private static IAppendableExpr ZipOn(IExpr[] outerKeys, IExpr[] innerKeys)
{
if (outerKeys.Length != innerKeys.Length)
{
throw new Exception("Inner and Outer key selectors must specify the same number of keys");
}
IAppendableExpr on = Expr.Empty;
for (int n = 0; n < outerKeys.Length && n < innerKeys.Length; n++)
{
on = on.And(Expr.Eq(outerKeys[n], innerKeys[n]));
}
return(on);
}
internal static IExpr IdentityExpr <T>(T value)
{
var reflection = StencilContext.ReflectionServices;
if (reflection == null)
{
throw new MissingReflectionException();
}
var metadata = EnsureMetadata(typeof(T));
IAppendableExpr result = Expr.Empty;
foreach (var item in metadata.Keys)
{
var keyName = (Variable)item.Key;
var keyValue = new Literal(reflection.GetValue(item, value));
result = result.And(Expr.Eq(keyName, keyValue));
}
return(result);
}