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type Transaction<'a> = string -> 'a | |
module Transaction = | |
let map<'a,'b> (mapper:'a -> 'b) (t:Transaction<'a>) : Transaction<'b> = | |
(fun x -> mapper (t x)) | |
let bind<'a,'b> (binder:'a -> Transaction<'b>) (t:Transaction<'a>) : Transaction<'b> = | |
(fun x -> binder (t x) x) | |
let execute connectionString (t:Transaction<'a>) = | |
t ConnectionString | |
type SqlReader<'state, 'element> = | |
abstract member Read : reader:('state -> System.Data.IDataReader -> 'element -> 'state*bool) -> 'state -> Transaction<'state> | |
module SqlReader = | |
let read<'state,'element> reader state (x:SqlReader<'state, 'element>) = x.Read reader state | |
let fold<'state, 'element> folder = read<'state, 'element> (fun s _r x -> (folder s x), true) | |
let readList<'a> = fold<_ list, 'a> (fun s x -> x::s) [] >> Transaction.map List.rev | |
let optional<'a> = read<_ option, 'a> (fun s _r x -> (Some x), false) None | |
let single<'a> = optional<'a> >> Transaction.map (Option.defaultWith (fun () -> failwithf "Expected one row, got zero")) | |
let genericList<'a> = new System.Collections.Generic.List<'a>() |> fold<_, 'a> (fun s x -> s.Add(x); s) | |
let a : int = | |
SqlReaderProvider<"SELECT @n AS N">.Query(5) | |
|> SqlReader.single | |
|> Transaction.execute | |
() |
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