C#'s greatest mistakes

[Roman Ivanov]

On 11/27/2010 5:32 PM, BLS wrote:
> On 27/11/2010 23:16, spir wrote:
>> Maybe the example does not show what you actually mean, but I do not
>> see any advantage. Version plain D is close to perfect, obvious,
>> direct; version embedded DSL just adds noise (and work for
>> implementing the feature, and work for a precompiler or whatever...).
> 
> 1-How do you implement LINQ in D ?

AFAIK, LINQ is _not_ SQL embedded into C# or VB. It's a mechanism that
allows C# to examine expressions (written in C#, as strange as they
might look) and translate them to SQL (or whatever).

LINQ can take two forms.

First:
var query = from s in names
 where s.Length == 5
 orderby s
 select s.ToUpper();

Second:
var query = names.where(s => s.Length == 5)
 .orderby(s => s)
 .select(s => s.ToUpper());

They are semantically identical, but I like the second syntax much more,
because it uses existing language features, works with auto-completion
and is much more readable in complex cases.

To support something like that a language needs to have tools for
introspection of its own code.

> 2-Having such an compiler plugin architecture, will enable you f.i to
> seamless use Go, Lisp whatever  within  D.
> 
> 3-Even if these plugins (please note > more than one) are just for SQL,
> you got database access for free.

LINQ for databases is a bit overrated. Writing real SQL queries is often
simpler. LINQ query generator does some optimizations, but it also
screws up in some cases. LINQ to objects is a different story, because
it allows for much nicer declarative syntax to do mapping and projections.

> 4- I am using such an EBNF driven tool (almost written by me) to
> translate SQL scripts. // Create a new db from firebird to mssql..
> including stored procedures, triggers etc.
> 
> So sorry Denis, I know what I am talking about.
> Bjoern