public static LambdaExpression Rebind(BoundExpression expression)
{
var rebinder = new RebindToScope {
BlockCount = expression.BlockNumber
};
return(rebinder.Rebind(expression.Expression));
}
/// <summary>
/// Converts a single bind expression to the Haxl monad.
/// </summary>
/// <param name="bind"></param>
/// <returns></returns>
public static Func <Scope, Haxl> BindToHaxl(BindStatement bind)
{
return(scope =>
{
var rewritten = RebindToScope.Rebind(bind.Expression);
var value = rewritten.Compile().DynamicInvoke(scope);
var wrapped = (Fetchable)value;
return wrapped.ToHaxlFetch(bind.Expression.BindVariable, scope);
});
}
/// <summary>
/// Converts a project expression to Haxl monad.
/// </summary>
public static Func <Scope, Haxl> ProjectToHaxl(ProjectStatement project, string parentBind)
{
return(scope => Haxl.FromFunc((cache, logger) =>
{
var rewritten = RebindToScope.Rebind(project.Expression);
var result = rewritten.Compile().DynamicInvoke(scope);
return Done.New(_ =>
{
if (project.Expression.BindVariable == HAXL_RESULT_NAME &&
!scope.IsRoot &&
parentBind != null)
{
return scope.WriteParent(parentBind, result);
}
return scope.Add(project.Expression.BindVariable, result);
});
}));
}