计算器编程代码(5)

object o = EvalToObject(statement); return o.ToString(); }

public static object EvalToObject(string statement) {

return

_evaluatorType.InvokeMember(\object[] { statement }); }

static Evaluator() {

ICodeCompiler compiler;

compiler = new JScriptCodeProvider().CreateCompiler();

CompilerParameters parameters; parameters = new CompilerParameters(); parameters.GenerateInMemory = true;

CompilerResults results; results _jscriptSource);

Assembly assembly = results.CompiledAssembly;

_evaluatorType = assembly.GetType(\

_evaluator = Activator.CreateInstance(_evaluatorType); }

private static object _evaluator = null; private static Type _evaluatorType = null; private static readonly string _jscriptSource = @\ Evaluator {

class Evaluator {

public function Eval(expr : String) : String

{

return eval(expr); }

=

compiler.CompileAssemblyFromSource(parameters,

} }\ }