---
title: "Number lines on code blocks"
output: rmarkdown::html_vignette
vignette: >
  %\VignetteIndexEntry{Number lines on code blocks}
  %\VignetteEngine{knitr::rmarkdown}
  %\VignetteEncoding{UTF-8}
---

The `hook_numberLines` function automates line numbering on code blocks.

```{r setup}
library(chunkhooks)
hook_numberLines()
```

# Basic usage

By default, the feature affects only source codes.

```{r}
# By default, Source lines are numbered
"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.

```{r}
hook_numberLines(c("source", "output"))
```

```{r}
# After `hook_numberLines(c("source", "output"))`,
# Source lines are numbered
"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.

```{r, numberLines="output"}
# numberLines="output" is specified as a chunk option
# Source lines are not numbered
"Output lines are also numbered"
```