F# Development

CommandLineParser provides F# package CommandLineParser.FSharp published to nuget. To install, type the command:

PM> Install-Package CommandLineParser.FSharp

The package has a dependency on: FSharp.Core.

You can use all the features of c# package without limitation.

F# tutorial step by step:

1- Declare the option class use OptionAttribute and ValueAttribute to annotate the properties of the class. Also you can define property as option.

type options = {
  [<Option('r', "read", Required = true, HelpText = "Input files.")>] files : string;
  [<Option(HelpText = "Prints all messages to standard output.")>] verbose : bool;
  [<Option(Default = "english", HelpText = "Content language.")>] language : string;  
  [<Value(0, MetaName="offset", HelpText = "File offset.")>] offset : int option;
}

2- handle Parser Success

let run (o : options)  =
    printfn "Parser success"
    printfn "files= %A verbose= %b language= %s offset= %i" o.files o.verbose o.language o.offset.Value

3- Handle Parser Failure

let fail (e : IEnumerable<Error>)  =
    printfn "fail"

4- Call Parser

let main argv =
  printfn "Args= %A" argv
  let result = CommandLine.Parser.Default.ParseArguments<options>(argv)
  match result with
  | :? Parsed<options> as parsed -> run parsed.Value
  | :? NotParsed<options> as notParsed -> fail notParsed.Errors

Complete Example:

Click to expand!

type options = {
  [<Option('r', "read", Required = true, HelpText = "Input files.")>] files : string;
  [<Option(HelpText = "Prints all messages to standard output.")>] verbose : bool;
  [<Option(Default = "english", HelpText = "Content language.")>] language : string;  
  [<Value(0, MetaName="offset", HelpText = "File offset.")>] offset : int option;
}

let run (o : options)  =
    printfn "Parser success"
    printfn "files= %A verbose= %b language= %s offset= %i" 
      o.files o.verbose o.language o.offset.Value
    

let fail (e : IEnumerable<Error>)  =
    printfn "fail"
  
    
let main argv =
  printfn "Args= %A" argv
  let result = CommandLine.Parser.Default.ParseArguments<options>(argv)
  match result with
  | :? Parsed<options> as parsed -> run parsed.Value
  | :? NotParsed<options> as notParsed -> fail notParsed.Errors  

Download a complete demo from the Project Repository.