schematic-0.5.0.0: src/Data/Schematic/Verifier/Number.hs

module Data.Schematic.Verifier.Number where

import {-# SOURCE #-} Data.Schematic.Schema
import Data.Schematic.Verifier.Common

toStrictNumber :: [DemotedNumberConstraint] -> [DemotedNumberConstraint]
toStrictNumber = map f
  where
    f (DNLe x) = DNLt (x + 1)
    f (DNGe x) = DNGt (x - 1)
    f x        = x

data VerifiedNumberConstraint
  = VNEq Integer
  | VNBounds (Maybe Integer) (Maybe Integer)
  deriving (Show)

verifyNumberConstraints
  :: [DemotedNumberConstraint]
  -> Maybe VerifiedNumberConstraint
verifyNumberConstraints cs' = do
  let
    cs = toStrictNumber cs'
    mlt = simplifyDNLs [x | DNLt x <- cs]
    mgt = simplifyDNGs [x | DNGt x <- cs]
  meq <- verifyDNEq [x | DNEq x <- cs]
  verifyEquations mgt meq mlt
  Just $
    case meq of
      Just eq -> VNEq eq
      Nothing -> VNBounds mgt mlt