private void Compile(string expression, ExpressionOptions options)
{
// Add the services that will be used by elements during the compile
IServiceContainer services = new ServiceContainer();
this.AddServices(services);
// Parse and get the root element of the parse tree
ExpressionElement topElement = _myContext.Parse(expression, services);
if (options.ResultType == null)
{
options.ResultType = topElement.ResultType;
}
RootExpressionElement rootElement = new RootExpressionElement(topElement, options.ResultType);
DynamicMethod dm = this.CreateDynamicMethod();
FleeILGenerator ilg = new FleeILGenerator(dm.GetILGenerator());
// Emit the IL
rootElement.Emit(ilg, services);
if (ilg.NeedsSecondPass())
{
// second pass required due to long branches.
dm = this.CreateDynamicMethod();
ilg.PrepareSecondPass(dm.GetILGenerator());
rootElement.Emit(ilg, services);
}
ilg.ValidateLength();
// Emit to an assembly if required
if (options.EmitToAssembly == true)
{
EmitToAssembly(ilg, rootElement, services);
}
Type delegateType = typeof(ExpressionEvaluator <>).MakeGenericType(typeof(T));
_myEvaluator = (ExpressionEvaluator <T>)dm.CreateDelegate(delegateType);
}
/// <summary>
/// Emit to an assembly. We've already computed long branches at this point,
/// so we emit as a second pass
/// </summary>
/// <param name="ilg"></param>
/// <param name="rootElement"></param>
/// <param name="services"></param>
private static void EmitToAssembly(FleeILGenerator ilg, ExpressionElement rootElement, IServiceContainer services)
{
AssemblyName assemblyName = new AssemblyName(EmitAssemblyName);
string assemblyFileName = string.Format("{0}.dll", EmitAssemblyName);
AssemblyBuilder assemblyBuilder = AssemblyBuilder.DefineDynamicAssembly(assemblyName, AssemblyBuilderAccess.Run);
ModuleBuilder moduleBuilder = assemblyBuilder.DefineDynamicModule(assemblyFileName);
MethodBuilder mb = moduleBuilder.DefineGlobalMethod("Evaluate", MethodAttributes.Public | MethodAttributes.Static, typeof(T), new Type[] {
typeof(object), typeof(ExpressionContext), typeof(VariableCollection)
});
// already emitted once for local use,
ilg.PrepareSecondPass(mb.GetILGenerator());
rootElement.Emit(ilg, services);
moduleBuilder.CreateGlobalFunctions();
//assemblyBuilder.Save(assemblyFileName);
assemblyBuilder.CreateInstance(assemblyFileName);
}