public override RuntimeValueWrapper Execute(DoExpression e, RuntimeContext context)
{
RuntimeValueWrapper result = null;
RuntimeContext newContext = new RuntimeContext()
{
PreviousContext = context
};
foreach (Expression expression in e.Expressions)
{
VarExpression var = expression as VarExpression;
if (var == null)
{
expression.BuildContext(newContext);
result = expression.Execute(newContext);
}
else
{
result = new RuntimeValueWrapper(new RuntimeUnevaluatedValue(var.Expression), context);
if (!var.Pattern.Match(context, result))
{
throw new Exception("模式匹配不成功。");
}
}
}
if (result == null)
{
return(RuntimeValueWrapper.CreateValue(new object()));
}
else
{
return(result);
}
}
public override RuntimeValueWrapper Execute(DoExpression e, RuntimeContext context)
{
Func <RuntimeValueWrapper[], RuntimeValueWrapper> monadFunction = arguments =>
{
StatePackage result = new StatePackage()
{
result = null,
state = arguments[0]
};
RuntimeContext newContext = new RuntimeContext()
{
PreviousContext = context
};
newContext.Values.Add("return", RuntimeValueWrapper.CreateFunction(ReturnStateMonadValue, 2));
foreach (Expression expression in e.Expressions)
{
VarExpression var = expression as VarExpression;
if (var == null)
{
expression.BuildContext(newContext);
result = RunStateMonad(new RuntimeValueWrapper(new RuntimeUnevaluatedValue(expression), newContext), result.state);
}
else
{
result = RunStateMonad(new RuntimeValueWrapper(new RuntimeUnevaluatedValue(var.Expression), newContext), result.state);
if (!var.Pattern.Match(newContext, result.result))
{
throw new Exception("模式匹配不成功。");
}
}
if (!(bool)continueFunction.Invoke(result.state).RuntimeObject)
{
break;
}
}
if (result.result == null)
{
result.result = RuntimeValueWrapper.CreateValue(new object());
}
return(RuntimeValueWrapper.CreateValue(result));
};
return(RuntimeValueWrapper.CreateFunction(monadFunction, 1));
}