Support for @examplesIf roxygen tag

[krlmlr]

for #742. Ideally we'd add full support for @examplesIf, this gets us halfway. Not sure the final //s* is necessary.

Needs tests.

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Here is how the current PR would change benchmark results when merged into master:

• cache_applying: 0.03 -> 0.03 (-1.3%)
• cache_recording: 1.19 -> 1.19 (-0.4%)
• without_cache: 3.44 -> 3.46 (0.6%)

Here is how the current PR would change benchmark results when merged into master:

• cache_applying: 0.03 -> 0.03 (-0.2%)
• cache_recording: 0.88 -> 0.88 (0.2%)
• without_cache: 2.57 -> 2.56 (-0.4%)

[codecov-io]

Codecov Report

Merging #743 (c65e562) into master (179a85a) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #743      +/-   ##
==========================================
+ Coverage   90.53%   90.56%   +0.02%     
==========================================
  Files          47       47              
  Lines        2389     2395       +6     
==========================================
+ Hits         2163     2169       +6     
  Misses        226      226              

Impacted Files	Coverage Δ
R/roxygen-examples-add-remove.R	92.30% <100.00%> (-1.03%)	⬇️
R/roxygen-examples-find.R	100.00% <100.00%> (ø)
R/roxygen-examples-parse.R	96.66% <100.00%> (+0.51%)	⬆️
R/roxygen-examples.R	97.91% <100.00%> (ø)

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[lorenzwalthert]

@krlmlr you can try this if you want, should work now. Maybe have a look at the test cases too and tell me if we miss anything...

[krlmlr]

Looks good, thanks for the effort! I didn't review all the examples, will file new issues if anything breaks in practice.

[krlmlr]

This matches @examples If . Just sayin...

Can you use the regex from https://github.com/r-lib/styler/pull/743/files#diff-73645d1e1e747d5eeb45cbd47ddb2ef64c658ed5c585763efd004a1b08ba61f9R10, perhaps with rematch2 and a grouped match?

[lorenzwalthert]

Good catch. I didn't ever figure out how to use {rematch2} (and did not bother spending time), maybe I should... For now, I think using the regex you linked should be sufficient.