Module helpers 

Various selector functions for different use cases.

A selector function accepts an iterator over (Rule, Update) pairs and returns the selected Update, or None.

morph will call the given selector function when there is an ambiguity in which rule to apply. That is, when more than one rule from the same group returns [Some(...)] for a given sub-tree.

Functions

select_first

Returns the first available Update if there is one, otherwise returns None.

select_panic

Panics when called by the engine, printing the original subtree and all applicable rules and their results.

select_random

Selects a random Update from the iterator.

select_smallest_subtree

Selects the Update which results in the smallest subtree.

select_user_input

Selects an Update based on user input through stdin.

Type Aliases

SelectorFn

A uniform type for selector functions such as select_first.