**Packages**- containers
- base

Evaluates its first argument to head normal form, and then returns its second argument as the result.

Evaluate each action in the sequence from left to right, and collect the results.

Evaluate each action in the sequence from left to right, and ignore the results.

Evaluate each monadic action in the structure from left to right, and ignore the results.

Evaluate each action in the structure from left to right, and ignore the results.

The subsequences function returns the list of all subsequences of the argument.
> subsequences "abc" == ["","a","b","ab","c","ac","bc","abc"]