trouble trying out vector iteration about cppfront HOT 6 CLOSED

The syntax for for loops in cpp2 is different. It should be rewritten to:

#include <vector>

main: () -> int = {
    v : std::vector = (1, 2, 3, 4, 5);

    i : int = 0;
    for v do :(inout item : _) = {
        if i > 3 {
            v.resize(100);
        }
        i += 1;
    }
}

(https://godbolt.org/z/d8o1bzMWc)

or using next syntax

#include <vector>

main: () -> int = {
    v : std::vector = (1, 2, 3, 4, 5);

    i : int = 0;
    for v next i++ do :(inout item : _) = {
        if i > 3 {
            v.resize(100);
        }
    }
}

When cppfront complain about braces you should check regression-tests directory for some examples of syntax. For loops please check:

• https://github.com/hsutter/cppfront/blob/main/regression-tests/pure2-intro-example-three-loops.cpp2

Please remember that in cpp2 sections you can use only cpp2 syntax.

from cppfront.

I got the syntax from a cpp2 regression test file already, I copied the last loop here: https://github.com/hsutter/cppfront/blob/main/regression-tests/mixed-intro-example-three-loops.cpp2

Why does it work there but not here?

from cppfront.

Seems like a lie. The whole file is Cpp1 syntax. If the function signature is not Cpp2 syntax, the body won't be parsed as Cpp2 syntax, AFAIK.

from cppfront.

Please learn the cpp2 syntax from files starting with pure2-. These are the files that have only cpp2 syntax.

from cppfront.

@jgarvin wrote:

I was curious to see if cpp2 improvements included iterator invalidation safety

Not yet implemented, but planned. See this project's home page README.md > 2015: Lifetime safety section, which has links to the static analysis specification (part of the C++ Core Guidelines and videos showing a couple of Cpp1 demo implementations.

from cppfront.

@JohelEGP wrote:

The whole file is Cpp1 syntax.

Yes, a .cpp2 file can be all today's syntax. That particular file was one of a series of demos that shows gradual migration from Cpp1 syntax to Cpp2 syntax so it started with Cpp2 syntax, so I checked it in when I checked in all my other test/demo files.

from cppfront.