Closes issue #88

src/SmartFormat.Tests/Extensions/IsMatchFormatterTests.cs

@@ -0,0 +1,62 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Text.RegularExpressions;
+using NUnit.Framework;
+using SmartFormat.Core.Formatting;
+using SmartFormat.Core.Settings;
+using SmartFormat.Extensions;
+
+namespace SmartFormat.Tests.Extensions
+{
+    [TestFixture]
+    public class IsMatchFormatterTests
+    {
+        private Dictionary<string, object> _variable = new Dictionary<string,object>() { {"theKey", "Some123Content"}};
+        private SmartFormatter _formatter;
+
+        public IsMatchFormatterTests()
+        {
+            _formatter = Smart.CreateDefaultSmartFormat();
+            _formatter.FormatterExtensions.Add(new IsMatchFormatter {RegexOptions = RegexOptions.CultureInvariant});
+            _formatter.Settings.FormatErrorAction = ErrorAction.ThrowError;
+        }
+
+        [TestCase("{theKey:ismatch(^.+123.+$):Okay - {}|No match content}", RegexOptions.None, "Okay - Some123Content")]
+        [TestCase("{theKey:ismatch(^.+123.+$):Fixed content if match|No match content}", RegexOptions.None, "Fixed content if match")]
+        [TestCase("{theKey:ismatch(^.+999.+$):{}|No match content}", RegexOptions.None, "No match content")]
+        [TestCase("{theKey:ismatch(^.+123.+$):|Only content with no match}", RegexOptions.None, "")]
+        [TestCase("{theKey:ismatch(^.+999.+$):|Only content with no match}", RegexOptions.None, "Only content with no match")]
+        [TestCase("{theKey:ismatch(^SOME123.+$):Okay - {}|No match content}", RegexOptions.IgnoreCase, "Okay - Some123Content")]
+        [TestCase("{theKey:ismatch(^SOME123.+$):Okay - {}|No match content}", RegexOptions.None, "No match content")]
+        public void Test_Formats_And_CaseSensitivity(string format, RegexOptions options, string expected)
+        {
+            ((IsMatchFormatter) _formatter.FormatterExtensions.First(fex =>
+                fex.GetType() == typeof(IsMatchFormatter))).RegexOptions = options;
+
+            Assert.AreEqual(expected, _formatter.Format(format, _variable));
+        }
+
+        [Test]
+        public void Test_FormatException()
+        {
+            // less than 2 format options throw exception
+            Assert.Throws<FormattingException>(() =>
+                _formatter.Format("{theKey:ismatch(^.+123.+$):Dummy content}", _variable));
+        }
+
+        [Test]
+        public void Test_List()
+        {
+            var myList = new List<int> {100, 200, 300};
+            Assert.AreEqual("100.00, 200.00 and 'no match'",
+                _formatter.Format(CultureInfo.InvariantCulture,
+                    "{0:list:{:ismatch(^100|200|999$):{:0.00}|'no match'}|, | and }", myList));
+
+            Assert.AreEqual("'match', 'match' and 'no match'",
+                _formatter.Format(CultureInfo.InvariantCulture,
+                    "{0:list:{:ismatch(^100|200|999$):'match'|'no match'}|, | and }", myList));
+        }
+    }
+}

src/SmartFormat.Tests/SmartFormat.Tests.csproj

@@ -61,6 +61,7 @@
     <Compile Include="Extensions\ChooseFormatterTests.cs" />
     <Compile Include="Extensions\ConditionalFormatterTests.cs" />
     <Compile Include="Extensions\DictionaryFormatterTests.cs" />
+    <Compile Include="Extensions\IsMatchFormatterTests.cs" />
     <Compile Include="Extensions\ListFormatterTests.cs" />
     <Compile Include="Extensions\PluralLocalizationFormatterTests.cs" />
     <Compile Include="Extensions\ReflectionFormatterTests.cs" />

src/SmartFormat/Extensions/IsMatchFormatter.cs

@@ -0,0 +1,44 @@
+using System;
+using System.Linq;
+using System.Text.RegularExpressions;
+using SmartFormat.Core.Extensions;
+
+namespace SmartFormat.Extensions
+{
+    /// <summary>
+    /// Formatter with evaluation of regular expressions.
+    /// </summary>
+    /// <remarks>
+    /// Syntax:
+    /// {value:ismatch(regex): format | default}
+    /// Or in context of a list:
+    /// {myList:list:{:ismatch(^regex$):{:format}|'no match'}|, | and }
+    /// </remarks>
+    public class IsMatchFormatter : IFormatter
+    {
+        public string[] Names { get; set; } = { "ismatch" };
+
+        public bool TryEvaluateFormat(IFormattingInfo formattingInfo)
+        {
+            var expression = formattingInfo.FormatterOptions;
+            var formats = formattingInfo.Format.Split('|');
+
+            if (formats.Count == 0)
+                return true;
+
+            if (formats.Count != 2)
+                throw new FormatException("Exactly 2 format options are required.");
+
+            var regEx = new Regex(expression, RegexOptions);
+
+            if (regEx.IsMatch(formattingInfo.CurrentValue.ToString()))
+                formattingInfo.Write(formats[0], formattingInfo.CurrentValue);
+            else if (formats.Count == 2)
+                formattingInfo.Write(formats[1], formattingInfo.CurrentValue);
+
+            return true;
+        }
+
+        public RegexOptions RegexOptions { get; set; }
+    }
+}

src/SmartFormat/SmartFormat.Net40.csproj

@@ -76,6 +76,7 @@
     <Compile Include="Extensions\DefaultFormatter.cs" />
     <Compile Include="Extensions\DefaultSource.cs" />
     <Compile Include="Extensions\DictionarySource.cs" />
+    <Compile Include="Extensions\IsMatchFormatter.cs" />
     <Compile Include="Extensions\ListFormatter.cs" />
     <Compile Include="Extensions\PluralLocalizationFormatter.cs" />
     <Compile Include="Extensions\ReflectionSource.cs" />

src/SmartFormat/SmartFormat.csproj

@@ -74,6 +74,7 @@
     <Compile Include="Extensions\DefaultFormatter.cs" />
     <Compile Include="Extensions\DefaultSource.cs" />
     <Compile Include="Extensions\DictionarySource.cs" />
+    <Compile Include="Extensions\IsMatchFormatter.cs" />
     <Compile Include="Extensions\ListFormatter.cs" />
     <Compile Include="Extensions\PluralLocalizationFormatter.cs" />
     <Compile Include="Extensions\ReflectionSource.cs" />