Documentation
¶
Overview ¶
Package chain. chain provides fluent method chaining for Result and Option types. This enables a more readable, pipeline-style programming pattern similar to Rust's method chaining.
Benefits:
- Fluent API: Chain multiple operations in a readable sequence
- Type safety: Compiler tracks type transformations through the chain
- No nesting: Avoids deep nesting of Map/AndThen calls
- Better readability: Operations read left-to-right like a pipeline
Example - Traditional vs Chained:
// Traditional nested style
result := result.AndThen(
result.Map(
findUser(123),
func(u User) string { return u.Name },
),
func(name string) Result[Profile] { return findProfile(name) },
)
// Fluent chained style
result := chain.Chain(findUser(123)).
Map(func(u User) string { return u.Name }).
AndThen(findProfile).
Unwrap()
Package chain. chain2 provides fluent method chaining for Result and Option types. This enables a more readable, pipeline-style programming pattern similar to Rust's method chaining.
Benefits:
- Fluent API: Chain multiple operations in a readable sequence
- Type safety: Compiler tracks type transformations through the chain
- No nesting: Avoids deep nesting of Map/AndThen calls
- Better readability: Operations read left-to-right like a pipeline
Index ¶
- type ApplyToResult
- func (applyToResult *ApplyToResult[Out, In]) AndThen(fn func(In) result.Result[Out]) result.Result[Out]
- func (applyToResult *ApplyToResult[Out, In]) Map(fn func(In) Out) result.Result[Out]
- func (applyToResult *ApplyToResult[Out, In]) MapError(fn func(error) error) *ApplyToResult[Out, In]
- func (applyToResult *ApplyToResult[Out, In]) OrElse(fallback Out) Out
- func (applyToResult *ApplyToResult[Out, In]) OrElseGet(fn func(error) Out) Out
- func (applyToResult *ApplyToResult[Out, In]) Unwrap() result.Result[Out]
- type ApplyToResult2
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type ApplyToResult ¶
type ApplyToResult[Out, In any] struct { // contains filtered or unexported fields }
ApplyToResult [Out, In] is the first step in a Result chaining pipeline. It holds a Result[In] and provides methods that transform it to Result[Out].
func Chain ¶
func Chain[Out, T any](r result.Result[T]) *ApplyToResult[Out, T]
Chain starts a new chaining pipeline with a Result[In]. Use this as the entry point for fluent Result operations.
Example:
userResult := findUser(123)
chain.Chain(userResult).
Map(func(u User) string { return u.Name }).
AndThen(validateName).
Unwrap()
func (*ApplyToResult[Out, In]) AndThen ¶
func (applyToResult *ApplyToResult[Out, In]) AndThen(fn func(In) result.Result[Out]) result.Result[Out]
AndThen chains a Result-returning function. Similar to Map but for functions that can fail.
Example:
chain.Chain(validateEmail("test@example.com")).
AndThen(func(email string) result.Result[User] {
return createUser(email)
}).
Unwrap()
func (*ApplyToResult[Out, In]) Map ¶
func (applyToResult *ApplyToResult[Out, In]) Map(fn func(In) Out) result.Result[Out]
Map transforms the value inside the Result using fn. Returns a new ApplyToResult that can continue the chain.
Example:
chain.Chain(Ok(42)).
Map(func(x int) string { return fmt.Sprintf("value: %d", x) }).
Unwrap() // Result[string] with "value: 42"
func (*ApplyToResult[Out, In]) MapError ¶
func (applyToResult *ApplyToResult[Out, In]) MapError(fn func(error) error) *ApplyToResult[Out, In]
MapError transforms the error if the Result is in error state.
Example:
chain.Chain(dbQueryResult).
MapError(func(err error) error {
return fmt.Errorf("database error: %w", err)
}).
Unwrap()
func (*ApplyToResult[Out, In]) OrElse ¶
func (applyToResult *ApplyToResult[Out, In]) OrElse(fallback Out) Out
OrElse terminates the chain and returns the value or fallback.
func (*ApplyToResult[Out, In]) OrElseGet ¶
func (applyToResult *ApplyToResult[Out, In]) OrElseGet(fn func(error) Out) Out
OrElseGet terminates the chain and returns the value or computed fallback.
func (*ApplyToResult[Out, In]) Unwrap ¶
func (applyToResult *ApplyToResult[Out, In]) Unwrap() result.Result[Out]
Unwrap terminates the chain and returns the final Result. This is usually the last call in a chain.
type ApplyToResult2 ¶
type ApplyToResult2[Out1, Out2, In any] struct { // contains filtered or unexported fields }
ApplyToResult2 [Out1, Out2, In] represents a 2-step transformation pipeline.
func Chain2 ¶
func Chain2[Out2, Out1, T any](result result.Result[T]) *ApplyToResult2[Out1, Out2, T]
Chain2 starts a chain that expects exactly 2 transformations. Useful when you know the exact number of steps for type clarity.
func (ApplyToResult2[Out1, Out2, T]) AndThen ¶
func (applyToResult2 ApplyToResult2[Out1, Out2, T]) AndThen(fn func(T) result.Result[Out1]) *ApplyToResult[Out2, Out1]
func (ApplyToResult2[Out1, Out2, T]) Map ¶
func (applyToResult2 ApplyToResult2[Out1, Out2, T]) Map(fn func(T) Out1) *ApplyToResult[Out2, Out1]
Source Files