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Languages & runtimes · #haskell
Thunk accumulation in lazy evaluation Haskell's default lazy evaluation defers computations by creating thunks. When using a recursive accumulation pattern, such as with foldl , these unevaluated expressions can build up in memory, leading to a space leak before the final result is demanded. Strictness and WHNF While foldl' and the BangPatterns extension are
A Haskell service using the persistent library needs to page through a table that can grow to millions of rows. The straightforward approach — selectList with LimitTo and OffsetBy , which maps to SQL LIMIT / OFFSET — has two drawbacks at scale: the database still reads and discards every row preceding the offset, and rows inserted or deleted between requests
The goal is to ensure that System.Timeout.timeout can cancel an action even when the action masks asynchronous exceptions. The current implementation relies on throwing ThreadKilled via throwTo to the worker thread; if the action uses mask or uninterruptibleMask , the exception is delayed until masking ends, allowing the action to exceed the time limit. An o
Context Safe Haskell enforces least-privilege compilation through Safe , Trustworthy , and Unsafe module classifications, restricting primitives like unsafePerformIO at compile time. Trust is granted statically when a module is marked Trustworthy and accepted by the compiler. Problem There is no standard mechanism to revoke or expire that trust after compila
The goal is to decide whether to allow Nix to automatically populate the GHC package database from the Nix store or to override it with a custom database location for incremental Haskell builds. Nix creates pure build environments that isolate GHC and its dependencies, placing the package database in the Nix store rather than the usual Cabal or Stack user da