If you want to change the behavior of styler to match your desired style, there are multiple ways:
Use the tidyverse style guide, but not with the default options. Starting point for this approach is the
help("tidyverse_style")for the functiontidyverse_style(), which returns the transformer functions that prettify your code. Most of these options are explained invignette("styler").If you can’t get styler behaving the way you want using the arguments of
tidyverse_style(), you have another option, which is described in avignette("customizing_styler"): Creating your own style guide from scratch. Yes, I admit, it’s pretty long and if you don’t want to become a styler expert, it may be a little bit overwhelming.If you don’t care about how to create new rules but you simply want to remove a rule, I have good news for you: There is a quick way to do it. And that’s what the remainder of this vignette focuses on.
Once you are happy with your style guide, you might want to have a
look at how to distribute it, which is described in
vignette("distribute_custom_style_guides").
Theory
Here are the steps required to deactivate a rule you don’t like
Figure out which transformer function in the transformers returned by
tidyerse_style()corresponds to the rule you want to remove.Set that element in the list to
NULL, which is equivalent to removing it.Pass the list to
style_textas a transformer.
Practice
Lets assume you want to remove the rule that turns =
into <- for assignment. That means you want
string = "hi there" to remain unchanged after applying styler. This is not the case if you use the default style guide of styler:
library(styler)
style_text("string = 'hi there'")
string <- "hi there"So you need to figure out which rule is responsible for this. Let’s check the transformer categories used with the tidyverse style guide.
transformers <- tidyverse_style()
names(transformers)
#> [1] "initialize" "line_break" "space"
#> [4] "token" "indention" "use_raw_indention"
#> [7] "reindention" "style_guide_name" "style_guide_version"
#> [10] "more_specs_style_guide" "transformers_drop" "indent_character"From the aforementioned vignette:
We note that there are different types of transformer functions. initialize initializes some variables in the nested parse table (so it is not actually a transformer), and the other elements modify either spacing, line breaks or tokens. use_raw_indention is not a function, it is just an option.
Now, we can look at the names of the rules that are sub-elements of the transformer categories.
library(magrittr)
levels <- c("space", "line_break", "indention", "token")
purrr::map(
levels,
~ names(transformers[[.x]])
) %>%
purrr::set_names(levels)
#> $space
#> [1] "remove_space_before_closing_paren" "remove_space_before_opening_paren"
#> [3] "add_space_after_for_if_while" "remove_space_before_comma"
#> [5] "style_space_around_math_token" "style_space_around_tilde"
#> [7] "spacing_around_op" "remove_space_after_opening_paren"
#> [9] "remove_space_after_excl" "set_space_after_bang_bang"
#> [11] "remove_space_before_dollar" "remove_space_after_fun_dec"
#> [13] "remove_space_around_colons" "start_comments_with_space"
#> [15] "remove_space_after_unary_pm_nested" "spacing_before_comments"
#> [17] "set_space_between_levels" "set_space_between_eq_sub_and_comma"
#> [19] "set_space_in_curly"
#>
#> $line_break
#> [1] "remove_empty_lines_after_opening_and_before_closing_braces"
#> [2] "set_line_break_around_comma_and_or"
#> [3] "set_line_break_after_assignment"
#> [4] "set_line_break_before_curly_opening"
#> [5] "remove_line_break_before_round_closing_after_curly"
#> [6] "remove_line_breaks_in_fun_dec"
#> [7] "style_line_break_around_curly"
#> [8] "set_line_break_around_curly_curly"
#> [9] "set_line_break_before_closing_call"
#> [10] "set_line_break_after_opening_if_call_is_multi_line"
#> [11] "remove_line_break_in_fun_call"
#> [12] "add_line_break_after_pipe"
#> [13] "set_line_break_after_ggplot2_plus"
#>
#> $indention
#> [1] "indent_braces" "unindent_fun_dec"
#> [3] "indent_op" "indent_eq_sub"
#> [5] "indent_without_paren" "update_indention_ref_fun_dec"
#>
#> $token
#> [1] "fix_quotes"
#> [2] "force_assignment_op"
#> [3] "resolve_semicolon"
#> [4] "add_brackets_in_pipe"
#> [5] "wrap_if_else_while_for_fun_multi_line_in_curly"Spotted the rule we want to get rid of? It’s under token
and it’s called force_assignment_op. I agree, we could have
chosen a better name. If you are not sure if you can guess from the name
of the rule what it does you can also have a look at the function
declaration of this (unexported) function.
styler:::force_assignment_op
#> function (pd)
#> {
#> to_replace <- pd$token == "EQ_ASSIGN"
#> pd$token[to_replace] <- "LEFT_ASSIGN"
#> pd$text[to_replace] <- "<-"
#> pd
#> }
#> <bytecode: 0x56402e473668>
#> <environment: namespace:styler>Next, you simply set that element to NULL.
transformers$token$force_assignment_op <- NULLAnd you can use the modified transformer list as input to
style_text()
style_text("string = 'hi there'", transformers = transformers)
#> string = "hi there"If you want to use it the same way as tidyverse_style(),
here’s the last step:
eq_assign_style <- function(...) {
transformers <- tidyverse_style(...)
transformers$token$force_assignment_op <- NULL
transformers
}
style_text("string = 'hi there'", style = eq_assign_style)
#> string = "hi there"That’s it. Note that the transformer functions and how they are
returned by tidyverse_style() is not part of the exposed
API. This means that the order, the naming etc. may change. Also,
remember we did not add a rule to replace <- with
=, but we only removed a rule to replace =
with <-, so <- won’t be touched:
style_text("string <- 'hi there'", style = eq_assign_style)
#> string <- "hi there"If you want to turn <- into =, you need
to add a rule as described in
vignette("customizing_styler").
If you have trouble identifying a rule based on rule names,
- First write an example whose results is not the one you wanted, e.g.
code <- "
f <- function () {
return (1)
}"is code that will have the first empty line in the function body removed by styler.
- Then pinpoint the probable rule type (e.g. line breaks if you want less new lines).
- In a local styler clone, add e.g. a
return(pd)at the top of the body to deactivate the rule quickly, or add aprint(pd)orbrowser()call in the functions of that type (e.g. the different functions ofR/rules-line-breaks.R),load_all(), run your example, see if that function made the change. move theprint(pd)orbrowser()call to another function if not. - Once you’ve identified the culprit (in this case
style_line_break_around_curly), set it toNULLas shown earlier.
Some other rules and their transformers
You don’t like multi-line ifelse statements getting wrapped around curly braces:
transformers$token$wrap_if_else_multi_line_in_curly.You don’t like multi-line calls to be broken before the first named argument:
transformers$line_break$set_line_break_after_opening_if_call_is_multi_line(interacting withtransformers$line_break$set_line_break_before_closing_call).You don’t like the line being broken after the pipe:
transformers$line_break$add_line_break_after_pipeYou don’t like single quotes to be replaced by double quotes:
transformers$space$fix_quotes.You don’t like comments to start with one space:
transformers$space$start_comments_with_space
I think you get the idea. I nevertheless recommend using the tidyverse style guide as is since
it is a well-established, thought-through style.
using a consistent style (no matter which) reduces friction in the community.
If you have questions, don’t hesitate to create an issue in the GitHub repo.