Implicit argument
An implicit argument is a function input supplied through invocation context, naming convention, or language mechanisms rather than explicitly at the call site.
Grokking Simplicity
A code smell in which a function's name encodes a value that would more appropriately be supplied explicitly as an argument.
- How it is used
- Detects duplication when function names encode varying fields or operations instead of exposing them as values.
- How deep it goes
- Explains recognition, four refactoring steps, validation, nested updates, and callbacks, but stops short of a full language-internals treatment.
- Examples
- Uses shopping-cart field setters, quantity and size incrementers, multiplication functions, and nested shirt options.
- What you can do after
- Diagnose/debug with it by spotting name-encoded differences and refactoring them into explicit, validated arguments.
Akka in Action, Second Edition
An implicit argument is a Scala method argument that the compiler can automatically supply from a compatible implicit value.
- How it is used
- Supplies Akka ask-operation parameters automatically, reducing repeated timeout arguments in asynchronous manager-worker workflows.
- How deep it goes
- Defines compiler lookup and demonstrates timeout insertion, but defers Scala’s broader implicit-scope rules.
- Examples
- Uses a manager parsing text through workers, with a three-second timeout and success-or-failure reports.
- What you can do after
- Apply it via Akka’s ask API by declaring a compatible implicit timeout and omitting that parameter from calls.
Read how Akka in Action, Second Edition explains implicit argument →
Related concepts
- code smellkind of · A code smell is a recognizable symptom in source code suggesting a potential design, implementation, or maintainability problem without necessarily indicating a defect.
- extract function argument refactoringaddressed by · A refactoring technique that moves varying behavior into a function argument so the surrounding function becomes reusable.
- explicit inputcontrasts with · An explicit input is a value supplied directly by a caller through an argument at a function's invocation site.
- compilerused by · A compiler is software that translates source code into executable code or another representation, while analyzing it according to the source language’s rules.
- identifierpart of · An identifier is a name or value that denotes or distinguishes an entity or program element within a system.
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