仕事で使うF#

F#

bleis-tift

August 28, 2011

F#
F#
NParsec FParsec

1 3
[1; 2; 3]
[1..3]
1::2::3::[]
1::2::[3]
[ 1
2
3 ]

let xs = [2..10]
let ys = 1::xs

1
let x, y = 10, 20
printfn "%A" (x, y) // => (10, 20)

2
let (x, y) as tpl = 1, 2
printfn "%A" tpl // => (1, 2)
printfn "%A" (x, y) // => (1, 2)
printfn "(%d, %d)" x y // => (1, 2)

let [x; y] as lst = [1; 2]
printfn "%A" lst // => [1; 2]
printfn "%A" [x; y] // => [1; 2]
printfn "[%d; %d]" x y // => [1; 2]

warning FS0025:
’[_;_;_]’

2

(2, "hoge") // int * string

//
[2; "hoge"]

[box 1; box "hoge"] // obj list

// ,
let p = " ", 21

type Person = {
Name: string
Age: int
}
let p = { Name = " "; Age = 21 }

4

F#

type Person(name: string, age: int) =
member this.Name = name
member this.Age = age
let p = Person(" ", 21)

type Person = { Name: string; Age: int }
let p = { Name = " "; Age = 21 }

type Person(name: string, age: int) =
member x.Name = name
member x.Age = age
let f p = p.Name

error FS0072:

type Person = { Name: string; Age: int }
let f p = p.Name

type Person =
{Name: string;
Age: int;}
val f : Person -> string

C#

public abstract class HtmlElem {}
public class Heading : HtmlElem {
public int Level { get; private set; }
public string Text { get; private set; }
public Heading(int level, string txt) {
Level = level; Text = txt; } }
public class Text : HtmlElem {
public string Text { get; private set; }
public Text(string txt) {
Text = txt; } }
public class HorizontalLine : HtmlElem {}

F#

type HtmlElem =
| Text of string
| Heading of int * string
| HorizontalLine

Equals

GetHashCode
Make static analyzers happy
== !=

ToString

let add = function
| 0, y -> y
| x, 0 -> x
| x, y -> x + y
function

match function

match
let add tpl =
match tpl with
| x, y -> x + y

function
let add = function
| x, y -> x + y

type t = { Tag: int; Value: int }
let value { Value = v } = v

match

match
let add tpl =
match tpl with
| x, y -> x + y

function
let add = function
| x, y -> x + y

let add (x, y) = x + y

Person
type Name = {
FirstName: string
LastName: string
}
type Person = { Name: Name; Age: int }

let f x =
let { Name = { FirstName = fn } } = x
fn

Maybe
type MaybeBuilder() =
member this.Bind(x, f) =
x |> Option.bind f
member this.Return(x) = Some x
let maybe = MaybeBuilder()

let plus db = maybe {
let! x = db |> Map.tryFind "x"
let! y = db |> Map.tryFind "y"
return x + y
}

Map-Reduce ( )

fold reduce
fold

fold reduce

fold reduce

F#

fold reduce
> List.fold;;
val it : ((’a -> ’b -> ’a) -> ’a -> ’b list -> ’a)
= <fun:clo@1>
> List.reduce;;
val it : ((’a -> ’a -> ’a) -> ’a list -> ’a)
= <fun:clo@2-1>

fold

reduce list
list

fold

fold
sum
forall
map
ﬁlter

fold sum

sum
let sum xs =
List.fold (+) 0 xs

fold forall

forall
let forall p xs =
xs
|> List.fold (fun acc x -> acc && (p x)) true

exists

fold map

map
let map f xs =
([], xs)
||> List.fold (fun acc x ->
acc @ [f x]
)

fold ﬁlter

ﬁlter
let filter p xs =
([], xs)
||> List.fold begin acc x ->
if p x then acc @ [x]
else acc
end

fold

fold

fold( unfold)
fold

F#

F#
.NET Framework

.NET Framework

2.0
.NET Framework

F#

.NET Framework

F# .NET Framework2.0
Runtime
.NET Framework2.0 LINQ
F # List

.NET Framework 2.0 F#

.NET Framework

4.0 F#
TDDBC Tokyo 1.6

C# ( )
KeyValueTime.cs 42
SystemClock.cs 30
TddbcKeyValueStore.cs 67

F# ( )
KeyValueStore.fs 48

C# 139 F# 48

.NET Framework

4.0 F#
TDDBC Tokyo 1.6

C# ( )
KeyValueTimeTest.cs 141
SystemClockTest.cs 34
TddbcKeyValueStoreTest.cs 346 ( )

F# ( )
KeyValueStore.fs 170

C# 521 F# 170

.NET Framework

.NET Framework F#

2.0 C#
F#

F# list F# dll

array seq

static

NewHoge
Tag
IsHoge

F#

module Hoge
let plus10 = ((+)10)
Hoge.plus10
FSharp.Core.FSharpFunc
FSharp.Core.dll

parsec
JParsec
NParsec
FParsec
scala.util.parsing
Boost.Spirit

NParsec

parsec .NET
C#
C#

Java
Scanner

NParsec

var lazyexpr = new Parser<double>[1];
var plazyexpr = Parsers.Lazy<double>(() =>
lazyexpr[0]
);
var pterm =
plazyexpr.Between(popen, pclose) | pnum;
var pexpr = ...
lazyexpr[0] = pexpr;

FParsec

let pexpr, exprref =
createParserForwardedToRef()
let pterm =
pexpr |> between popen pclose
<|> pnum
do exprref := ...

F# 10 C# 54

C#
Visitor

NParsec Bind
return Parsers.Return(...)
FParsec

仕事で使うF#

More Related Content

What's hot

Viewers also liked

Similar to 仕事で使うF#

More from bleis tift

Recently uploaded

仕事で使うF#