C#'s LINQ (query syntax, not methods) got it right
var result = from s in stringList where s.Contains("Tutorials") select s;
var result = from s in stringList where s.Contains("Tutorials") select s;
Linq query syntax is just dumb
I can't stand the non-extension-method Linq syntax: the _only_ place where it offers a readability improvement over ext-methods is using `join` - but I hardly ever do that in Linq anyway.
Also, in both my code and yours, `result` will be a lazy-evaluated `IEnumerable<String>` which may be undesirable - which means it's probably a good idea to use `.ToList()` to materialize it - which means having to use ext-methods anyway - and mixing both syntaxes in the same expression is aesthetically atrocious.
Hah! I tell the juniors this all the time :D. This seems to be basically the consensus among the C# community these days as far as I can tell as well.
Read: "you create new heap-allocated closures which wreck your Linq expression's runtime performance"
Or:
"you create Linq queries that cannot be translated into SQL"
——
On a related note, it’s interesting just how unpopular so many new C# language features are (just by looking at the numbers of Thumbs-down reactions on the GitHub Issues/PRs - stuff like top-level Main. It feels like C#’s LDT wants to be like Swift, but without Swift’s willingness to ditch ill-conceived features after a few years… but I think C# would be well-served by taking an axe to some language-features by now - like keyword-Linq and CLS-compliance (honestly, do any ISAs today still lack hardware support for unsigned ints?)
I think there are some otherwise-seldom-used linq overloads for doing just that. Maybe on Join() or GroupJoin() or something like that. Query expressions use them for compilation to keep closure use down, but I don't know too much about it.
Anyway, if top-level statements are wrong, I don't ever want to be right. I had no idea there was any controversy on that. It's trivial to add the boiler-plate back in if you want it.
The main thing that bugs me is that Expression<> is stuck with language features that existed in C#4, even when there are trivial lowerings. e.g. `is not null` could be `!= null`. (This example ignores operator implementations, but most IQueryables ignore more than that already) Even better, add AST node types for the new language features.
Top level statements and the new HostBuilders are fantastic, they're much cleaner and easier to follow than the previous mess. Add Minimal APIs to the mix and C# is finally a viable choice for spinning up something quickly.
No love for let?
from item in items
let frob = Expenseive(item.P1)
where frob > 3
selec new { frob, item }...and ValueTuples are superior to Anonymous Types because you can actually return them from a function or use them as parameters - whereas Anonymous Types cannot cross method-call boundaries (excepting using generics for pass-through).
Anonymous Types in C# were a massive mistake. They should be [Obsolete]'d, IMO.
I've been just showing that *approach* of starting SQL query from "from" part is viable, because that's how Microsoft timplemented in one of two LINQ "API"s"
I'm not trying to convince anyone to use LINQ's Query Syntax.
Linq is a (reasonably) compromised, non-referentially-transparent, implementation of a restricted form of relational-algebra with side-effects permitted, so I'm not comfortable describing Linq as "monadic".
Whereas Haskell's `do` is strictly monadic.