign import can declare a precise PureScript type while the underlying JavaScript returns null, undefined, or an unexpected object shape, and the compiler accepts the mismatch without complaint. The resulting failure appears o
Concurrency in the Aff Monad PureScript manages asynchronous operations through the Aff monad, which leverages the JavaScript event loop to handle non-blocking I/O. While primitives like parallel and race allow multiple computations to initiate concurrently, the underlying execution remains single-threaded. Resource Contention and Scheduling When deploying a
Goal Determine whether the Eff monad or the Effect monad provides clearer, actionable type‑level information for diagnosing intermittent connection‑pool exhaustion in a service that experiences bursty load. Constraints and uncertainty The Eff monad (purescript‑eff) tracks individual effects via extensible rows, giving fine‑grained visibility of which allocat
When using PureScript's Aff monad, a timeout implemented with Aff.timeout cancels the underlying fiber and runs its finalizers before returning a Left (Error \"Timeout\") result. The goal is to understand whether this cancellation behaves as an immediate asynchronous interrupt that can skip synchronous, effect‑free sections, or as a synchronous operation tha
Goal: paginate a large dataset fetched via purescript-affjax while minimizing temporary memory allocation during slicing operations. Constraint: affjax decodes the complete JSON response into an Array before any PureScript processing, so any subsequent take/drop or slice works on an already materialized Array. Uncertainty: whether using Data.Array.slice (whi
Goal We want a seamless way to call a JavaScript function that returns a Promise from PureScript, automatically mapping it to PureScript’s Effect or Async monad. Current Constraints The foreign import syntax treats imported values as raw JavaScript, so a Promise returned by the imported function is passed through untouched. There is no automatic conversion;
Incremental JavaScript-to-PureScript migration with a shared FFI boundary I am migrating a small browser application from plain JavaScript to PureScript one module at a time, and both sides must keep running together in production during the transition. The plan is to wrap the remaining JavaScript modules behind foreign import declarations so new PureScript
Goal: achieve deterministic builds for a PureScript project that calls JavaScript via FFI. Constraint: Spago’s Dhall lockfile guarantees exact PureScript package versions but does not capture the npm packages used in foreign imports, leaving the JS dependency tree vulnerable to drift. Uncertainty: teams can either rely solely on Spago's lockfile and manage J