Add support for parsing multiple types of quotation marks in commands, Fix #942 (#943)

* Add ability to support different types of quotation marks

* Added normal quotation mark to list of aliases, removed single quote mark

* clean up leftover changes from testing

* change quotation mark parsing to use a map of matching pairs

* remove commented out code

* Fix conventions of the command parser utility functions

* change storage type of alias dictionary to be IReadOnlyDictionary

* revert type of CommandServiceConfig QuotationMarkAliasMap to Dictionary

* minor formatting changes to CommandParser

* remove unnecessary whitespace

* Move aliases outside of CommandInfo class

* copy IReadOnlyDictionary to ImmutableDictionary

* minor syntax changes in CommandServiceConfig

* add newline before namespace for consistency

* newline formatting tweak

* simplification of GetMatch method for CommandParser

* add more quote unicode punctuation pairs

* add check for null value when building ImmutableDictionary

* Move default alias map into a separate source file

* Ensure that the collection passed into command service is not null

src/Discord.Net.Commands/CommandParser.cs

@@ -1,4 +1,5 @@
-using System;
+using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Text;
 using System.Threading.Tasks;
@@ -13,8 +14,7 @@ namespace Discord.Commands
             Parameter,
             QuotedParameter
         }
-        
+        public static async Task<ParseResult> ParseArgsAsync(CommandInfo command, ICommandContext context, bool ignoreExtraArgs, IServiceProvider services, string input, int startPos, IReadOnlyDictionary<char, char> aliasMap)
-        public static async Task<ParseResult> ParseArgsAsync(CommandInfo command, ICommandContext context, IServiceProvider services, string input, int startPos)
         {
             ParameterInfo curParam = null;
             StringBuilder argBuilder = new StringBuilder(input.Length);
@@ -24,7 +24,27 @@ namespace Discord.Commands
             var argList = ImmutableArray.CreateBuilder<TypeReaderResult>();
             var paramList = ImmutableArray.CreateBuilder<TypeReaderResult>();
             bool isEscaping = false;
-            char c;
+            char c, matchQuote = '\0';
+
+            // local helper functions
+            bool IsOpenQuote(IReadOnlyDictionary<char, char> dict, char ch)
+            {
+                // return if the key is contained in the dictionary if it is populated
+                if (dict.Count != 0)
+                    return dict.ContainsKey(ch);
+                // or otherwise if it is the default double quote
+                return c == '\"';
+            }
+
+            char GetMatch(IReadOnlyDictionary<char, char> dict, char ch)
+            {
+                // get the corresponding value for the key, if it exists
+                // and if the dictionary is populated
+                if (dict.Count != 0 && dict.TryGetValue(c, out var value))
+                    return value;
+                // or get the default pair of the default double quote
+                return '\"';
+            }
 
             for (int curPos = startPos; curPos <= endPos; curPos++)
             {
@@ -74,9 +94,11 @@ namespace Discord.Commands
                             argBuilder.Append(c);
                             continue;
                         }
-                        if (c == '\"')
+                        
+                        if (IsOpenQuote(aliasMap, c))
                         {
                             curPart = ParserPart.QuotedParameter;
+                            matchQuote = GetMatch(aliasMap, c);
                             continue;
                         }
                         curPart = ParserPart.Parameter;
@@ -97,7 +119,7 @@ namespace Discord.Commands
                 }
                 else if (curPart == ParserPart.QuotedParameter)
                 {
-                    if (c == '\"')
+                    if (c == matchQuote)
                     {
                         argString = argBuilder.ToString(); //Remove quotes
                         lastArgEndPos = curPos + 1;

src/Discord.Net.Commands/CommandService.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Collections.Immutable;
@@ -32,6 +32,7 @@ namespace Discord.Commands
         internal readonly RunMode _defaultRunMode;
         internal readonly Logger _cmdLogger;
         internal readonly LogManager _logManager;
+        internal readonly IReadOnlyDictionary<char, char> _quotationMarkAliasMap;
 
         public IEnumerable<ModuleInfo> Modules => _moduleDefs.Select(x => x);
         public IEnumerable<CommandInfo> Commands => _moduleDefs.SelectMany(x => x.Commands);
@@ -45,6 +46,7 @@ namespace Discord.Commands
             _ignoreExtraArgs = config.IgnoreExtraArgs;
             _separatorChar = config.SeparatorChar;
             _defaultRunMode = config.DefaultRunMode;
+            _quotationMarkAliasMap = (config.QuotationMarkAliasMap ?? new Dictionary<char, char>()).ToImmutableDictionary();
             if (_defaultRunMode == RunMode.Default)
                 throw new InvalidOperationException("The default run mode cannot be set to Default.");
 
@@ -337,7 +339,6 @@ namespace Discord.Commands
         public async Task<IResult> ExecuteAsync(ICommandContext context, string input, IServiceProvider services, MultiMatchHandling multiMatchHandling = MultiMatchHandling.Exception)
         {
             services = services ?? EmptyServiceProvider.Instance;
-
             var searchResult = Search(context, input);
             if (!searchResult.IsSuccess)
                 return searchResult;

src/Discord.Net.Commands/CommandServiceConfig.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 
 namespace Discord.Commands
 {
@@ -18,6 +19,10 @@ namespace Discord.Commands
         /// <summary> Determines whether RunMode.Sync commands should push exceptions up to the caller. </summary>
         public bool ThrowOnError { get; set; } = true;
 
+        /// <summary> Collection of aliases that can wrap strings for command parsing. 
+        /// represents the opening quotation mark and the value is the corresponding closing mark.</summary>
+        public Dictionary<char, char> QuotationMarkAliasMap { get; set; } = QuotationAliasUtils.GetDefaultAliasMap;
+
         /// <summary> Determines whether extra parameters should be ignored. </summary>
         public bool IgnoreExtraArgs { get; set; } = false;
     }

src/Discord.Net.Commands/Info/CommandInfo.cs

@@ -1,4 +1,4 @@
-using Discord.Commands.Builders;
+using Discord.Commands.Builders;
 using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
@@ -121,7 +121,8 @@ namespace Discord.Commands
                 return ParseResult.FromError(preconditionResult);
 
             string input = searchResult.Text.Substring(startIndex);
-            return await CommandParser.ParseArgsAsync(this, context, services, input, 0).ConfigureAwait(false);
+
+            return await CommandParser.ParseArgsAsync(this, context, _commandService._ignoreExtraArgs, services, input, 0, _commandService._quotationMarkAliasMap).ConfigureAwait(false);
         }
 
         public Task<IResult> ExecuteAsync(ICommandContext context, ParseResult parseResult, IServiceProvider services)

src/Discord.Net.Commands/Utilities/QuotationAliasUtils.cs

@@ -0,0 +1,95 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Globalization;
+
+namespace Discord.Commands
+{
+    /// <summary>
+    /// Utility methods for generating matching pairs of unicode quotation marks for CommandServiceConfig
+    /// </summary>
+    internal static class QuotationAliasUtils
+    {
+        /// <summary>
+        /// Generates an IEnumerable of characters representing open-close pairs of
+        /// quotation punctuation.
+        /// </summary>
+        internal static Dictionary<char, char> GetDefaultAliasMap
+        {
+            get
+            {
+                // Output of a gist provided by https://gist.github.com/ufcpp
+                // https://gist.github.com/ufcpp/5b2cf9a9bf7d0b8743714a0b88f7edc5
+                // This was not used for the implementation because of incompatibility with netstandard1.1
+                return new Dictionary<char, char> {
+                    {'\"', '\"' },
+                    {'«', '»' },
+                    {'‘', '’' },
+                    {'“', '”' },
+                    {'„', '‟' },
+                    {'‹', '›' },
+                    {'‚', '‛' },
+                    {'《', '》' },
+                    {'〈', '〉' },
+                    {'「', '」' },
+                    {'『', '』' },
+                    {'〝', '〞' },
+                    {'﹁', '﹂' },
+                    {'﹃', '﹄' },
+                    {'＂', '＂' },
+                    {'＇', '＇' },
+                    {'｢', '｣' },
+                    {'(', ')' },
+                    {'༺', '༻' },
+                    {'༼', '༽' },
+                    {'᚛', '᚜' },
+                    {'⁅', '⁆' },
+                    {'⌈', '⌉' },
+                    {'⌊', '⌋' },
+                    {'❨', '❩' },
+                    {'❪', '❫' },
+                    {'❬', '❭' },
+                    {'❮', '❯' },
+                    {'❰', '❱' },
+                    {'❲', '❳' },
+                    {'❴', '❵' },
+                    {'⟅', '⟆' },
+                    {'⟦', '⟧' },
+                    {'⟨', '⟩' },
+                    {'⟪', '⟫' },
+                    {'⟬', '⟭' },
+                    {'⟮', '⟯' },
+                    {'⦃', '⦄' },
+                    {'⦅', '⦆' },
+                    {'⦇', '⦈' },
+                    {'⦉', '⦊' },
+                    {'⦋', '⦌' },
+                    {'⦍', '⦎' },
+                    {'⦏', '⦐' },
+                    {'⦑', '⦒' },
+                    {'⦓', '⦔' },
+                    {'⦕', '⦖' },
+                    {'⦗', '⦘' },
+                    {'⧘', '⧙' },
+                    {'⧚', '⧛' },
+                    {'⧼', '⧽' },
+                    {'⸂', '⸃' },
+                    {'⸄', '⸅' },
+                    {'⸉', '⸊' },
+                    {'⸌', '⸍' },
+                    {'⸜', '⸝' },
+                    {'⸠', '⸡' },
+                    {'⸢', '⸣' },
+                    {'⸤', '⸥' },
+                    {'⸦', '⸧' },
+                    {'⸨', '⸩' },
+                    {'【', '】'},
+                    {'〔', '〕' },
+                    {'〖', '〗' },
+                    {'〘', '〙' },
+                    {'〚', '〛' }
+                };
+            }
+        }
+    }
+}