open System.Collections.Generic

open System.Data

let map f (dt:DataTable) =

[

for row in dt.Rows do

yield row |> f

]

let iter f (dt:DataTable) =

for row in dt.Rows do

f row.ItemArray

let toList(dt:DataTable) = map id dt

let groupBy f (dt:DataTable) =

map f dt

|> Seq.groupBy (fst)

|> Seq.map (fun (k, v) -> k, Seq.map snd v)

let cache (cache:IDictionary<string,'a>) f (dt:DataTable) =

for row in dt.Rows do

match f row with

| Some(key,item) -> cache.Add(key,item)

| None -> ()

cache.Values |> Seq.toList

let mapChoose (f:DataRow -> 'a option) (dt:DataTable) =

if isNull dt then []

else

[

for row in dt.Rows do

match f row with

| Some(a) -> yield a

| None -> ()

]

let choose (f : DataRow -> DataRow option) (dt:DataTable) =

let copy = dt.Clone()

copy.Rows.Clear()

for row in dt.Rows do

match row |> f with

| Some(a) -> copy.Rows.Add(a.ItemArray) |> ignore

| None -> ()

copy

let filter f (dt:DataTable) =

choose (fun r ->

if f r

then Some r

else None

) dt

let headers (dt:System.Data.DataTable) =

[

for col in dt.Columns do

yield col.ColumnName

]

let printDataTable (dt:System.Data.DataTable) =

if isNull dt then ()

else

let widths = Dictionary<int, int>()

let computeMaxWidth indx length =

let len =

match widths.TryGetValue(indx) with

| true, len -> max len length

| false, _ -> length

widths.[indx] <- len

let i = ref 0

for col in dt.Columns do

computeMaxWidth !i col.ColumnName.Length

incr i

let rows =

dt

|> map (fun r -> r.ItemArray)

|> List.fold (fun rows row ->

let values = row |> Array.map (fun x -> x.ToString().Trim()) |> List.ofArray

values |> List.iteri (fun i x -> computeMaxWidth i x.Length)

values :: rows

) []

i := 0

for col in dt.Columns do

printf "%*s " (widths.[!i] + 2) col.ColumnName

incr i

printfn ""

for row in rows |> List.rev do

for (index,value) in row |> List.mapi (fun i x -> i,x) do

printf "%*s " (widths.[index] + 2) value

printfn ""