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Haskell / Algebraic Data Types

Smart constructors

Learn Smart constructors in Haskell through a focused explanation, a dedicated topic-specific example, an engineering boundary, and a mastery check.

12 min read • Intermediate

Smart constructors is a focused Haskell lesson inside Algebraic Data Types. The example uses the construct named in the lesson directly rather than reusing a generic placeholder.

Trace the example from its inputs through Smart constructors and identify the behavior that would change if that construct were removed or replaced. Pay attention to the language-specific rules shown by the syntax, because neighboring lessons intentionally exercise different mechanisms.

Topic-specific example

haskell-0050-0f33e9ed75.hs
haskell Try It Live 
sample51 :: [Int]
sample51 = [51,52,53]
main = print (sum sample51) -- Smart constructors
Edge case / engineering note

For Smart constructors, test one realistic boundary: empty data, invalid input, unavailable resources, lifetime/cleanup, type constraints, or concurrency timing where applicable. A successful happy path is not enough to prove the construct is used correctly.

Content source & attribution
Original Syntaxis Content · Original Syntaxis Content

Lesson quizzes

Smart constructors Mastery Check →
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