Style a roxygen code example segment — style_roxygen_code_example

A roxygen code example segment corresponds to roxygen example code that contains at most one \\dontrun{...} or friends. We drop all newline characters first because otherwise the code segment passed to this function was previously parsed with parse_roxygen() and line-breaks in and after the \\dontrun{...} are expressed with "\n", which contradicts to the definition used elsewhere in this package, where every element in a vector corresponds to a line. These line-breaks don't get eliminated because they move to the front of a code_segment and style_text("\n1") gives "\n1", i.e. trailing newlines are not eliminated.

style_roxygen_code_example_segment(one_dont, transformers, base_indention)

Arguments

one_dont: Bare R code containing at most one \\dontrun{...} or friends.
transformers: Passed to cache_make_key() to generate a key.
base_indention: Integer scalar indicating by how many spaces the whole output text should be indented. Note that this is not the same as splitting by line and add a base_indention spaces before the code in the case multi-line strings are present. See 'Examples'.

Hierarchy

Styling involves splitting roxygen example code into segments, and segments into snippets. This describes the process for input of parse_transform_serialize_roxygen():

Splitting code into roxygen example code and other code. Downstream, we are only concerned about roxygen code. See parse_transform_serialize_roxygen().
Every roxygen example code can have zero or more dontrun / dontshow / donttest sequences. We next create segments of roxygen code examples that contain at most one of these. See style_roxygen_code_example().
We further split the segment that contains at most one dont* sequence into snippets that are either don* or not. See style_roxygen_code_example_segment().

Finally, that we have roxygen code snippets that are either dont* or not, we style them in style_roxygen_example_snippet() using parse_transform_serialize_r().