Initial release.

These are functions used to style code. They style a directory, a whole package,
a file or a string.
```
style_dir(path = ".",
  ..., style = tidyverse_style, transformers = style(...),
  filetype = "R", recursive = TRUE, exclude_files = NULL
)

style_pkg(pkg = ".",
  ..., style = tidyverse_style, transformers = style(...), filetype = "R",
  exclude_files = "R/RcppExports.R"
)

style_file(path,
  ..., style = tidyverse_style, transformers = style(...)
)

style_text(text, ..., style = tidyverse_style, transformers = style(...))
```

These functions are the style guides implemented.
```
tidyverse_style(
  scope = "tokens",
  strict = TRUE,
  indent_by = 2,
  start_comments_with_one_space = FALSE,
  reindention = tidyverse_reindention(),
  math_token_spacing = tidyverse_math_token_spacing()
)
tidyverse_reindention()
tidyverse_math_token_spacing())
```

This function is used to create a style guide.
```
createindention = NULL,
  use_raw_indention = FALSE,

adding examples to all exported functions

- Remove `regex_none()`, document `NULL` default.

- `style_dir()` and `style_pkg()` now also handle `.Rmd` files (r-lib#292, @jonmcalder).
- Add test for styling `.Rmd` files.
- Better error message for styling new files via the RStudio addin (r-lib#295).
- Spelling via devtools::spell_check() (r-lib#294).
- Roundtrip and CLI (r-lib#289).

- Adapt documentation (r-lib#290).

- Add roundtrip (r-lib#287).
- Fix AppVeyor builds.
- Fix token insertion / comment interaction (r-lib#279).
- Clarify labelling strategy (r-lib#285).
- Fixing and extending Rstudioaddins (r-lib#283).
- Fix eq assign parsing (r-lib#276).
- style_files -> vectorized style_file (r-lib#273).
- Refactoring (r-lib#270).
- Fix CI (r-lib#275).
- Fix covr (r-lib#274).
- Renaming files (r-lib#271).
- Handle styling of an unsaved active file (r-lib#243).
- Test R 3.1 and R 3.2 (r-lib#249).
- Allow empty {} without line break (r-lib#261).
- Wrap expr in expr before enclosing with curly braces (r-lib#263).
- Avoid checking for hard-coded dot (r-lib#262).
- Account for dependency renaming (utf8 changed to enc) (r-lib#264).
- Indention of function declaration and closing braces (r-lib#260).
- Only remove line break before closing with strict option (r-lib#252).

- Hotfix: utf8 should not be verbose (r-lib#245).

- Allow styling of Rmd files(r-lib#233).
- Remove duplicate @family (r-lib#244).
- Fixing token insertion (r-lib#242).
- Capitalize Addin titles (r-lib#241).
- Explicit `NULL` creation to make styler compatible with R3.2.0 (r-lib#237).
- Improve vignettes (r-lib#232).
- Allow exclusion of files with `style_pkg()` and `style_dir()`.
- Correct styling with long strings (r-lib#230).
- Add tools for re-indenting tokens (r-lib#217).
- Math token spacing (r-lib#221).
- Remove outdated line and col information (r-lib#218).
- Empty input for styling does not cause an error (r-lib#227, r-lib#228).
- Tools to insert tokens + application on `if`-`else` clauses (r-lib#212).
- Improve example in documentation (r-lib#222).
- Fix spacing around in (r-lib#214).
- Maintenance: renaming functions / files, extend helper, documentation, if_else etc. (r-lib#204).
- Disallow line break after ( for function calls (r-lib#210).
- Preserve space between `!` and bang (r-lib#209).
- Simplify RStudio Addin (r-lib#208, r-lib#211).
- Indention based on square brackets (r-lib#207).
- Add vignette on introducing styler (r-lib#203).
- Indent function declaration without curly braces correctly (r-lib#202).
- Fix indention in if-else statement (r-lib#200).
- Sorting key (r-lib#196).
- Use safe sequences (r-lib#197).
- Fix space between two commas (r-lib#195).
- Keep single-line pipes on one line (r-lib#74).
- Remove tidyr and dplyr dependency (r-lib#182, r-lib#183, @jimhester).
- Fix parsing inconsistency (r-lib#188).
- Substitute create filler (r-lib#190).
- Introducing class vertical (r-lib#189).
- Adapt line break rules (r-lib#172).
- Fix `R CMD check` (r-lib#185).
- Force argument evaluation for proper error handling (r-lib#179).
- Add nonstrict version of set_space_before_comment (r-lib#174).
- Add installation instructions to README (r-lib#175).
- Addin to style highlighted region (r-lib#143).
- Improve spelling (r-lib#168).
- Add coverage badge
- Change badge from WIP to active
- Add the number of files to message (r-lib#166).
- Improve documentation (r-lib#164).
- Add informative messages while styling files (r-lib#165).
- More examples in help file (r-lib#161).
- No line breaks after pipe if comment is next token (r-lib#160).
- Fixing spacing around `!` (non-bang-bang) (r-lib#157).
- Finalize function documentation (r-lib#154).
- Review vignette (r-lib#158).
- Update bang-bang rule (r-lib#156).

oops

- curly braces don't move a line up if previous token is comment.

- wrap parse + transform + serialize in new function.
- Speedup of nested styler functions by ~ 4x.
- Use multi line instead of line1 / line2 for indention and unindention.
- Indent multiple.
- add tidyverse rules (indention not yet working properly).
- Refactoring and add token before and afterwards to parse table.
- Implement post visitor instead of complicated move_up child.

* Tidy up README (r-lib#43).

* Fix indention of long operator chains (r-lib#69).
* Properly format unary operators (r-lib#38).
* Fixing indent multiple - one more time (r-lib#68).
* Remove spaces before comma (r-lib#62).
* Fixing indention with multiple parentheses (r-lib#57).
* data.tree gains unique node IDs for proper printing.
* Add `style_file()` function to style a single .R file.
* Add RStudio add-in to style active .R file.
* hotfix: make `style_pkg()` and `style_src()` work by passing flat
argument.

* Correctly deal with comments (spacing before comments, start commen…

…t with space)

* Test more flexibly (`test_collection()` and friends now support `...`)
* Indention based on curly brackets
* Spacing across different levels of nesting (e.g. a space after `)` in `function(x) {...}`)
* Write tree structure to file via test_collection()` for easy understanding of the nested structure
* Outsource tokenise
* Account for situations where code does not start on line1
* Correctly style comments
* Add style_empty for tailored testing
* Initialize indent in create filler
* Adapt vignette and documentation to visitor concept
* Refine testing to use visiting approach
* Parse multiple expressions: Make nested approach wok on multiple expressions too.
* Internal: introducing the visitor concept instead of "looping" many times through whole nested structure.
* Integrate nested approach in top-level APIs `style_text` and friends via an additional argument. `flat`.
* Add tools for scalable testing. Transform *-in.R with a transformer function and check whether result corresponds to *-out.R

- Fix `README.Rmd` for compatibility with pkgdown.