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Define Conditional Row Actions for Tables

Source: R/rowstyle_actions.R
compute_cols.Rd

Declares a set of styling, merging, and row insertion actions to be applied to rows matching a condition. Actions are captured as unevaluated expressions and evaluated later during create_report(). Supports complex conditions using data columns and helper functions.

Usage

compute_cols(spec, cond, ...)

Arguments

spec

A TFL_spec object (must have docType = "Table")

cond

An unquoted logical expression to be evaluated in the data environment. Can reference:

  • Data columns directly (e.g., col1 > 10, Parameter == "Pulse")

  • Helper functions (e.g., firstOf(), lastOf(), uniqueOf())

Must return a logical vector of length equal to nrow(data).

...

Action function calls: c_style(), c_merge(), c_addrow(), c_glue(), c_clear(). Multiple actions allowed, including duplicates. Actions are captured unevaluated.

Value

Modified spec object with appended action metadata in spec$.metadata$compute_cols. Invisibly returns the updated spec to enable piping workflows.

Details

Execution Timeline:

  1. compute_cols() captures condition and actions (no evaluation)

  2. Appends to spec$.metadata$compute_cols list

  3. During create_report(), conditions are evaluated and matched rows identified

  4. Actions are applied to matching rows (styling, merging, row insertion)

  5. StyleRows are serialized to JSON

Constraints:

  • Only allowed for docType = "Table"

  • Multiple compute_cols() calls accumulate on the same spec

  • Actions on the same row from different compute_cols() blocks are aggregated

  • Conditions must be deterministic (no NA values allowed)

Action Functions (used inside compute_cols()):

  • c_style(cols, styleRef): Apply style(s) to columns in matching rows

  • c_merge(cols, styleRef = NULL): Merge adjacent columns in matching rows

  • c_addrow(pos, value_from = NULL, styleRef = NULL): Insert row above/below matching rows

  • c_pageBreak(): Insert a page break at the matching row (no args)

  • c_glue(cols, position, glue_col = NULL, text = NULL, separator = NULL): Concatenate a data column value or literal text to matching cell text

  • c_clear(cols): Clear the display text of matching cells (render as blank)

See also

c_style(), c_merge(), c_addrow() for action functions used within compute_cols()

Examples

if (FALSE) { # \dontrun{
  spec <- create_table(mtcars)
  spec <- add_style(spec, id = "bold", s_font(bold = TRUE))
  spec <- add_style(spec, id = "red", s_font(color = "red"))
  spec <- add_style(spec, id = "highlight", s_table_style(background_color = "yellow"))

  # Style columns in rows where cyl is first occurrence
  spec <- compute_cols(spec, firstOf(cyl), c_style(c(mpg, hp), styleRef = "bold"))

  # Style and merge columns in rows with high hp
  spec <- compute_cols(spec, hp > 200, 
    c_style(hp, styleRef = "red"),
    c_merge(c(wt, qsec), styleRef = "highlight")
  )

  # Add empty separator row above first occurrence
  spec <- compute_cols(spec, firstOf(cyl), c_addrow(pos = "above"))

  # Add row with content from a column
  spec <- compute_cols(spec, lastOf(cyl), c_addrow(pos = "below", value_from = "mpg"))
} # }