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Haskell コードの次のブロックの翻訳を手伝ってください。run関数は、パターンとして抽象化された特定の正規表現に対応するテキスト文字列を生成します。以下の F# コードのブロックで確認できる型 Pattern の宣言。次のような実行機能をテストできます

genex $ POr [PConcat [PEscape( DoPa 1) 'd'], PConcat [PEscape (DoPa 2) 'd']]

{-# LANGUAGE RecordWildCards, NamedFieldPuns #-}
import qualified Data.Text as T
import qualified Control.Monad.Stream as Stream
import Text.Regex.TDFA.Pattern
import Control.Monad.State
import Control.Applicative

genex = Stream.toList . run

maxRepeat :: Int
maxRepeat = 3

each = foldl1 (<|>) . map return

run :: Pattern -> Stream.Stream T.Text
run p = case p of
    PBound low high p -> do
        n <- each [low..maybe (low+maxRepeat) id high]
        fmap T.concat . sequence $ replicate n (run p) 
    PConcat ps -> fmap T.concat . Stream.suspended . sequence $ map run ps
    POr xs -> foldl1 mplus $ map run xs
    PEscape {..} -> case getPatternChar of
        'd' -> chars $ ['0'..'9']
        'w' -> chars $ ['0'..'9'] ++ '_' : ['a'..'z'] ++ ['A'..'Z']
        ch  -> isChar ch
    _      -> error $ show p
    where
    isChar = return . T.singleton
    chars = each . map T.singleton

以下に、私の貧弱な試みを示します。動作しますが、正しくありません。問題は以下にあります。パースがそのようなパターンを生成すると仮定しましょう

"\\d\\d" を解析します;; val it : Pattern = POr [PConcat [PEscape (DoPa 1,'d'); PEscape (DoPa 2,'d')]]

と

"\\d{2}" を解析します;; val it : Pattern = POr [PConcat [PBound (2,Some 2,PEscape (DoPa 1,'d'))]]

したがって、両方のパターンを実行して、 seq [['2';を受け取ることを期待しています。'2']; ['2'; '3']; ['2'; '1']; ['2'; '4']; ...] seq ["22";に対応するもの。"23"; "21"; "24"; ...] (文字列ごとに 2 つの記号)

これは最初のケースで有効です。

POr [PConcat [PEscape (DoPa 1,'d'); PEscape (DoPa 2,'d')]] |> 実行;; val it : seq = seq [['2'; '2']; ['2'; '3']; ['2'; '1']; ['2'; '4']; ...]

seq ["22"; "23"; "21"; "24"; ...]

しかし、2番目ではありません

POr [PConcat [PBound (2,Some 2,PEscape (DoPa 1,'d'))]] |> run;; val it : seq = seq [['2']; ['2']; ['2']; ['3']; ...]

seq ["2"; "2"、"2"; "3"、"2"; "1"、"2"; "4";...] (文字列ごとに 1 つの記号)

次の句を使用して、さまざまなバリアントをテストしました。

| POr ps                -> Seq.concat (List.map run ps)
| PConcat ps            -> (sequence (List.map (run >> Seq.concat) ps))
| PBound (low,high,p)   ->

しかし、すべて無駄です。正しい訳がわかりません。

-文字リストの代わりに文字列または配列を使用する必要があるかもしれません。

-そして、Seq は Control.Monad.Stream と非常によく似ていると思います。そうですか？

助けてくれてありがとう

open System

/// Used to track elements of the pattern that accept characters or are anchors
type DoPa = DoPa of int

/// Pattern is the type returned by the regular expression parser.
/// This is consumed by the CorePattern module and the tender leaves
/// are nibbled by the TNFA module.
type Pattern = PEmpty
             | POr     of Pattern list                  // flattened by starTrans
             | PConcat of Pattern list                  // flattened by starTrans
             | PBound  of int * (int option) * Pattern  // eliminated by starTrans
             | PEscape of DoPa * char                   // Backslashed Character

let maxRepeat = 3

let maybe deflt f opt = 
    match opt with
    | None -> deflt
    | Some v -> f v

/// Cartesian production
/// try in F# interactive: sequence [[1;2];[3;4]];;
let rec sequence = function 
  | []      -> Seq.singleton [] 
  | (l::ls) -> seq { for x in l do for xs in sequence ls do yield (x::xs) } 



let from'space'to'tilda     =  [' '..'~'] |> List.ofSeq
let numbers                 =  ['0'..'9'] |> List.ofSeq
let numbers'and'alphas      =  (['0'..'9'] @ '_' :: ['a'..'z'] @ ['A'..'Z']) |> List.ofSeq
let whites                  =  ['\009'; '\010'; '\012'; '\013'; '\032' ] |> List.ofSeq

let rec run (p:Pattern) : seq<char list> =
    let chars chs = seq { yield [for s in chs -> s] }
    match p with
    | POr ps                -> Seq.concat (List.map run ps)
    | PConcat ps            -> (sequence (List.map (run >> Seq.concat) ps))
    | PBound (low,high,p)   -> 
        let ns = seq {low .. maybe (low + maxRepeat) id high}
        Seq.concat (seq { for n in ns do yield  sequence (List.replicate n (((run >> Seq.concat)  p))) })
        // Seq.concat (seq { for n in ns do yield     ((List.replicate n (run p)) |> Seq.concat |> List.ofSeq |> sequence)})
        //((List.replicate low (run p)) |> Seq.concat |> List.ofSeq |> sequence)
        // PConcat [ for n in ns -> p] |> run
    | PEscape(_, ch)  -> 
        match ch with
        | 'd' -> chars numbers
        | 'w' -> chars numbers'and'alphas
        | ch  -> chars [ch]
    | _                     -> Seq.empty
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1 に答える 1

4

Data.TextHaskell からF# に変換しなかった理由がわかりませんstring。2 つの関数を模倣する必要があるだけです。それとは別に、機能させるためにいくつかの変更を加えました。このようにして、元のコードと簡単に比較できます。(* *) 間の置き換えられたコードを参照してください。

open System

// Mimic Data.Text as T
module T =
    let concat (x:seq<_>) = System.String.Concat x
    let singleton (x:char) = string x


/// Used to track elements of the pattern that accept characters or are anchors
type DoPa = DoPa of int

/// Pattern is the type returned by the regular expression parser.
/// This is consumed by the CorePattern module and the tender leaves
/// are nibbled by the TNFA module.
type Pattern = PEmpty
             | POr     of Pattern list                  // flattened by starTrans
             | PConcat of Pattern list                  // flattened by starTrans
             | PBound  of int * (int option) * Pattern  // eliminated by starTrans
             | PEscape of DoPa * char                   // Backslashed Character

let maxRepeat = 3

let maybe deflt f opt = 
    match opt with
    | None -> deflt
    | Some v -> f v

/// Cartesian production
/// try in F# interactive: sequence [[1;2];[3;4]];;
let rec sequence = function 
  | []      -> Seq.singleton [] 
  | (l::ls) -> seq { for x in l do for xs in sequence ls do yield (x::xs) } 



let from'space'to'tilda     =  [' '..'~'] |> List.ofSeq
let numbers                 =  ['0'..'9'] |> List.ofSeq
let numbers'and'alphas      =  (['0'..'9'] @ '_' :: ['a'..'z'] @ ['A'..'Z']) |> List.ofSeq
let whites                  =  ['\009'; '\010'; '\012'; '\013'; '\032' ] |> List.ofSeq

let rec run (p:Pattern) (*: seq<char list> *) =
    (* let chars chs = seq { yield [for s in chs -> s] } *)
    let chars (chs:seq<char>)  = Seq.map string chs

    match p with
    | POr ps                -> Seq.concat (List.map run ps)
    | PConcat ps            -> Seq.map T.concat << sequence <| List.map run ps (* (sequence (List.map (run >> Seq.concat) ps)) *) 
    | PBound (low,high,p)   -> 
        seq {
        for n in [low..maybe (low+maxRepeat) id high] do
            yield! (  (Seq.map T.concat << sequence) (List.replicate n (run p)) )}
        (*let ns = seq {low .. maybe (low + maxRepeat) id high}
        Seq.concat (seq { for n in ns do yield  sequence (List.replicate n (((run >> Seq.concat)  p)))  *)

        // Seq.concat (seq { for n in ns do yield     ((List.replicate n (run p)) |> Seq.concat |> List.ofSeq |> sequence)})
        //((List.replicate low (run p)) |> Seq.concat |> List.ofSeq |> sequence)
        // PConcat [ for n in ns -> p] |> run
    | PEscape(_, ch)  -> 
        match ch with
        | 'd' -> chars numbers
        | 'w' -> chars numbers'and'alphas
        | ch  -> chars [ch]
    | _                     -> Seq.empty


アップデート

Haskell コードを F# に変換する場合は、型クラスを使用するものを含む多くの Haskell 関数を模倣するこのコードを使用してみてください。元の Haskell コードにできるだけ近い翻訳をテストしましたが、F# List (怠惰ではありません) を使用すると、次のようになります。

#load "Prelude.fs"
#load "Monad.fs"
#load "Applicative.fs"
#load "Monoid.fs"

open Prelude
open Control.Monad.Base
open Control.Applicative

module T =
    let concat (x:list<_>) = System.String.Concat x
    let singleton (x:char) = string x

type DoPa = DoPa of int

type Pattern = PEmpty
             | POr     of Pattern list
             | PConcat of Pattern list
             | PBound  of int * (int option) * Pattern
             | PEscape of DoPa * char

let maxRepeat = 3

let inline each   x = foldl1 (<|>) << map return'  <| x

let rec run p:list<_> = 
    let inline isChar x = return' << T.singleton   <| x
    let inline chars  x = each << map T.singleton  <| x
    match p with
    | PBound (low,high,p) -> do' {
        let! n = each [low..maybe (low+maxRepeat) id high]
        return! (fmap T.concat << sequence <| replicate n (run p))}
    | PConcat ps -> fmap T.concat << sequence <| map run ps
    | POr xs -> foldl1 mplus <| map run xs
    | PEscape (_, ch) -> 
        match ch with
        | 'd' -> chars <| ['0'..'9']
        | 'w' -> chars <| ['0'..'9'] @ '_' :: ['a'..'z'] @ ['A'..'Z']
        | ch  -> isChar ch
    | _  -> failwith <| string p

let genex = run
于 2012-07-05T22:50:09.603 に答える