The hook_numberLines function automates line numbering on code blocks.

Basic usage

By default, the feature affects only source codes.

# By default, Source lines are numbered
"Output lines are not numbered"
## [1] "Output lines are not numbered"

The feature can be introduced to other types of code blocks as well, i.e. output, message, warning, and error.

hook_numberLines(c("source", "output"))
# After `hook_numberLines(c("source", "output"))`,
# Source lines are numbered
"Output lines are also numbered"
## [1] "Output lines are also numbered"

In order to disable the feature on selected chunks, specify the numberLines chunk option that determines which types of code blocks need line numbers.

# numberLines="output" is specified as a chunk option
# Source lines are not numbered
"Output lines are also numbered"
## [1] "Output lines are also numbered"