Remove call stack section

[c-martinez]

The Call Stack section of the python counterpart of this lesson has been removed from the lesson and moved to the discussion page.

As mentioned in this PR, it would be good to know whether instructors teaching this lesson tend to skip this section and thus it could be removed?

My guess is that, ideally, we would like the R and Python lessons to be as similar as possible (except when it comes to language-specific lessons). Is this right?

[jdblischak]

Thanks for the PR, @c-martinez. I agree we should remove this section from the main lesson. While instructive for reading, it is difficult to teach in a workshop setting. In r-novice inflammation, we often put supplemental content in "supp" files. Could you please put the call stack section in a new section titled 02-supp-call-stack.Rmd? Then add a callout section in 02-func-R.Rmd that links to this supplemental content. Please let me know if you have any questions.

[c-martinez]

Hi @jdblischak , I've added the 02-supp-call-stack.Rmd fine and a .callout section. I hope this is fine now.

[jdblischak]

It's looking good, @c-martinez. Three minor things.

Each file needs a YAML header so that it is properly rendered online. Please add the following to the very top of the file 02-supp-call-stack.Rmd.

---
layout: page
title: Programming with R
subtitle: The call stack
minutes: 15
---

The callout section as it is has no context. The word "call stack" is not used before this point, so the title "Further details" is not correct since no details on the call stack have been given. Could you please title the callout box "The call stack" and then give a brief description? Maybe something like "For a deeper understanding of how functions work, you'll need to learn how they create their own environments and call other functions. Function calls are managed via the call stack. For more details on the call stack, have a look at the supplementary material."

The call stack is still included in the key points at the bottom of the lesson. Could you please move this key point to the supplementary file?

[c-martinez]

Hi @jdblischak, I've incorporated the changes you suggested. I hope this is fine now.

[chendaniely]

from the knitr documentation: hide hides results; this option only applies to normal R output (not warnings, messages or errors)

if we actually execute the below block of code in this document, we have an error:
## Error in eval(expr, envir, enclos): could not find function "outside"

maybe use eval=FALSE instead?