Added: LDM Notes for Jan. 15, 2020 and Jan. 22, 2020

[agocke]

Jan 22, 2020

https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-01-22.md

1. Top-level statements and functions
2. Expression Blocks

Jan 15, 2020

https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-01-15.md

Records

1. "programming with data"
2. Decomposing subfeatures of records

[orthoxerox]

Were nondestructive mutation and data-friendly defaults not discussed during the meeting or are the notes from Jan 15 incomplete?

[qrli]

The most notable restrictions are that you cannot branch out, meaning that return, yield break, and yield return, and goto would be illegal in this proposal.

Does it mean break; is legal? E.g.

while (true) {
    Foo({ break; 2 });
}

If that's true, we can have something like below?

while (true) {
    Foo({ break 2; });
    Foo({ break; 2 });
}

[qrli]

Object initializers
...
On the other hand, this also removes one of the main benefits for having a constructor, namely that you can validate the whole state of the object before producing it.

Not if object initializer calls an optional method (e.g. void OnConstructed()) to do what can be done in a constructor. Similar to what deserializers do after deserialization, that the [OnDeserialized] attribute marks a method to be the callback. Maybe it is worth to have that pattern supported by the language itself?

[agocke]

@orthoxerox They weren't discussed until later, see https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-01-29.md