Migrate std::bind calls to lambda expressions

[FelipeGdM]

As discussed in this issue, most of the examples in the docs were written using the C++11 function std::bind, which is similar to the ROS 1 way of doing things with boost::bind. In later revisions of C++, lambda expressions became more powerful and today are consider to be more "idiomatic" than std::bind

This PR migrates the C++ examples that use std::bind to equivalent lambda expression code

The affected examples are:

• Writing a simple C++ publisher and subscriber
• Using parameters in a class (C++)
• Using callback groups
• FastDDS configuration
• Reading from a bagfile (C++)
• Recording a bag from your own node (C++)
• Custom ROS 2 interfaces
• Adding a tf2 frame (C++)
• Writing a tf2 broadcaster (C++)
• Writing a tf2 listener (C++)
• Writing an action server client (C++)

In the original issue, it's said that it would be interessant to keep some exemples with std::bind as a way to show that it's a possible way to do things in C++. I personally don't know which criteria would be better to choose which example to keep using std::bind, so a listed them all above so other people may say what they think 😁

Closes #3618

[sloretz]

@tylerjw mind reviewing this one, and checking if the demos and examples need updating to match? 🧇

https://github.com/ros2/demos
https://github.com/ros2/examples

[tylerjw]

I carefully read through these changes and did not find any errors. There is one small question about creating named lambdas vs using temporaries and what I think might be a small typo.

I found the PR to the examples repo but not one to the demos repo. Would you mind updating the demos repo too?

[FelipeGdM]

@tylerjw thank you for your review!

I found the PR to the examples repo but not one to the demos repo. Would you mind updating the demos repo too?

I can also create a PR to update the demos repo, sounds reasonable to me

[fujitatomoya]

@FelipeGdM thanks for your contribution.

i have a quick question.

https://github.com/ros2/ros2_documentation/blob/rolling/source/Tutorials/Advanced/Simulators/Webots/Code/MyRobotDriver.cpp#L28

and

https://github.com/ros2/ros2_documentation/blob/rolling/source/Tutorials/Advanced/Simulators/Webots/Code/ObstacleAvoider.cpp#L10-L15

are excluded intentionally? i guess. since those are examples for Webots?

[FelipeGdM]

@fujitatomoya they were not excluded intentionally, it was an oversight on my part 🤦

I will include them in the migration

[tylerjw]

Reviewed the latest changes and they look good. Thank you for the PR to the demos repo.

[FelipeGdM]

@clalancette I'm sorry, I didn't understand the issue. As far as I understood, the PR ros2/examples#317 adds examples for services using lambdas, but the file you mentioned is about topics.

I can see that the PR performs some cosmetic changes in the topics lambda example, such as adding comments here and there, but the code is essentially the same.

I may be missing something in the relationship between the docs and the examples, if that's the case it would be fine to remove this change and create a draft PR with it and merge once the other one is closed.

[fujitatomoya]

lgtm

[clalancette]

@clalancette I'm sorry, I didn't understand the issue. As far as I understood, the PR ros2/examples#317 adds examples for services using lambdas, but the file you mentioned is about topics.

No, you are right. When I looked at it, I got confused. This part of it is OK, I'll resolve that conversation.

[clalancette]

A few more updates (mostly to the geometry_tutorials), then I think this will be good to go.

[FelipeGdM]

@clalancette I just created the PR in the geometry_tutorials repo and resolved the conversations

[clalancette]

Thanks for all of the work to push this over the line. I suspect that there will be small followups in the next couple of weeks, but this looks good to me so I'll go ahead and merge it.

[Ryanf55]

Great to see this in!