/// <summary>
/// C# 3.0 增加了 lambda，所以可以使用 lambda 表达式优化匿名函数
/// </summary>
public static void LambdaExpressions()
{
ComparisonTest tester = (first, second) => first.Length == second.Length;
Console.WriteLine($"anonymous methods returned: {tester("Hello", "World")}");
var cities = new[] { "London", "Madrid" };
var friends = new[] { "Minnie", "Goofey" };
Console.WriteLine($"Are friends and cities similar? {AreSimilar(cities, friends, tester)}"); // 使用匿名方法实现的委托
}
static bool AreSimilar(string[] leftItems, string[] rightItems, ComparisonTest tester)
{
if (leftItems.Length != rightItems.Length)
return false;
for (int i = 0; i < leftItems.Length; i++)
{
if (tester(leftItems[i], rightItems[i]) == false)
{
return false;
}
}
return true;
}
/// <summary>
/// Creates a new basic generic operations implementation using the given expression generator.
/// </summary>
/// <param name="expressionGenerator">The expression generator that will be used to build the generic methods at run-time.</param>
public BasicOperations(IExpressionGenerator expressionGenerator)
{
if (null == expressionGenerator)
{
throw new ArgumentNullException("expressionGenerator");
}
Contract.EndContractBlock();
ExpressionGenerator = expressionGenerator;
Add = BuildBinaryFunc("Add");
Subtract = BuildBinaryFunc("Subtract");
Multiply = BuildBinaryFunc("Multiply");
Divide = BuildBinaryFunc("Divide");
Negate = BuildUnaryFunc("Negate");
Sin = BuildUnaryFunc("Sin");
Cos = BuildUnaryFunc("Cos");
Tan = BuildUnaryFunc("Tan");
Asin = BuildUnaryFunc("Asin");
Acos = BuildUnaryFunc("Acos");
Atan = BuildUnaryFunc("Atan");
Sinh = BuildUnaryFunc("Sinh");
Cosh = BuildUnaryFunc("Cosh");
Tanh = BuildUnaryFunc("Tanh");
Asinh = BuildUnaryFunc("Asinh");
Acosh = BuildUnaryFunc("Acosh");
Atanh = BuildUnaryFunc("Atanh");
Log = BuildUnaryFunc("Log");
Log10 = BuildUnaryFunc("Log10");
Exp = BuildUnaryFunc("Exp");
Abs = BuildUnaryFunc("Abs");
Atan2 = BuildBinaryFunc <ReverseCoordinates, TValue>("Atan2");
Pow = BuildBinaryFunc("Pow");
Ceiling = BuildUnaryFunc("Ceiling");
Floor = BuildUnaryFunc("Floor");
Truncate = BuildUnaryFunc("Truncate");
Min = BuildBinaryFunc("Min");
Max = BuildBinaryFunc("Max");
Equal = BuildBinaryFunc <ComparisonTest, bool>("Equal");
NotEqual = BuildBinaryFunc <ComparisonTest, bool>("NotEqual");
Less = BuildBinaryFunc <ComparisonTest, bool>("Less");
LessOrEqual = BuildBinaryFunc <ComparisonTest, bool>("LessEqual");
Greater = BuildBinaryFunc <ComparisonTest, bool>("Greater");
GreaterOrEqual = BuildBinaryFunc <ComparisonTest, bool>("GreaterOrEqual");
CompareTo = BuildBinaryFunc <Comparison <TValue>, int>("CompareTo");
ToDouble = BuildConversion <TValue, double>();
FromDouble = BuildConversion <double, TValue>();
_zeroValueGenerator = BuildConstant("0");
}
private static void AnonymousMethod()
{
string[] cities = new[] { "London", "Madrid", "TelAviv" };
string[] friends = new[] { "Minnie", "Goofey", "MickeyM" };
//Anonymous Method
ComparisonTest lengthComparer = delegate(string first, string second)
{
return(first.Length == second.Length);
};
Console.WriteLine("anonymous method returned: {0}", lengthComparer("Hello", "World"));
PassingAnonymousMethodAsArgument(cities, friends);
}
public delegate bool ComparisonTest(string first, string second); // 使用 delegate 定义委托
/// <summary>
/// 直接使用 delegate 关键字来实现委托有一点不好，就是得写一个有命名的方法，有点割裂感
/// 所以这里使用匿名方法来优化这个步骤
/// </summary>
public static void AnonymousMethods()
{
ComparisonTest tester = delegate(string first, string second)
{
return(first.Length == second.Length);
};
Console.WriteLine($"anonymous methods returned: {tester("Hello", "World")}");
var cities = new[] { "London", "Madrid" };
var friends = new[] { "Minnie", "Goofey" };
Console.WriteLine($"Are friends and cities similar? {AreSimilar(cities, friends, tester)}"); // 使用匿名方法实现的委托
}
private static void UsingDelegates()
{
string s1 = "Hello";
string s2 = "World";
var comparators = new StringComparators();
ComparisonTest test = new ComparisonTest(comparators.CompareContent);
Console.WriteLine("CompareContent returned: {0}", test(s1, s2));
test = new ComparisonTest(StringComparators.CompareLength);
Console.WriteLine("CompareLength returned: {0}", test(s1, s2));
ComparisonTest test2 = comparators.CompareContent;
}
public void ExpressionTestCasesForTranslatedBcl(object[] parameters)
{
Func <Configuration> makeConfiguration = () =>
{
var c = ComparisonTest.MakeDefaultConfiguration();
c.Assemblies.TranslateAdditional.Add(Path.Combine(ComparisonTest.JSILFolder, "JSIL.ExpressionInterpreter.dll"));
return(c);
};
RunTestCase(parameters, makeConfiguration,
new[]
{
Path.GetFullPath(Path.Combine(ComparisonTest.TestSourceFolder, "..", "Libraries",
"JSIL.ExpressionInterpreter.js"))
});
}
private static bool AreSimilar(string[] leftItems, string[] rightItems, ComparisonTest tester)
{
if (leftItems.Length != rightItems.Length)
{
return(false);
}
for (int i = 0; i < leftItems.Length; i++)
{
if (tester(leftItems[i], rightItems[i]) == false)
{
return(false);
}
}
return(true);
}
private void RunTestCase(object[] parameters, Func <Configuration> makeConfiguration, IEnumerable <string> additionalFilesToLoad)
{
var bootstrapFileName = Path.Combine(
Path.GetDirectoryName(BootsrapperFileName),
GetType().Name,
ComparisonTest.MapSourceFileToTestFile(Path.GetFileName(BootsrapperFileName)));
RunSingleComparisonTestCase(
parameters,
makeConfiguration,
new JSEvaluationConfig
{
ThrowOnUnimplementedExternals = false,
AdditionalFilesToLoad =
Enumerable.Repeat(bootstrapFileName, 1)
.Concat(additionalFilesToLoad ?? Enumerable.Empty <string>())
.ToArray()
}
);
}
/// <summary>
/// 使用 delegate 关键字来实现委托
/// 委托用来表示一个方法的引用，所以可以用来实现高阶函数
/// 委托编译后其实会生成一个类
/// </summary>
public static void DelegateAsParameterType()
{
var s1 = "Hello";
var s2 = "World";
var comparators = new StringComparators();
var test = new ComparisonTest(comparators.CompareContent); // 委托传实例方法参数
Console.WriteLine($"CompareContent returned: {test(s1, s2)}");
test = new ComparisonTest(StringComparators.CompareLength); // 委托传静态方法参数
Console.WriteLine($"CompareLength returned: {test(s1, s2)}");
test = comparators.CompareContent; // 简化版写法
Console.WriteLine($"CompareContent returned: {test(s1, s2)}");
var cities = new[] { "London", "Madrid" };
var friends = new[] { "Minnie", "Goofey" };
test = StringComparators.CompareLength;
Console.WriteLine($"Are friends and cities similar? {AreSimilar(cities, friends, test)}"); // 使用委托实现高阶函数
}
private static Dictionary<IntPtr, string> FindWindowsByCaptionWithTest(ComparisonTest test)
{
Dictionary<IntPtr, string> mTitlesList = new Dictionary<IntPtr, string>();
Dictionary<IntPtr, string> finalList = new Dictionary<IntPtr, string>();
EnumDelegate enumfunc = (EnumDelegate)delegate(IntPtr hWnd, int lParam)
{
string title = GetWindowText(hWnd);
mTitlesList.Add(hWnd, title);
return true;
};
IntPtr hDesktop = IntPtr.Zero;
bool success = _EnumDesktopWindows(hDesktop, enumfunc, IntPtr.Zero);
if (success)
{
foreach (var KV in mTitlesList)
{
if ((bool)test(KV.Value))
{
finalList.Add(KV.Key, KV.Value);
}
}
}
return finalList;
}
private static void UsingDelegates()
{
string s1 = "Hello";
string s2 = "World";
var comperators = new StringComparators();
ComparisonTest test = new ComparisonTest(comperators.CompareContent);
Console.WriteLine("CompareContent returned: {0}", test(s1, s2));
test = new ComparisonTest(StringComparators.CompareLength);
Console.WriteLine("CompareLength returned: {0}", test(s1, s2));
ComparisonTest test2 = comperators.CompareContent;
}
private static void IntroducingLambdas()
{
ComparisonTest x = (s1, s2) => s1 == s2;
ComparisonTest y = delegate(string s1, string s2) { return(s1 == s2); };
}
