Module branch

Chaining branch combinators.

This module provides functions for chaining branching Handler combinators like try_and and or. These chaining combinators are often more ergonomic when combining more than two handlers and can also improve syntax and readability by more naturally grouping together branches in complex expressions.

Chaining is either static or dynamic. Static chaining refers to chaining a fixed number of handlers of any types. Dynamic chaining refers to chaining an unknown number of handlers of the same type. The boxed function can be used to allow different handler types with dynamic chaining via type erasure.

Functions in this module accept tuples of handlers for static chaining and Vecs of handlers for dynamic chaining. Handlers are always executed in order.

Structs

• DynamicAnd
• DynamicOr
• DynamicTryAnd
• DynamicTryOr

Traits

• AndChain
  Types that describe a sequence of event handlers that can be combined via and.
• OrChain
  Types that describe a sequence of event handlers that can be combined via or.
• TryAndChain
  Types that describe a sequence of event handlers that can be combined via try_and.
• TryOrChain
  Types that describe a sequence of event handlers that can be combined via try_or.

Functions

• and
  Executes the handlers in a tuple or Vec in order until a handler does not match the event. If all handlers match, then the output of the last handler in the sequence is returned, otherwise Handled::Unmatched.
• or
  Executes the handlers in a tuple or Vec in order until a handler matches the event. If any handler matches, then the output of that handler is returned, otherwise Handled::Unmatched.
• try_and
  Executes the handlers in a tuple or Vec in order until a handler does not match the event or returns an error. If a handler matches but returns an error, the error is returned. If all handlers match and no handlers return an error, then the output of the last handler in the sequence is returned, otherwise Handled::Unmatched.
• try_or
  Executes the handlers in a tuple or Vec in order until a handler matches the event and does not return an error. If any handler matches and returns a non-error, then the output of that handler is returned, otherwise Handled::Unmatched.