Add ParseArg method to split commandline

Author: moh-hassan

src/CommandLine/UnParserExtensions.cs

@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections;
+using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using CommandLine.Core;
@@ -102,6 +103,18 @@ public static string FormatCommandLine<T>(this Parser parser, T options)
             return parser.FormatCommandLine(options, config => { });
         }
 
+        /// <summary>
+        /// Format a command line argument string from a parsed instance in the form of string[]. 
+        /// </summary>
+        /// <typeparam name="T">Type of <paramref name="options"/>.</typeparam>
+        /// <param name="parser">Parser instance.</param>
+        /// <param name="options">A parsed (or manually correctly constructed instance).</param>
+        /// <returns>A string[] with command line arguments.</returns>
+        public static string[] FormatCommandLineArgs<T>(this Parser parser, T options)
+        {
+            return parser.FormatCommandLine(options, config => { }).SplitArgs();
+        }
+
         /// <summary>
         /// Format a command line argument string from a parsed instance. 
         /// </summary>
@@ -180,7 +193,19 @@ orderby v.Index
             return builder
                 .ToString().TrimEnd(' ');
         }
-
+        /// <summary>
+        /// Format a command line argument string[] from a parsed instance. 
+        /// </summary>
+        /// <typeparam name="T">Type of <paramref name="options"/>.</typeparam>
+        /// <param name="parser">Parser instance.</param>
+        /// <param name="options">A parsed (or manually correctly constructed instance).</param>
+        /// <param name="configuration">The <see cref="Action{UnParserSettings}"/> lambda used to configure
+        /// aspects and behaviors of the unparsersing process.</param>
+        /// <returns>A string[] with command line arguments.</returns>
+        public static string[] FormatCommandLineArgs<T>(this Parser parser, T options, Action<UnParserSettings> configuration)
+        {
+            return FormatCommandLine<T>(parser, options, configuration).SplitArgs();
+        }
         private static string FormatValue(Specification spec, object value)
         {
             var builder = new StringBuilder();
@@ -273,5 +298,35 @@ private static bool IsEmpty(this object value, Specification specification, bool
             if (value is IEnumerable && !((IEnumerable)value).GetEnumerator().MoveNext()) return true;
             return false;
         }
+
+
+        #region splitter
+        /// <summary>
+        /// Returns a string array that contains the substrings in this instance that are delimited by space considering string between double quote.
+        /// </summary>
+        /// <param name="command">the commandline string</param>
+        /// <param name="keepQuote">don't remove the quote</param>
+        /// <returns>a string array that contains the substrings in this instance</returns>
+        public static string[] SplitArgs(this string command, bool keepQuote = false)
+        {
+            if (string.IsNullOrEmpty(command))
+                return new string[0];
+
+            var inQuote = false;
+            var chars = command.ToCharArray().Select(v =>
+            {
+                if (v == '"')
+                    inQuote = !inQuote;
+                return !inQuote && v == ' ' ? '\n' : v;
+            }).ToArray();
+
+            return new string(chars).Split('\n')
+                .Select(x => keepQuote ? x : x.Trim('"'))
+                .Where(x => !string.IsNullOrWhiteSpace(x))
+                .ToArray();
+        }
+
+        #endregion
+
     }
 }

tests/CommandLine.Tests/Unit/UnParserExtensionsTests.cs

@@ -250,6 +250,30 @@ public static void UnParsing_instance_with_nullable_bool(bool? flag, string expe
                 .FormatCommandLine(options)
                 .Should().BeEquivalentTo(expected);
         }
+        #region SplitArgs
+        [Theory]
+        [InlineData("--shape Circle", new[] { "--shape","Circle" })]
+        [InlineData("  --shape     Circle  ", new[] { "--shape", "Circle" })]
+        [InlineData("-a --shape Circle", new[] {"-a", "--shape", "Circle" })]
+        [InlineData("-a --shape Circle -- -x1 -x2", new[] { "-a", "--shape", "Circle","--","-x1","-x2" })]
+        [InlineData("--name \"name with space and quote\" -x1", new[] { "--name", "name with space and quote","-x1" })]       
+        public static void Split_arguments(string command, string[] expectedArgs)
+        {
+            var args = command.SplitArgs();
+            args.Should().BeEquivalentTo(expectedArgs);
+        }
+        [Theory]
+        [InlineData("--shape Circle", new[] { "--shape", "Circle" })]
+        [InlineData("  --shape     Circle  ", new[] { "--shape", "Circle" })]
+        [InlineData("-a --shape Circle", new[] { "-a", "--shape", "Circle" })]
+        [InlineData("-a --shape Circle -- -x1 -x2", new[] { "-a", "--shape", "Circle", "--", "-x1", "-x2" })]
+        [InlineData("--name \"name with space and quote\" -x1", new[] { "--name", "\"name with space and quote\"", "-x1" })]
+        public static void Split_arguments_with_keep_quote(string command, string[] expectedArgs)
+        {
+            var args = command.SplitArgs(true);
+            args.Should().BeEquivalentTo(expectedArgs);
+        }
+        #endregion
         class Option_Int_Nullable
         {
             [Option('v', Default = 1)]