Alignment detection

Sometimes, you deliberately align code to make it more readable.

  a =       3,
  b = 3213232

Until styler (with strict = TRUE, e.g. as in styler::style_file(..., strict = TRUE)), this was formatted as follows:

  a = 3,
  b = 3213232

because no alignment detection was built in.1

styler >= detects aforementioned alignment for function calls. This vignette describes how aligned code is defined in styler and gives some examples so users can format their aligned code to match the definition styler uses to ensure their code is not unintentionally reformatted.

An important definition used in the remainder is the one of a column. All arguments of a function call that have the same position but are placed on different lines form a column. The below call shows a call with two columns and two rows. Columns separate arguments of the function call, so the separator is the comma. The first row is named because all arguments are named, the second is unnamed:

  # column 1  | column 2 |
  abkj = f(2),         7,
  more_ = "a", 2 # more

Function calls

Non-technical definition

Below, we try to explain in an intuitive way how your code should look like to be recognized as aligned.

If all arguments in the first column are named: Make commas match position vertically and right align everything between commas:

If not all arguments of the first column are named:2 Make all except the first column’s commas match position

By align everything in between the commas, we mean put zero space before a comma and at least one after. Note that the arguments on the first line are ignored when detecting alignment, which is best shown when code is formatted such that no line breaks will be modified by styler. This applies if all names on the first line are unnamed and all subsequent are named:


These typical examples match styler’s definition of alignment.

Technical definition

This section closely follows the implementation of the alignment detection and is mostly aimed at developers for understanding styler internals.

Function calls are aligned if all of the following conditions hold (for all but the very first line (i.e. call( below):

Note that the above definition does not check alignment of =, so styler will treat the following as aligned:


not supported yet.


not supported yet.

  1. With strict = FALSE, the spacing would have been kept, however, strict = FALSE has a number of other implications because it is in general less invasive. For example, it would not add braces and line breaks to “if (TRUE) return()”.

  2. In the below example, the first argument of the first column is named (p = 2). The second argument of the first column is not (31).