Union interface
A union interface is a Go generic constraint whose type set permits multiple alternative types or underlying types.
Learn Go with Pocket-Sized Projects
A union interface is a Go generic constraint whose type set combines multiple permitted types or underlying types.
- How it is used
- Restricts generic functions to selected integer types while permitting shared operations such as addition.
- How deep it goes
- Defines exact and underlying-type unions, then applies them to generic constraints without developing a broader constraint design.
- Examples
- Uses int, int32, int64, a named age type, and summable constraints with and without tilde syntax.
- What you can do after
- Apply it via Go generics to accept a deliberate set of numeric types and use their common operators.
Read how Learn Go with Pocket-Sized Projects explains union interface →
100 Go Mistakes and How to Avoid Them
The union operator | combines type terms in a Go generic constraint to permit multiple alternative types.
- How it is used
- Restricts generic type arguments to a defined set of alternative types.
- How deep it goes
- Defines union syntax through getKeys and contrasts exact types with underlying-type approximations using ~.
- Examples
- Uses customConstraint, ~int | ~string, and the generic getKeys map helper.
- What you can do after
- Apply it via Go generic constraints to admit selected alternative key types in reusable functions.
Read how 100 Go Mistakes and How to Avoid Them explains union interface →
Related concepts
- type constraintkind of · A type constraint is a rule that restricts admissible types or type arguments by requiring specified relationships, structures, properties, or supported operations.
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