Do notation
Do notation is Haskell syntax for sequencing monadic computations and binding their intermediate results in a readable, imperative-like form.
Learn Haskell by Example
Do notation, or a do block, is Haskell syntax for sequencing monadic computations and binding their intermediate results.
- How it is used
- Sequences IO and parser actions while passing produced values to later computations.
- How deep it goes
- Defines IO-block behavior first, then relates the syntax to monadic bind and Parser implementation.
- Examples
- Uses an echo program, a recursive numbered-input loop, monadic addition, and PNM-header parsers.
- What you can do after
- Apply it via Haskell IO and Parser actions to sequence work, bind results, and handle action-valued branches.
Functional Design and Architecture: Examples in Haskell
Do notation is Haskell syntax for expressing a sequence of monadic computations with implicit binding between steps.
- How it is used
- Simplifies sequences of monadic computations and separates functional scenarios from their eventual interpretation.
- How deep it goes
- Explains binding through Maybe and Free Monad examples, but defers the broader mechanics of monadic abstractions.
- Examples
- Uses user lookup with Maybe and a terminal script that reads and echoes two lines.
- What you can do after
- Apply it via Haskell do-notation to shorten monadic workflows and construct interpretable functional scenarios.
Read how Functional Design and Architecture: Examples in Haskell explains do notation →
Related concepts
- bindequivalent to · Bind is a monadic operation that sequences a context-bearing computation with a function producing the next computation while flattening the resulting nested context.
- IOconfigures · IO is an abstraction representing input/output or other side-effecting computations and operations, often as composable values whose execution is separately controlled.
- syntactic sugarkind of · Syntactic sugar is language syntax that provides a more convenient or readable form for expressing behavior already representable by other constructs without changing its meaning.
- monaduses · A monad is a functional abstraction that encapsulates computational context and provides operations for composing computations while preserving that context.
- let keywordcontrasts with · A let construct is a language feature that introduces a name binding associating an identifier with a value or expression.
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