globalization: complex ToString and Parse

Signed-off-by: Christoph Ruegg <git@cdrnet.ch>

src/Numerics/Complex.cs

@@ -29,9 +29,9 @@
 namespace MathNet.Numerics
 {
     using System;
+    using System.Collections.Generic;
     using System.Runtime.InteropServices;
     using System.Text;
-    using System.Text.RegularExpressions;
     using Properties;
 
     /// <summary>
@@ -73,14 +73,6 @@ namespace MathNet.Numerics
     {
         #region fields
 
-        /// <summary>
-        /// Regular expression used to parse strings into complex numbers.
-        /// </summary>
-        private static readonly Regex _parseExpression =
-            new Regex(
-                @"^((?<r>(([-+]?(\d+\.?\d*|\d*\.?\d+)([Ee][-+]?[0-9]+)?)|(NaN)|([-+]?Infinity)))|(?<i>(([-+]?((\d+\.?\d*|\d*\.?\d+)([Ee][-+]?[0-9]+)?)|(NaN)|([-+]?Infinity))?[i]))|(?<r>(([-+]?(\d+\.?\d*|\d*\.?\d+)([Ee][-+]?[0-9]+)?)|(NaN)|([-+]?Infinity)))(?<i>(([-+]((\d+\.?\d*|\d*\.?\d+)([Ee][-+]?[0-9]+)?)|[-+](NaN)|([-+]Infinity))?[i])))$",
-                RegexOptions.Singleline | RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);
-
         /// <summary>
         /// Represents imaginary unit number.
         /// </summary>
@@ -121,7 +113,7 @@ namespace MathNet.Numerics
         #region Constructor
 
         /// <summary>
-        /// Initializes a new instance of the Complex struct with the given real
+        /// Initializes a new instance of the Complex structure with the given real
         /// and imaginary parts.
         /// </summary>
         /// <param name="real">
@@ -149,8 +141,7 @@ namespace MathNet.Numerics
         /// infinite real and imaginary part. If you need more formal complex
         /// number handling (according to the Riemann Sphere and the extended
         /// complex plane C*, or using directed infinity) please check out the
-        /// alternative MathNet.PreciseNumerics and MathNet.Symbolics packages
+        /// alternative Math.NET symbolics packages instead.
-        /// instead.
         /// </remarks>
         /// <value>A value representing the infinity value.</value>
         public static Complex Infinity
@@ -242,10 +233,13 @@ namespace MathNet.Numerics
         }
 
         /// <summary>
-        /// Gets a value indicating whether the provided <c>Complex</c> evaluates to a
+        /// Gets a value indicating whether the provided <c>Complex</c>evaluates
-        /// value that is not a number.
+        /// to a value that is not a number.
         /// </summary>
-        /// <value><c>true</c> if this instance is NaN; otherwise, <c>false</c>.</value>
+        /// <value>
+        /// <c>true</c> if this instance is <see cref="NaN"/>; otherwise,
+        /// <c>false</c>.
+        /// </value>
         public bool IsNaN
         {
             get { return double.IsNaN(_real) || double.IsNaN(_imag); }
@@ -644,14 +638,16 @@ namespace MathNet.Numerics
         /// </param>
         public string ToString(string format, IFormatProvider formatProvider)
         {
+            var numberFormatInfo = formatProvider.GetNumberFormatInfo();
+
             if (IsNaN)
             {
-                return "NaN";
+                return numberFormatInfo.NaNSymbol;
             }
 
             if (IsInfinity)
             {
-                return "Infinity";
+                return numberFormatInfo.PositiveInfinitySymbol;
             }
 
             var ret = new StringBuilder();
@@ -678,6 +674,11 @@ namespace MathNet.Numerics
                 ret.Append(_imag.ToString(format, formatProvider)).Append("i");
             }
 
+            if (ret.Length == 0)
+            {
+                ret.Append((0.0).ToString(format, formatProvider));
+            }
+
             return ret.ToString();
         }
 
@@ -1041,9 +1042,9 @@ namespace MathNet.Numerics
         #region Parse Functions
 
         /// <summary>
-        /// Creates a complex number based on a string. The string can be in the following
+        /// Creates a complex number based on a string. The string can be in the
-        /// formats(without the quotes): 'n', 'ni', 'n +/- ni', 'n,n', 'n,ni,' '(n,n)', or
+        /// following formats (without the quotes): 'n', 'ni', 'n +/- ni',
-        /// '(n,ni)', where n is a real number.
+        /// 'ni +/- n', 'n,n', 'n,ni,' '(n,n)', or '(n,ni)', where n is a double.
         /// </summary>
         /// <returns>
         /// A complex number containing the value specified by the given string.
@@ -1057,9 +1058,9 @@ namespace MathNet.Numerics
         }
 
         /// <summary>
-        /// Creates a complex number based on a string. The string can be in the following
+        /// Creates a complex number based on a string. The string can be in the
-        /// formats(without the quotes): 'n', 'ni', 'n +/- ni', 'n,n', 'n,ni,' '(n,n)', or
+        /// following formats (without the quotes): 'n', 'ni', 'n +/- ni',
-        /// '(n,ni)', where n is a double.
+        /// 'ni +/- n', 'n,n', 'n,ni,' '(n,n)', or '(n,ni)', where n is a double.
         /// </summary>
         /// <returns>
         /// A complex number containing the value specified by the given string.
@@ -1068,7 +1069,8 @@ namespace MathNet.Numerics
         /// the string to parse.
         /// </param>
         /// <param name="formatProvider">
-        /// An <see cref="IFormatProvider"/> that supplies culture-specific formatting information.
+        /// An <see cref="IFormatProvider"/> that supplies culture-specific
+        /// formatting information.
         /// </param>
         public static Complex Parse(string value, IFormatProvider formatProvider)
         {
@@ -1083,8 +1085,6 @@ namespace MathNet.Numerics
                 throw new FormatException();
             }
 
-            value = value.Replace(" ", string.Empty);
-
             // strip out parens
             if (value.StartsWith("(", StringComparison.Ordinal))
             {
@@ -1093,77 +1093,137 @@ namespace MathNet.Numerics
                     throw new FormatException();
                 }
 
-                value = value.Substring(1, value.Length - 2);
+                value = value.Substring(1, value.Length - 2).Trim();
             }
 
-            // check if one character strings are valid
+            // keywords
-            if (value.Length == 1)
+            var numberFormatInfo = formatProvider.GetNumberFormatInfo();
-            {
+            var textInfo = formatProvider.GetTextInfo();
-                if (String.Compare(value, "i", StringComparison.OrdinalIgnoreCase) == 0)
+            var keywords =
+                new[]
                 {
-                    return new Complex(0, 1);
+                    textInfo.ListSeparator, numberFormatInfo.NaNSymbol,
-                }
+                    numberFormatInfo.NegativeInfinitySymbol, numberFormatInfo.PositiveInfinitySymbol,
-
+                    "+", "-", "i", "j"
-                return new Complex(Double.Parse(value, formatProvider), 0.0);
+                };
+
+            // lexing
+            var tokens = new LinkedList<string>();
+            GlobalizationHelper.Tokenize(tokens.AddFirst(value), keywords, 0);
+            var token = tokens.First;
+
+            // parse the left part
+            bool isLeftPartImaginary;
+            double leftPart = ParsePart(ref token, out isLeftPartImaginary, formatProvider);
+            if (token == null)
+            {
+                return isLeftPartImaginary ? new Complex(0, leftPart) : new Complex(leftPart, 0);
             }
 
-            if (value.Equals("-i"))
+            // parse the right part
+            if (token.Value == textInfo.ListSeparator)
             {
-                return new Complex(0, -1);
+                // format: real,imag
-            }
+                token = token.Next;
 
-            var real = 0.0;
+                if (isLeftPartImaginary)
-            var imag = 0.0;
+                {
+                    // left must not contain 'i', right doesn't matter.
+                    throw new FormatException();
+                }
 
-            var index = value.IndexOf(',');
+                bool isRightPartImaginary;
+                double rightPart = ParsePart(ref token, out isRightPartImaginary, formatProvider);
 
-            if (index > -1)
+                return new Complex(leftPart, rightPart);
+            }
+            else
             {
-                real = double.Parse(value.Substring(0, index), formatProvider);
+                // format: real + imag
-                var imagStr = value.Substring(index + 1, value.Length - index - 1);
+                bool isRightPartImaginary;
-                if (imagStr.EndsWith("i"))
+                double rightPart = ParsePart(ref token, out isRightPartImaginary, formatProvider);
+
+                if (!(isLeftPartImaginary ^ isRightPartImaginary))
                 {
-                    imagStr = imagStr.Substring(0, imagStr.Length - 1);
+                    // either left or right part must contain 'i', but not both.
+                    throw new FormatException();
                 }
 
-                imag = double.Parse(imagStr, formatProvider);
+                return isLeftPartImaginary ? new Complex(rightPart, leftPart) : new Complex(leftPart, rightPart);
             }
-            else
+        }
+
+        /// <summary>
+        /// Parse a part (real or complex) from a complex number.
+        /// </summary>
+        /// <param name="token">Start Token.</param>
+        /// <param name="imaginary">Is set to <c>true</c> if the part identified itself as being imaginary.</param>
+        /// <param name="format">
+        /// An <see cref="IFormatProvider"/> that supplies culture-specific
+        /// formatting information.
+        /// </param>
+        /// <returns>Resulting part as double.</returns>
+        /// <exception cref="FormatException"/>
+        private static double ParsePart(ref LinkedListNode<string> token, out bool imaginary, IFormatProvider format)
+        {
+            imaginary = false;
+            if (token == null)
+            {
+                throw new FormatException();
+            }
+
+            // handle prefix modifiers
+            if (token.Value == "+")
             {
-                var matchResult = _parseExpression.Match(value);
+                token = token.Next;
-                if (matchResult.Success)
+
+                if (token == null)
                 {
-                    var realStr = matchResult.Groups["r"].Value;
+                    throw new FormatException();
-                    if (!string.IsNullOrEmpty(realStr))
+                }
-                    {
+            }
-                        if (realStr.StartsWith("+"))
-                        {
-                            realStr = realStr.Substring(1);
-                        }
 
-                        real = double.Parse(realStr, formatProvider);
+            bool negative = false;
-                    }
+            if (token.Value == "-")
+            {
+                negative = true;
+                token = token.Next;
 
-                    var imagStr = matchResult.Groups["i"].Value;
+                if (token == null)
+                {
+                    throw new FormatException();
+                }
+            }
 
-                    if (!string.IsNullOrEmpty(imagStr))
+            // handle prefix imaginary symbol
-                    {
+            if (String.Compare(token.Value, "i", StringComparison.OrdinalIgnoreCase) == 0
-                        if (imagStr.StartsWith("+"))
+                || String.Compare(token.Value, "j", StringComparison.OrdinalIgnoreCase) == 0)
-                        {
+            {
-                            imagStr = imagStr.Substring(1);
+                imaginary = true;
-                        }
+                token = token.Next;
 
-                        imagStr = imagStr.Substring(0, imagStr.Length - 1);
+                if (token == null)
-                        imag = double.Parse(imagStr, formatProvider);
+                {
-                    }
+                    return negative ? -1 : 1;
                 }
-                else
+            }
+
+            double value = GlobalizationHelper.ParseDouble(ref token, format.GetCultureInfo());
+
+            // handle suffix imaginary symbol
+            if (token != null && String.Compare(token.Value, "i", StringComparison.OrdinalIgnoreCase) == 0)
+            {
+                if (imaginary)
                 {
+                    // only one time allowed: either prefix or suffix, or neither.
                     throw new FormatException();
                 }
+
+                imaginary = true;
+                token = token.Next;
             }
 
-            return new Complex(real, imag);
+            return negative ? -value : value;
         }
 
         /// <summary>
@@ -1226,4 +1286,4 @@ namespace MathNet.Numerics
 
         #endregion
     }
-}
+}

src/UnitTests/ComplexTests/ComplexTest.cs

@@ -1,8 +1,34 @@
-namespace MathNet.Numerics.UnitTests
+// <copyright file="ComplexTest.cs" company="Math.NET">
+// Math.NET Numerics, part of the Math.NET Project
+// http://mathnet.opensourcedotnet.info
+//
+// Copyright (c) 2009 Math.NET
+//
+// Permission is hereby granted, free of charge, to any person
+// obtaining a copy of this software and associated documentation
+// files (the "Software"), to deal in the Software without
+// restriction, including without limitation the rights to use,
+// copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following
+// conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+// OTHER DEALINGS IN THE SOFTWARE.
+// </copyright>
+
+namespace MathNet.Numerics.UnitTests.ComplexTests
 {
     using System;
-    using System.Globalization;
-
     using MbUnit.Framework;
 
     [TestFixture]
@@ -129,8 +155,7 @@
             AssertHelpers.AlmostEqual(new Complex(double.PositiveInfinity, double.PositiveInfinity), a.Power(b), 15);
             a = new Complex(0.0, 0.0);
             b = new Complex(0.0, 1.0);
-            AssertEx.That(()=>a.Power(b).IsNaN);
+            AssertEx.That(() => a.Power(b).IsNaN);
-           	
         }
 
         [Test]
@@ -200,18 +225,6 @@
             AssertHelpers.AlmostEqual(Complex.Zero, complex.SquareRoot(), 15);
         }
 
-        [Test]
-        [Row(1, -2, "1 -2i")]
-        [Row(1, 2, "1 + 2i")]
-        [Row(1, 0, "1")]
-        [Row(0, -2, "-2i")]
-        [Row(0, 2, "2i")]
-        public void CanConvertComplexToString(double real, double imag, string expected)
-        {
-            var a = new Complex(real, imag);
-            Assert.AreEqual(expected, a.ToString());
-        }
-
         [Test]
         [MultipleAsserts]
         public void CanConvertDoubleToComplex()
@@ -221,68 +234,6 @@
             Assert.AreEqual(1.1, new Complex(1.1, 0));
         }
 
-        [Test]
-        [Row("-1", -1, 0)]
-        [Row("-i", 0, -1)]
-        [Row("i", 0, 1)]
-        [Row("2i", 0, 2)]
-        [Row("1 + 2i", 1, 2)]
-        [Row("1+2i", 1, 2)]
-        [Row("1 - 2i", 1, -2)]
-        [Row("1-2i", 1, -2)]
-        [Row("1,2", 1, 2)]
-        [Row("1 , 2", 1, 2)]
-        [Row("1,2i", 1, 2)]
-        [Row("-1, -2i", -1, -2)]
-        [Row("(+1,2i)", 1, 2)]
-        [Row("(-1 , -2)", -1, -2)]
-        [Row("(-1 , -2i)", -1, -2)]
-        [Row("(+1e1 , -2e-2i)", 10, -0.02)]
-        [Row("(-1E1 -2e2i)", -10, -200)]
-        [Row("(-1e+1 -2e2i)", -10, -200)]
-        [Row("(-1e1 -2e+2i)", -10, -200)]
-        [Row("(-1e-1  -2E2i)", -0.1, -200)]
-        [Row("(-1e1  -2e-2i)", -10, -0.02)]
-        [Row("(-1E+1 -2e+2i)", -10, -200)]
-        [Row("(-1e-1,-2e-2i)", -0.1, -0.02)]
-        [Row("(+1 +2i)", 1, 2)]
-        public void CanConvertStringToComplexUsingTryParse(string str, double expectedReal, double expectedImag)
-        {
-            Complex z;
-            var ret = Complex.TryParse(str, out z);
-            Assert.IsTrue(ret);
-            Assert.AreEqual(expectedReal, z.Real);
-            Assert.AreEqual(expectedImag, z.Imaginary);
-
-            ret = Complex.TryParse("(-1E+1 -2e+2i)", out z);
-            Assert.IsTrue(ret);
-            Assert.AreEqual(-10, z.Real);
-            Assert.AreEqual(-200, z.Imaginary);
-
-            ret = Complex.TryParse("(-1e-1,-2e-2i)", out z);
-            Assert.IsTrue(ret);
-            Assert.AreEqual(-.1, z.Real);
-            Assert.AreEqual(-.02, z.Imaginary);
-
-            ret = Complex.TryParse("(+1 +2i)", out z);
-            Assert.IsTrue(ret);
-            Assert.AreEqual(1, z.Real);
-            Assert.AreEqual(2, z.Imaginary);
-        }
-
-        [Test]
-        public void CanParseStringToComplex()
-        {
-            var actual = Complex.Parse("-1 -2i");
-            Assert.AreEqual(new Complex(-1,-2), actual);
-        }
-
-        [Test]
-        public void ParseThrowsFormatExceptionIfMissingClosingParen()
-        {
-            Assert.Throws<FormatException>(() => Complex.Parse("(1,2"));
-        }
-
         [Test]
         [MultipleAsserts]
         public void CanCreateComplexNumberUsingTheConstructor()
@@ -310,43 +261,6 @@
             Assert.AreEqual(-2.2, complex.Imaginary, "Imaginary part is -2.2.");
         }
 
-        [Test]
-        [MultipleAsserts]
-        public void CanCreateStringFromComplexNumber()
-        {
-            Assert.AreEqual("NaN", Complex.NaN.ToString());
-            Assert.AreEqual("Infinity", Complex.Infinity.ToString());
-            Assert.AreEqual("1.1", new Complex(1.1, 0).ToString());
-            Assert.AreEqual("-1.1i", new Complex(0, -1.1).ToString());
-            Assert.AreEqual("1.1i", new Complex(0, 1.1).ToString());
-            Assert.AreEqual("1.1 + 1.1i", new Complex(1.1, 1.1).ToString());
-        }
-
-        [Test]
-        [MultipleAsserts]
-        public void CanCreateStringUsingFormatProvider()
-        {
-            var provider = CultureInfo.GetCultureInfo("tr-TR");
-            Assert.AreEqual("NaN", Complex.NaN.ToString(provider));
-            Assert.AreEqual("Infinity", Complex.Infinity.ToString(provider));
-            Assert.AreEqual("1,1", new Complex(1.1, 0).ToString(provider));
-            Assert.AreEqual("-1,1i", new Complex(0, -1.1).ToString(provider));
-            Assert.AreEqual("1,1i", new Complex(0, 1.1).ToString(provider));
-            Assert.AreEqual("1,1 + 1,1i", new Complex(1.1, 1.1).ToString(provider));
-        }
-
-        [Test]
-        [MultipleAsserts]
-        public void CanCreateStringUsingNumberFormat()
-        {
-            Assert.AreEqual("NaN", Complex.NaN.ToString("#.000"));
-            Assert.AreEqual("Infinity", Complex.Infinity.ToString("#.000"));
-            Assert.AreEqual("1.100", new Complex(1.1, 0).ToString("#.000"));
-            Assert.AreEqual("-1.100i", new Complex(0, -1.1).ToString("#.000"));
-            Assert.AreEqual("1.100i", new Complex(0, 1.1).ToString("#.000"));
-            Assert.AreEqual("1.100 + 1.100i", new Complex(1.1, 1.1).ToString("#.000"));
-        }
-
         [Test]
         public void CanDetermineIfImaginaryUnit()
         {
@@ -532,51 +446,6 @@
             Assert.AreEqual(complex, +complex);
         }
 
-        [Test]
-        public void TryParseCanHandleSymbols()
-        {
-            Complex z;
-            var ni = new NumberFormatInfo();
-            var ret = Complex.TryParse(ni.NegativeInfinitySymbol + "," + ni.PositiveInfinitySymbol, out z);
-            Assert.IsTrue(ret);
-            Assert.AreEqual(double.NegativeInfinity, z.Real);
-            Assert.AreEqual(double.PositiveInfinity, z.Imaginary);
-
-            ret = Complex.TryParse(ni.NaNSymbol + "," + ni.NaNSymbol, out z);
-            Assert.IsTrue(ret);
-            Assert.AreEqual(double.NaN, z.Real);
-            Assert.AreEqual(double.NaN, z.Imaginary);
-
-            ret = Complex.TryParse(ni.NegativeInfinitySymbol + "+" + ni.PositiveInfinitySymbol + "i", out z);
-            Assert.IsTrue(ret);
-            Assert.AreEqual(double.NegativeInfinity, z.Real);
-            Assert.AreEqual(double.PositiveInfinity, z.Imaginary);
-
-            ret = Complex.TryParse(ni.NaNSymbol + "+" + ni.NaNSymbol + "i", out z);
-            Assert.IsTrue(ret);
-            Assert.AreEqual(double.NaN, z.Real);
-            Assert.AreEqual(double.NaN, z.Imaginary);
-
-            ret = Complex.TryParse(double.MaxValue.ToString("R") + " " + double.MinValue.ToString("R") + "i", out z);
-            Assert.IsTrue(ret);
-            Assert.AreEqual(double.MaxValue, z.Real);
-            Assert.AreEqual(double.MinValue, z.Imaginary);
-        }
-
-        [Test]
-        [Row("")]
-        [Row("+")]
-        [Row("1i+2")]
-        [Row(null)]
-        public void TryParseReturnsFalseWhenGiveBadValue(string str)
-        {
-            Complex z;
-            var ret = Complex.TryParse(str, out z);
-            Assert.IsFalse(ret);
-            Assert.AreEqual(0, z.Real);
-            Assert.AreEqual(0, z.Imaginary);
-        }
-
         [Test]
         public void WithModulusArgumentThrowsArgumentOutOfRangeException()
         {

src/UnitTests/ComplexTests/ComplexTextHandlingTest.cs

@@ -0,0 +1,282 @@
+// <copyright file="ComplexGlobalizedTextTest.cs" company="Math.NET">
+// Math.NET Numerics, part of the Math.NET Project
+// http://mathnet.opensourcedotnet.info
+//
+// Copyright (c) 2009 Math.NET
+//
+// Permission is hereby granted, free of charge, to any person
+// obtaining a copy of this software and associated documentation
+// files (the "Software"), to deal in the Software without
+// restriction, including without limitation the rights to use,
+// copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following
+// conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+// OTHER DEALINGS IN THE SOFTWARE.
+// </copyright>
+
+namespace MathNet.Numerics.UnitTests.ComplexTests
+{
+    using System;
+    using System.Globalization;
+    using MbUnit.Framework;
+
+    [TestFixture]
+    public class ComplexTextHandlingTest
+    {
+        [Test]
+        [Row(1, -2, "1 -2i")]
+        [Row(1, 2, "1 + 2i")]
+        [Row(1, 0, "1")]
+        [Row(0, -2, "-2i")]
+        [Row(0, 2, "2i")]
+        [Row(0, 2, "2i")]
+        [Row(0, 0, "0")]
+        [Row(Double.NaN, Double.NaN, "{1}")]
+        [Row(Double.NaN, 0, "{1}")]
+        [Row(0, Double.NaN, "{1}")]
+        [Row(Double.PositiveInfinity, Double.PositiveInfinity, "{2}")]
+        [Row(1.1, 0, "1{0}1")]
+        [Row(-1.1, 0, "-1{0}1")]
+        [Row(0, 1.1, "1{0}1i")]
+        [Row(0, -1.1, "-1{0}1i")]
+        [Row(1.1, 1.1, "1{0}1 + 1{0}1i")]
+        public void CanFormatComplexToString(double real, double imag, string expected)
+        {
+            var numberFormat = NumberFormatInfo.CurrentInfo;
+            var a = new Complex(real, imag);
+            Assert.AreEqual(
+                String.Format(
+                    expected,
+                    numberFormat.NumberDecimalSeparator,
+                    numberFormat.NaNSymbol,
+                    numberFormat.PositiveInfinitySymbol),
+                a.ToString());
+        }
+
+        [Test]
+        [MultipleAsserts]
+        [Row("en-US", "NaN", "Infinity", "1.1")]
+        [Row("tr-TR", "NaN", "Infinity", "1,1")]
+        [Row("de-DE", "n. def.", "+unendlich", "1,1")]
+        [Row("de-CH", "n. def.", "+unendlich", "1.1")]
+        [Row("he-IL", "לא מספר", "אינסוף חיובי", "1.1")]
+        public void CanFormatComplexToStringWithCulture(
+            string cultureName, string nan, string infinity, string number)
+        {
+            var provider = CultureInfo.GetCultureInfo(cultureName);
+            Assert.AreEqual(nan, Complex.NaN.ToString(provider));
+            Assert.AreEqual(infinity, Complex.Infinity.ToString(provider));
+            Assert.AreEqual("0", Complex.Zero.ToString(provider));
+            Assert.AreEqual(String.Format("{0}", number), new Complex(1.1, 0).ToString(provider));
+            Assert.AreEqual(String.Format("-{0}", number), new Complex(-1.1, 0).ToString(provider));
+            Assert.AreEqual(String.Format("-{0}i", number), new Complex(0, -1.1).ToString(provider));
+            Assert.AreEqual(String.Format("{0}i", number), new Complex(0, 1.1).ToString(provider));
+            Assert.AreEqual(String.Format("{0} + {0}i", number), new Complex(1.1, 1.1).ToString(provider));
+        }
+
+        [Test]
+        [MultipleAsserts]
+        public void CanFormatComplexToStringWithFormat()
+        {
+            Assert.AreEqual("0", String.Format("{0:G}", Complex.Zero));
+            Assert.AreEqual("1 + 2i", String.Format("{0:G}", new Complex(1, 2)));
+            Assert.AreEqual("001 + 002i", String.Format("{0:000;minus 000;zero}", new Complex(1, 2)));
+            Assert.AreEqual("minus 002i", String.Format("{0:000;minus 000;zero}", new Complex(0, -2)));
+            Assert.AreEqual("zero", String.Format("{0:000;minus 000;zero}", Complex.Zero));
+
+            Assert.AreEqual("0", Complex.Zero.ToString("G"));
+            Assert.AreEqual("1 + 2i", new Complex(1, 2).ToString("G"));
+            Assert.AreEqual("001 + 002i", new Complex(1, 2).ToString("#000;minus 000;zero"));
+            Assert.AreEqual("minus 002i", new Complex(0, -2).ToString("#000;minus 000;zero"));
+            Assert.AreEqual("zero", Complex.Zero.ToString("#000;minus 000;zero"));
+        }
+
+        [Test]
+        [MultipleAsserts]
+        public void CanFormatComplexToStringWithFormatInvariant()
+        {
+            var culture = CultureInfo.InvariantCulture;
+
+            Assert.AreEqual("NaN", String.Format(culture, "{0:.000}", Complex.NaN));
+            Assert.AreEqual(".000", String.Format(culture, "{0:.000}", Complex.Zero));
+            Assert.AreEqual("1.100", String.Format(culture, "{0:.000}", new Complex(1.1, 0)));
+            Assert.AreEqual("1.100 + 1.100i", String.Format(culture, "{0:.000}", new Complex(1.1, 1.1)));
+
+            Assert.AreEqual("NaN", Complex.NaN.ToString("#.000", culture));
+            Assert.AreEqual("Infinity", Complex.Infinity.ToString("#.000", culture));
+            Assert.AreEqual(".000", Complex.Zero.ToString("#.000", culture));
+            Assert.AreEqual("1.100", new Complex(1.1, 0).ToString("#.000", culture));
+            Assert.AreEqual("-1.100i", new Complex(0, -1.1).ToString("#.000", culture));
+            Assert.AreEqual("1.100i", new Complex(0, 1.1).ToString("#.000", culture));
+            Assert.AreEqual("1.100 + 1.100i", new Complex(1.1, 1.1).ToString("#.000", culture));
+        }
+
+        [Test]
+        [Row("-1 -2i", -1, -2, "en-US")]
+        [Row("-1 - 2i ", -1, -2, "de-CH")]
+        public void CanParseStringToComplexWithCulture(
+            string text, double expectedReal, double expectedImaginary, string cultureName)
+        {
+            Complex parsed = Complex.Parse(text, CultureInfo.GetCultureInfo(cultureName));
+            Assert.AreEqual(expectedReal, parsed.Real);
+            Assert.AreEqual(expectedImaginary, parsed.Imaginary);
+        }
+
+        [Test]
+        [Row("1", 1, 0)]
+        [Row("-1", -1, 0)]
+        [Row("-i", 0, -1)]
+        [Row("i", 0, 1)]
+        [Row("2i", 0, 2)]
+        [Row("1 + 2i", 1, 2)]
+        [Row("1+2i", 1, 2)]
+        [Row("1 - 2i", 1, -2)]
+        [Row("1-2i", 1, -2)]
+        [Row("1,2 ", 1, 2)]
+        [Row("1 , 2", 1, 2)]
+        [Row("1,2i", 1, 2)]
+        [Row("-1, -2i", -1, -2)]
+        [Row(" - 1 , - 2 i ", -1, -2)]
+        [Row("(+1,2i)", 1, 2)]
+        [Row("(-1 , -2)", -1, -2)]
+        [Row("(-1 , -2i)", -1, -2)]
+        [Row("(+1e1 , -2e-2i)", 10, -0.02)]
+        [Row("(-1E1 -2e2i)", -10, -200)]
+        [Row("(-1e+1 -2e2i)", -10, -200)]
+        [Row("(-1e1 -2e+2i)", -10, -200)]
+        [Row("(-1e-1  -2E2i)", -0.1, -200)]
+        [Row("(-1e1  -2e-2i)", -10, -0.02)]
+        [Row("(-1E+1 -2e+2i)", -10, -200)]
+        [Row("(-1e-1,-2e-2i)", -0.1, -0.02)]
+        [Row("(+1 +2i)", 1, 2)]
+        [Row("(-1E+1 -2e+2i)", -10, -200)]
+        [Row("(-1e-1,-2e-2i)", -0.1, -0.02)]
+        public void CanTryParseStringToComplexWithInvariant(string str, double expectedReal, double expectedImaginary)
+        {
+            var invariantCulture = CultureInfo.InvariantCulture;
+            Complex z;
+            var ret = Complex.TryParse(str, invariantCulture, out z);
+            Assert.IsTrue(ret);
+            Assert.AreEqual(expectedReal, z.Real);
+            Assert.AreEqual(expectedImaginary, z.Imaginary);
+        }
+
+        [Test]
+        public void ParseThrowsFormatExceptionIfMissingClosingParen()
+        {
+            Assert.Throws<FormatException>(() => Complex.Parse("(1,2"));
+        }
+
+        [Test]
+        public void TryParseCanHandleSymbols()
+        {
+            Complex z;
+            var ni = NumberFormatInfo.CurrentInfo;
+            var separator = CultureInfo.CurrentCulture.TextInfo.ListSeparator;
+            var ret = Complex.TryParse(
+                ni.NegativeInfinitySymbol + separator + ni.PositiveInfinitySymbol, out z);
+            Assert.IsTrue(ret, "A1");
+            Assert.AreEqual(double.NegativeInfinity, z.Real, "A2");
+            Assert.AreEqual(double.PositiveInfinity, z.Imaginary, "A3");
+
+            ret = Complex.TryParse(ni.NaNSymbol + separator + ni.NaNSymbol, out z);
+            Assert.IsTrue(ret, "B1");
+            Assert.AreEqual(double.NaN, z.Real, "B2");
+            Assert.AreEqual(double.NaN, z.Imaginary, "B3");
+
+            ret = Complex.TryParse(ni.NegativeInfinitySymbol + "+" + ni.PositiveInfinitySymbol + "i", out z);
+            Assert.IsTrue(ret, "C1");
+            Assert.AreEqual(double.NegativeInfinity, z.Real, "C2");
+            Assert.AreEqual(double.PositiveInfinity, z.Imaginary, "C3");
+
+            ret = Complex.TryParse(ni.NaNSymbol + "+" + ni.NaNSymbol + "i", out z);
+            Assert.IsTrue(ret, "D1");
+            Assert.AreEqual(double.NaN, z.Real, "D2");
+            Assert.AreEqual(double.NaN, z.Imaginary, "D3");
+
+            ret = Complex.TryParse(
+                double.MaxValue.ToString("R") + " " + double.MinValue.ToString("R") + "i",
+                out z);
+            Assert.IsTrue(ret, "E1");
+            Assert.AreEqual(double.MaxValue, z.Real, "E2");
+            Assert.AreEqual(double.MinValue, z.Imaginary, "E3");
+        }
+
+        [Test]
+        [Row("en-US")]
+        [Row("tr-TR")]
+        [Row("de-DE")]
+        [Row("de-CH")]
+        [Row("he-IL")]
+        public void TryParseCanHandleSymbolsWithCulture(string cultureName)
+        {
+            Complex z;
+            var culture = CultureInfo.GetCultureInfo(cultureName);
+            var ni = culture.NumberFormat;
+            var separator = culture.TextInfo.ListSeparator;
+            var ret = Complex.TryParse(
+                ni.NegativeInfinitySymbol + separator + ni.PositiveInfinitySymbol, culture, out z);
+            Assert.IsTrue(ret, "A1");
+            Assert.AreEqual(double.NegativeInfinity, z.Real, "A2");
+            Assert.AreEqual(double.PositiveInfinity, z.Imaginary, "A3");
+
+            ret = Complex.TryParse(ni.NaNSymbol + separator + ni.NaNSymbol, culture, out z);
+            Assert.IsTrue(ret, "B1");
+            Assert.AreEqual(double.NaN, z.Real, "B2");
+            Assert.AreEqual(double.NaN, z.Imaginary, "B3");
+
+            ret = Complex.TryParse(ni.NegativeInfinitySymbol + "+" + ni.PositiveInfinitySymbol + "i", culture, out z);
+            Assert.IsTrue(ret, "C1");
+            Assert.AreEqual(double.NegativeInfinity, z.Real, "C2");
+            Assert.AreEqual(double.PositiveInfinity, z.Imaginary, "C3");
+
+            ret = Complex.TryParse(ni.NaNSymbol + "+" + ni.NaNSymbol + "i", culture, out z);
+            Assert.IsTrue(ret, "D1");
+            Assert.AreEqual(double.NaN, z.Real, "D2");
+            Assert.AreEqual(double.NaN, z.Imaginary, "D3");
+
+            ret = Complex.TryParse(
+                double.MaxValue.ToString("R", culture) + " " + double.MinValue.ToString("R", culture) + "i",
+                culture,
+                out z);
+            Assert.IsTrue(ret, "E1");
+            Assert.AreEqual(double.MaxValue, z.Real, "E2");
+            Assert.AreEqual(double.MinValue, z.Imaginary, "E3");
+        }
+
+        [Test]
+        [Row("")]
+        [Row("+")]
+        [Row("1-")]
+        [Row("i+")]
+        [Row("1/2i")]
+        [Row("1i+2i")]
+        [Row("i1i")]
+        [Row("(1i,2)")]
+        [Row("1e+")]
+        [Row("1e")]
+        [Row("1,")]
+        [Row(",1")]
+        [Row(null)]
+        public void TryParseReturnsFalseWhenGiveBadValueWithInvariant(string str)
+        {
+            Complex z;
+            var ret = Complex.TryParse(str, CultureInfo.InvariantCulture, out z);
+            Assert.IsFalse(ret);
+            Assert.AreEqual(0, z.Real);
+            Assert.AreEqual(0, z.Imaginary);
+        }
+    }
+}

src/UnitTests/UnitTests.csproj

@@ -62,6 +62,7 @@
     <Compile Include="ArgumentCheckContract.cs" />
     <Compile Include="AssertHelpers.cs" />
     <Compile Include="CombinatoricsTests\CombinatoricsCountingTest.cs" />
+    <Compile Include="ComplexTests\ComplexTextHandlingTest.cs" />
     <Compile Include="ComplexTests\ComplexTest.cs" />
     <Compile Include="DistributionTests\CommonDistributionTests.cs" />
     <Compile Include="DistributionTests\Continuous\BetaTests.cs" />