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Using the Regex type provider

There are some nuances to using the regular expression type provider that are easy to miss. This snippet addresses them.

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/// First, you must open the FSharpx namespace, not the FSharpx.TypeProviders.Regex
/// namespace or even the FSharpx.TypeProviders namespace. (Or course, if you need
/// to reference the fully-qualified type name in order to disambiguate the Regex
/// type, be aware that it's simply "FSharpx.Regex")

open FSharpx

/// Next, define your Regex type. Remember that you're defining a type (duh!), 
/// *not* a let binding:

type NameRegex = Regex< @"(?<firstName>\p{L}+)\s+(?<lastName>\p{L}+)" >

/// Let's define a name to test
let name = "Giuseppe Verdi"

/// To test if the name matches the regular expression, use NameRegex without
/// parentheses to call the IsMatch ( string ) function:

NameRegex.IsMatch name 
|> printfn """Name.IsMatch "%s" = %b""" name

/// To parse the name, use NameRegex *with parentheses* to call the Match function. /// (You'll be instantiating a NameRegex object when you do so. Since it's not a
/// singleton, you may want to bind it to a symbol in order not to have to 
/// re-instantiate it if you use it again):

NameRegex().Match name
|> (fun m -> printfn """firstName: "%s", lastName: "%s" """ m.firstName.Value m.lastName.Value)

namespace FSharpx

type NameRegex = Regex<...>

Full name: Script.NameRegex

First, you must open the FSharpx namespace, not the FSharpx.TypeProviders.Regex
namespace or even the FSharpx.TypeProviders namespace. (Or course, if you need
to reference the fully-qualified type name in order to disambiguate the Regex
type, be aware that it's simply "FSharpx.Regex")
Next, define your Regex type. Remember that you're defining a type (duh!),
*not* a let binding:

type Regex =
  inherit Regex
  member Options : RegexOptions
  member RightToLeft : bool
  val capnames : Hashtable
  val caps : Hashtable
  val capsize : int
  val capslist : string []
  val factory : RegexRunnerFactory
  val pattern : string
  val roptions : RegexOptions
  ...

Full name: FSharpx.Regex

val name : string

Full name: Script.name

Let's define a name to test

Regex<...>.IsMatch(input: string) : bool

Indicates whether the regular expression finds a match in the specified input string
System.Text.RegularExpressions.Regex.IsMatch(input: string, pattern: string) : bool
System.Text.RegularExpressions.Regex.IsMatch(input: string, pattern: string, options: System.Text.RegularExpressions.RegexOptions) : bool

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

Full name: Microsoft.FSharp.Core.ExtraTopLevelOperators.printfn

val m : Regex<...>.MatchType

property Regex<...>.MatchType.firstName: System.Text.RegularExpressions.Group

Gets the "firstName" group from this match

property System.Text.RegularExpressions.Capture.Value: string

property Regex<...>.MatchType.lastName: System.Text.RegularExpressions.Group

Gets the "lastName" group from this match

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More information

Link:	http://fssnip.net/ny
Posted:	2 years ago
Author:	musicologyman
Tags:	type provider , type providers , regular expression , regular expressions , regex