fthomas/refined 0.0.1

on GitHub

First public release of refined.

Overview

This is a port of the refined Haskell library to Scala.
The linked websites provides an excellent motivation why this kind of library
is useful.

This library consists of:

• Type-level predicates for refining other types, like UpperCase, Positive,
  Greater[_0] And LessEqual[_2], or Length[Greater[_5]]. There are also higher
  order predicates for combining proper predicates like And[_, _], Or[_, _],
  Not[_], Forall[_], or Size[_].
• A Predicate type class that is able to validate a concrete data type (like Double)
  against a type-level predicate (like Positive).
• Two functions refine and refineLit that take a predicate P and some value
  of type T, validates this value with a Predicate[P, T] and returns the value
  with type T @@ P if validation was successful or an error otherwise.
  (@@ is shapeless' type for tagging types :-))

Provided predicates

The library comes with these predefined predicates:

boolean

• True: constant predicate that is always true
• False: constant predicate that is always false
• Not[P]: negation of the predicate P
• And[A, B]: conjunction of the predicates A and B
• Or[A, B]: disjunction of the predicates A and B

char

• LowerCase: checks if a Char is a lower case character
• UpperCase: checks if a Char is an upper case character

collection

• Empty: checks if a TraversableOnce is empty
• NonEmpty: checks if a TraversableOnce is not empty
• Forall[P]: checks if the predicate P holds for all elements of a
  TraversableOnce
• Exists[P]: checks if the predicate P holds for some elements of a
  TraversableOnce
• Size[P]: checks if the size of a TraversableOnce satisfies the predicate P

numeric

• Less[N]: checks if a numeric value is less than N
• LessEqual[N]: checks if a numeric value is less than or equal to N
• Greater[N]: checks if a numeric value is greater than N
• GreaterEqual[N]: checks if a numeric value is greater than or equal to N
• Equal[N]: checks if an integral value is equal to N
• Positive: checks if a numeric value is greater than zero
• Negative: checks if a numeric value is less than zero
• ZeroToOne: checks if a numeric value is in the interval [0, 1]

Released on 2015-05-15