namespace Microsoft.FSharp
type Users = obj

Full name: typeproviders.Users
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val string : value:'T -> string

Full name: Microsoft.FSharp.Core.Operators.string

--------------------
type string = System.String

Full name: Microsoft.FSharp.Core.string
namespace Microsoft.FSharp.Data
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type LiteralAttribute =
  inherit Attribute
  new : unit -> LiteralAttribute

Full name: Microsoft.FSharp.Core.LiteralAttribute

--------------------
new : unit -> LiteralAttribute
val printfn : format:Printf.TextWriterFormat<'T> -> 'T

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printfn
val box : value:'T -> obj

Full name: Microsoft.FSharp.Core.Operators.box
Multiple items
val int : value:'T -> int (requires member op_Explicit)

Full name: Microsoft.FSharp.Core.Operators.int

--------------------
type int = int32

Full name: Microsoft.FSharp.Core.int

--------------------
type int<'Measure> = int

Full name: Microsoft.FSharp.Core.int<_>
Multiple items
val float : value:'T -> float (requires member op_Explicit)

Full name: Microsoft.FSharp.Core.Operators.float

--------------------
type float = System.Double

Full name: Microsoft.FSharp.Core.float

--------------------
type float<'Measure> = float

Full name: Microsoft.FSharp.Core.float<_>

F# Type Providers

The Current State

Sergey Tihon

@sergey_tihon

What are Type Providers?

(In F# since v3.0, August 2012)

Classic TP intro from Don Syme

  • The world is information-rich
  • Modern applications are information-rich
  • Our languages are information-sparse
This is a problem!

CodeGen - the classic approach

Source

CodeGen

Code

WCF

=>

svcutil.exe

=>

T1

SQL DB

=>

edmgen.exe

=>

T2

OData

=>

datrasvcutil.exe

=>

T3

A Type Provider is ...

... a component that provides types, properties, and methods for use in your program.

As well as a compiler/IDE extension…

JSON Type Provider

JSON

Which Type Provides exist?

F# 3.0 Built-in Type Provides

  • WsdlService
  • EdmxFile
  • ODataService
  • DbmlFile (DBML file based)
  • SqlDataConnection (LINQ to SQL)
  • SqlEntityConnection (LINQ to Entities)

FSharp.Data

  • CSV Type Provider
  • HTML Type Provider
  • JSON Type Provider
  • XML Type Provider
  • WorldBank Provider
  • Freebase Provider

FSharp.Data

WorldBank Type Provider

WB

FSharp.Management

  • FileSystem
  • Registry
  • WMI
  • PowerShell
  • SystemTimeZonesProvider

FSharp.Management

FileSystem Type Provider

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// reference the type provider dll
#r "FSharp.Management.dll"
open FSharp.Management

// Let the type provider do its work
type Users = FileSystem<"C:\\Users\\">

// now you have typed access to your filesystem 
// and you can browse it via Intellisense
Users.AllUsers.Path

val it : string = "C:\Users\All Users"

FileSystem TP is awesome for Unit Tests

FileSystemTPforTests

Unit tests from Stanford.NLP.NET

PowerShell Type Provider

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#r "System.Management.Automation.dll"
#r "FSharp.Management.PowerShell.dll"
open FSharp.Management

type PS = PowerShellProvider< "Microsoft.PowerShell.Management" >

PowerShell

FSharp.Data.SqlClient

  • SqlCommandProvider - type-safe access to full set of T-SQL language
  • SqlProgrammabilityProvider - quick access to Sql Server functions, stored procedures and tables in idiomatic F# way
  • SqlEnumProvider - generates enumeration types based on static lookup data from any ADO.NET complaint source

FSharp.Data.SqlClient

SqlCommandProvider

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open FSharp.Data

[<Literal>]
let connectionString = 
  @"Data Source=.;Initial Catalog=AdventureWorks2014;Integrated Security=True"
    
do
  use cmd = new SqlCommandProvider<"
      SELECT TOP(@topN) FirstName, LastName, SalesYTD 
      FROM Sales.vSalesPerson
      WHERE CountryRegionName = @regionName AND SalesYTD > @salesMoreThan 
      ORDER BY SalesYTD
      " , connectionString>()

  cmd.Execute(topN=3L, regionName="United States", salesMoreThan=1000000M) 
  |> printfn "%A"

R Provider

The F# Type Provider is a mechanism that enables smooth interoperability between F# and R. The Type Provider discovers R packages that are available in your R installation and makes them available as .NET namespaces underneath the parent namespace RProvider.

RProvider

R Provider : Linear regression

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// Random number generator
let rng = Random()
let rand () = rng.NextDouble()

// Generate fake X1 and X2 
let X1s = [ for i in 0 .. 9 -> 10. * rand () ]
let X2s = [ for i in 0 .. 9 -> 5. * rand () ]

// Build Ys, following the "true" model
let Ys = [ for i in 0 .. 9 -> 
            5. + 3. * X1s.[i] - 2. * X2s.[i] + rand () ]

let dataset =
    namedParams [
        "Y", box Ys;
        "X1", box X1s;
        "X2", box X2s; ]
    |> R.data_frame

let result = R.lm(formula = "Y~X1+X2", data = dataset)

FSharp.Configuration

  • AppSettings
  • ResX
  • Yaml
  • Ini

FSharp.Configuration

Yaml Type Provider

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Mail:
    Smtp:
        Host: smtp.sample.com
        Port: 25
        User: user1
        Password: pass1
DB:
    ConnectionString: ...
    NumberOfDeadlockRepeats: 5
    DefaultTimeout: 00:05:00

YamlConfigProvider

What else exist

  • Apiary
  • Freebase
  • Excel
  • Graph
  • Math
  • Xaml
  • CRM
  • DbPedia
  • Twitter
  • RSS
  • NuGet
  • DGML
  • DataStore
  • Hadoop/Hive/Hdfs
  • MiniCvs
  • COM
  • FunScript
  • Matlab
  • IKVM
  • Python
  • Azure
  • S3
  • Neo4j
  • Swagger (WIP)

Swagger Type Provider (WIP)

Swagger

Welcome to join development

Swagger Sample (WIP)

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#r "SwaggerProvider.dll"
open SwaggerProvider

[<Literal>]
let apiSchemaUrl = "http://petstore.swagger.io/v2/swagger.json"
let PetStore = SwaggerProvider<apiSchemaUrl>

SwaggerDemo

Type Provider Games!

Created by Ross McKinlay

Cool

2048

2048

MineSweeper

MineSweeper

The North Pole Type Provider

NPTP

Created for F# Advent Calendar in English 2014

Choose Your Own Adventure Type Provider

CYOATP

The Don Syme type provider

DSTP

How Type Providers work?

F# Code Quotations : Basics

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let a = 42
//val a : int = 42

let b = <@ 42 @>
//val b : Quotations.Expr<int> = Value (42)

let c = <@@ 42 @@>
//val c : Quotations.Expr = Value (42)

let d = <@ 2+2 @>
//val d : Quotations.Expr<int> =
//  Call (None, op_Multiply, [Value (2), Value (2)])

F# Code Quotations

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let f =
    <@ let rec g x =
        match x with
        | 0 -> 1
        | _ -> x * g(x-1)
    g 5@>

Quotations1

F# Code Quotations : Splicing

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let f3 n =
    <@ let rec g = function
        | 0 -> 1
        | x -> x * g(x-1)
    g %n@>

let combined_quotation =
    f3 <@ 3 @>

Quotations2

F# Type Provider Starter Pack

TPSP

https://github.com/fsprojects/FSharp.TypeProviders.StarterPack

Custom Zip TP

Zip1

Custom Zip TP

Zip2

Zip TP Sample

Zip3

Generated vs erased type providers

What's new in F# 4.0

(Recently released : 20 Jul 2015)

Support for static parametes to

provided methods

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ProvidedType.ProvidedMethod<staticParam>
        (providedParam1,..., providedParamM) -> returnType
  • Provided method can change its number of parameters with the static parameter given to the method.
  • The return type can likewise be changed (and can be a provided type which name depends on the input parameter) 
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let x = ExampleType()

let v1:int   = x.Average<1>(1) 
let v2:float = x.Average<2>(1,2) 
let v3:float = x.Average<3>(1,2,3)

Opportunity #1 : Regular Expressions

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let [<Literal>] phonePattern =
    @"^(?:(?<AreaCode>\d{3})-)?(?<PhoneNumber>\d{3}-\d{4})$"

Traditional usage

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type PhoneReg = RegexTyped<phonePattern>
let phone = PhoneReg()
phone.Match("800-374-2774").PhoneNumber

F# 4.0 usage

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RegexTyped.Match<phonePattern>("800-374-2774").PhoneNumber

Lincoln Atkinson presented this demo in Six Quick Picks from F# 4.0

Opportunity #2 : SafeString

A simple example is a provided safe string type which enforces that the number of slots in a String.Format format string matches the number of arguments passed.

staticmeth.png

Sample from Announcement of F# 4.0 preview

Opportunity #3 : SqlCommandProvider

SqlCommandProvider from FSharp.Data.SqlClient

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type MyCommand1 = SqlCommandProvider<"SELECT 42", connStr> 
type MyCommand2 = SqlCommandProvider<"SELECT 43", connStr>

can be rewritten as

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type MyDb = SqlCommandProvider<connStr>

type MyCommand1 = MyDb.GetCommand<"SELECT 42"> 
type MyCommand2 = MyDb.GetCommand<"SELECT 43">

Benefits:

  • Shared DB definition
  • Shared provided types

Sample provided by Dmitry Morozov

Opportunity #4: CSV Data manipulation

A modified CSV type provider that lets you add a column.

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type MyCsvFile = FSharp.Data.CsvProvider<"mycsv.csv">

let csvData = MyCsvFile.LoadSample()
[ for row in csvData -> row.Column1, row.Column2 ]

let newCsvData = csvData.WithColumn<"Column3", "int">()  
[ for row in newCsvData -> row.Column1, row.Column2, row.Column3 ]

Don Syme's sample from SampleMethStaticParamProvider

Opportunity #5: Search in the

Freebase or DbPedia provider

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type DbPedia = DbPediaProvider<"Some Parameters">

let ctxt = DbPedia.GetDataContext()

let princeTheMusician = ctxt.Ontology.People.Search<"Prince">.

In the intellisense at the last point the completions for all people matching "Prince" would be shown

Don Syme's sample from SampleMethStaticParamProvider

Opportunity #6

Any your ...

amazing

... idea

Questions?

Thanks

@sergey_tihon specially for fpconf.ru

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