Block expressions, a way to group statements into an expression

[remorses]

In Python there is no way to handle an error in an expression, this is also the case for match and non inline if statements. This becomes a problem when you want to assign a variable directly with the result of an if, try or match statement.

Mojo could add a way to create an expression out of a group of statements.

Zig has something similar and Rust too, but usually you don't need them because most things in Rust are expressions and not statements.

# with without anything becomes a way to turn a block into an expression
var result = with:
    try:
        something()
        break "success"
    except ValueError:
        break "ValueError"
    except IndexError:
        break "IndexError"


# same code without this feature
var result: String
try:
    something()
    result = "success"
except ValueError:
    result = "ValueError"
except IndexError:
    result = "IndexError"

Same thing in Rust:

let result = match something() {
    Ok(_) => "success".to_string(),
    Err(e) => match e {
        "ValueError" | "IndexError" => "".to_string(),
        _ => "other error".to_string(),
    },
};