A little parser that handles escaping, single-, and double-quotes.

CLILikeParser.cs

/* Original code Copyright (c) 2018 Shane Celis[1]
   Licensed under the MIT License[2]

   Original code posted here[3].

   This comment generated by code-cite[4].

   [1]: https://github.com/shanecelis
   [2]: https://opensource.org/licenses/MIT
   [3]: https://gist.github.com/shanecelis/55d2d888cf57ab8ef0a3432456953281
   [4]: https://github.com/shanecelis/code-cite
*/

using System.Collections.Generic;
using Sprache;

/*
  A little parser that handles escaping, single-, and double-quotes. It's meant
  to make a quick-and-dirty Command Line Interface (CLI)-like parser.

  Also shows how one can do monadic parsing in C# using Linq syntax too.

  Examples of usage:

  CLILikeParser.ParseString(@"hello world") -> {"hello", "world"}
  CLILikeParser.ParseString(@"hello\ world") -> {"hello world"}
  CLILikeParser.ParseString(@"hello 'world'") -> {"hello", "world"}
  CLILikeParser.ParseString(@"hello 'world thing'") -> {"hello", "world thing"}
  CLILikeParser.ParseString(@"hello \"world 'thing'\"") -> {"hello", "world 'thing'"}
  CLILikeParser.ParseString(@"hello 'world \"thing\"') -> {"hello", "world \"thing\""}
*/
public static class CLILikeParser {

  // https://www.thomaslevesque.com/2017/02/23/easy-text-parsing-in-c-with-sprache/
  public static readonly Parser<char> escapedChar =
    from _ in Parse.Char('\\')
    from c in Parse.AnyChar
    select c;

  private static readonly Parser<char> _quotedText =
    Parse.AnyChar.Except(Parse.Char('\''));

  private static readonly Parser<char> _doubleQuotedText =
    Parse.AnyChar.Except(Parse.Char('"'));

  public static readonly Parser<string> quotedString =
    from open in Parse.Char('\'')
    from text in escapedChar.Or(_quotedText).Many().Text()
    from close in Parse.Char('\'')
    select text;

  public static readonly Parser<string> doubleQuotedString =
    from open in Parse.Char('"')
    from text in escapedChar.Or(_doubleQuotedText).Many().Text()
    from close in Parse.Char('"')
    select text;

  public static readonly Parser<string> bareWord =
    escapedChar.Or(Parse.CharExcept(' ')).AtLeastOnce().Text();

  public static readonly Parser<string> argument =
    from leading in Parse.WhiteSpace.Many()
    from arg in quotedString.Or(doubleQuotedString).Or(bareWord)
    select arg;

  public static readonly Parser<IEnumerable<string>> commandLine =
    from arguments in argument.Many()
    from trailing in Parse.WhiteSpace.Many()
    select arguments;

  public static IEnumerable<string> ParseString(string cmdLine) {
    return commandLine.Parse(cmdLine);
  }
}