sigma-andex / idris-refined

Port of Scala/Haskell Refined library to Idris

Idris-refined

Port of scala refined library to idris using dependent pairs.

Installation

git clone [e-mail]:janschultecom/idris-refined.git
make install
idris -p Refined
Idris> :module Refined

Example

Types can be refined using Refined:

-- Only digits
zeroIsDigit : Refined Char Digit
zeroIsDigit = '0'
-- zeroIsDigit = 'a' will result in compile-time error

-- Only letters
upperAIsLetter : Refined Char Letter
upperAIsLetter = 'A'
-- upperAIsLetter = '0' will result in compile-time error

-- Letters or Digits
lowerAIsAlpha : Refined Char AlphaNumeric
lowerAIsAlpha = 'a'

upperAIsAlpha : Refined Char AlphaNumeric
upperAIsAlpha = 'A'

zeroIsAlpha : Refined Char AlphaNumeric
zeroIsAlpha = '0'
-- z = '$' will result in compile-time error

Refined types can be passed to functions expecting ordinary types.

test : Char -> IO ()
test c = print $ show c

main : IO ()
main = test Refined.x

See the Test case for more examples.

Predicates

Nat

• Greater n: checks if a Nat is strictly greater than n
• GreaterEqual n: checks if a Nat is greater or equal to n
• Less n: checks if a Nat is strictly less than n
• LessEqual n: checks if a Nat is less or equal to n

Char

• Digit: checks if a Char is a digit
• Letter: checks if a Char is a letter
• AlphaNumeric: checks if a Char is a letter or digit
• LowerCase: checks if a Char is a lower case character
• UpperCase: checks if a Char is an upper case character
• Whitespace: checks if a Char is white space

String

• NonEmpty : checks if a String has at least one character