token_is_on_aligned_line: Check if tokens are aligned

In r-lib/styler: Non-Invasive Pretty Printing of R Code

Check if tokens are aligned

Description

If all tokens are aligned, TRUE is returned, otherwise FALSE. The function only checks for alignment of function calls. This can be recycled conveniently later if needed as a vector with length > 1.

Usage

token_is_on_aligned_line(pd_flat)

Arguments

pd_flat

A flat parse table.

Details

Multiple lines are called aligned if the following conditions hold for all but the first line of the expression:

• lag spaces of column 1 must agree.

• spacing around comma (0 before, > 1 after) and spacing around = (at least one around).

• all positions of commas of col > 2 must agree (needs recursive creation of text).

Because of the last requirement, this function is very expensive to run. For this reason, the following approach is taken:

• Only invoke the function when certain that alignment is possible.

• Check the cheap conditions first.

• For the recursive creation of text, greedily check column by column to make sure we can stop as soon as we found that columns are not aligned.

Examples

library("magrittr")
withr::with_options(
  list(styler.cache_name = NULL), # temporarily deactivate cache
  {
    transformers <- tidyverse_style()
    pd_nested <- compute_parse_data_nested(c(
      "call(",
      "  ab = 1L,",
      "  a  = 2",
      ")"
    )) %>%
      styler:::post_visit(transformers$initialize)
    nest <- pd_nested$child[[1L]]
    styler:::token_is_on_aligned_line(nest)
  }
)

r-lib/styler documentation built on Dec. 13, 2024, 5:42 p.m.