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semantic/prototype/DoubtTests/RangedDiff.swift
2015-10-22 16:02:03 -04:00

30 lines
888 B
Swift

struct RangedDiff {
typealias Diff = Free<String, (RangedTerm.Term.Annotation, RangedTerm.Term.Annotation), Patch<RangedTerm.Term>>
let a: RangedTerm
let b: RangedTerm
let diff: Diff
}
extension RangedDiff: Arbitrary {
static let interpreter = Interpreter<RangedTerm.Term>(equal: ==, comparable: const(true), cost: Diff.sum(Patch.difference))
static var arbitrary: Gen<RangedDiff> {
return RangedTerm.arbitrary.bind { a in
RangedTerm.arbitrary.fmap { b in
RangedDiff(a: a, b: b, diff: interpreter.run(a.term, b.term))
}
}
}
static func shrink(diff: RangedDiff) -> [RangedDiff] {
return RangedTerm.shrink(diff.a).map { RangedDiff(a: $0, b: diff.b, diff: interpreter.run($0.term, diff.b.term)) }
+ RangedTerm.shrink(diff.b).map { RangedDiff(a: diff.a, b: $0, diff: interpreter.run(diff.a.term, $0.term)) }
}
}
import Doubt
import Prelude
import SwiftCheck