Improve function detection to avoid accidental conversion

[Maran23]

Fixes: #74650

This PR improves the function detection in the project converter by checking if the function really is standalone and not part of a method or similar.
E.g. when checking and converting a function like connect(, we do not want to detect and convert a function like reconnect(.

We achieve this by checking the previous character when the function name is detected in a line.
To recognize the function as standalone and not as part of a name, the following previous characters are checked:

• A-Za-z0-9 -> econnect or 9connect - not a function call
• _ -> _connect - not a function call
• $-> $connect - not a function call
• @-> @connect - not a function call

Or in other words:

• connect() is a function call
• connect() is a function call
• object.connect() is a function call

[akien-mga]

Technically other preceding characters like [ or % or + might be valid. It's maybe better to check that the preceding character is not alphanumeric or _? Thankfully Godot 3 doesn't support extended ASCII/Unicode identifiers.

Otherwise, the approach in this PR is probably "good enough" for the use case, so we can also stick to this if preferred.

[Maran23]

Technically other preceding characters like [ or % or + might be valid. It's maybe better to check that the preceding character is not alphanumeric or _?

I thought about this as well. But wasn't sure if I may miss something.
If I understand correctly, checking for A-Za-z0-9 and _ will catch all possible characters here?

[akien-mga]

If I understand correctly, checking for A-Za-z0-9 and _ will catch all possible characters here?

Yeah that seems correct:

godot/core/ustring.cpp

Line 3392 in 26a5841

return (p_char >= '0' && p_char <= '9') || (p_char >= 'a' && p_char <= 'z') || (p_char >= 'A' && p_char <= 'Z') || p_char == '_';

There could also be things like $connect to fetch a node with name "connect" but that wouldn't have ( at the end so it should be fine.

[Maran23]

Yeah that seems correct:

godot/core/ustring.cpp

Line 3392 in 26a5841

return (p_char >= '0' && p_char <= '9') || (p_char >= 'a' && p_char <= 'z') || (p_char >= 'A' && p_char <= 'Z') || p_char == '_';

Changed the logic to match the if statement above. This is approach is much safer. Thanks!

[Maran23]

There could also be things like $connect to fetch a node with name "connect" but that wouldn't have ( at the end so it should be fine.

I think it makes sense to also check for the "$" sign. Since in this case it is also not a function call.

[akien-mga]

Sorry for the delay reviewing. Looks good to me!

[akien-mga]

Thanks!

[Reneator]

Thanks so much!