Merge pull request #2530 from MiYanni/OptionValueType

Add ValueType to Option

Author: MiYanni

src/System.CommandLine.ApiCompatibility.Tests/ApiCompatibilityApprovalTests.System_CommandLine_api_is_not_changed.approved.txt

@@ -1,4 +1,4 @@
-System.CommandLine
+System.CommandLine
   public abstract class Argument : Symbol
     public ArgumentArity Arity { get; set; }
     public System.Collections.Generic.List<System.Func<System.CommandLine.Completions.CompletionContext,System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem>>> CompletionSources { get; }
@@ -98,11 +98,13 @@ System.CommandLine
     public System.Boolean Recursive { get; set; }
     public System.Boolean Required { get; set; }
     public System.Collections.Generic.List<System.Action<System.CommandLine.Parsing.OptionResult>> Validators { get; }
+    public System.Type ValueType { get; }
     public System.Collections.Generic.IEnumerable<System.CommandLine.Completions.CompletionItem> GetCompletions(System.CommandLine.Completions.CompletionContext context)
   public class Option<T> : Option
     .ctor(System.String name, System.String[] aliases)
     public Func<System.CommandLine.Parsing.ArgumentResult,T> CustomParser { get; set; }
     public Func<System.CommandLine.Parsing.ArgumentResult,T> DefaultValueFactory { get; set; }
+    public System.Type ValueType { get; }
     public System.Void AcceptLegalFileNamesOnly()
     public System.Void AcceptLegalFilePathsOnly()
     public System.Void AcceptOnlyFromAmong(System.String[] values)

src/System.CommandLine/Option.cs

@@ -62,6 +62,11 @@ public ArgumentArity Arity
         /// </summary>
         public bool Recursive { get; set; }
 
+        /// <summary>
+        /// Gets the <see cref="Type" /> that the option's parsed tokens will be converted to.
+        /// </summary>
+        public abstract Type ValueType { get; }
+
         /// <summary>
         /// Validators that will be called when the option is matched by the parser.
         /// </summary>

src/System.CommandLine/Option{T}.cs

@@ -44,6 +44,9 @@ public Func<ArgumentResult, T>? DefaultValueFactory
 
         internal sealed override Argument Argument => _argument;
 
+        /// <inheritdoc />
+        public override Type ValueType => _argument.ValueType;
+
         /// <summary>
         /// Configures the option to accept only the specified values, and to suggest them as command line completions.
         /// </summary>