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Print a styled alert message

Source: R/utils-logging.R
print_alert.Rd

A flexible wrapper for cli alert functions that uses cli's theming system for consistent styling. Supports glue-style interpolation including cli in-line text formatting for the following: {.val ...}; {.arg ...}; {.field ...} and {.path ...}. Moreover, each of these in-line values is rendered in a distinct highlight color (defaulting to "grey98"), making it easy to draw attention to specific variables or values within the message. The alert type controls the leading icon, while the base text color and font face can be customized for further emphasis.

Usage

print_alert(
  text,
  type = "n",
  face = "n",
  color = "grey80",
  highlight_color = "grey98",
  .envir = parent.frame()
)

Arguments

text

Character string. The message to display. Supports cli glue-style interpolation and inline markup (e.g. {.val x}, {.emph x}, {?singular/plural}).

type

Character string. Alert type controlling the leading icon:

"s"

Success (green tick)

"d"

Danger (red cross)

"w"

Warning (orange exclamation)

"i"

Info (blue/cyan 'i')

"n"

Plain text, no icon (default)

Any other value falls back to a generic alert (arrow).

face

Character string. Font face applied to the base text:

"n"

Normal / plain (default)

"b"

Bold

"i"

Italic

"bi"

Bold italic

color

Character string. Base text color applied to the message body. Accepts standard color names (e.g. "red") or hex codes (e.g. "#FF5733"). Defaults to "grey80".

highlight_color

Character string. Color applied to {.val ...}; {.arg ...}; {.field ...} and {.path ...} spans. Each of the aforementioned spans are rendered using their default themes: only the colour is changed according to this argument which accepts the same values as color and defaults to "grey98".

.envir

Environment used for glue interpolation. Defaults to the caller's environment so that variables referenced in text are resolved from the calling scope.

Value

Invisible NULL; called for its side effect of printing a formatted message to the console.

Details

Styling is applied via start_app themes rather than pre-wrapping the text in ANSI codes. This ensures that cli's own inline markup ({.val}, {.emph}, etc.) composes correctly with the user-specified base color and face.

The "n" (plain) alert type uses cli_text under the body theme class, producing output with no icon and no leading whitespace — visually identical to the other alert types minus the bullet character.

Examples

if (FALSE) { # \dontrun{
  # Plain message — no icon, default grey
  print_alert("Starting process...")

  # Highlight interpolated values
  n <- 5
  print_alert("Loaded {.val {n}} sample{?s}", type = "s", color = "green")

  # Warning with italic text and custom highlight
  print_alert("Column {.val {col}} has missing values",
              type = "w", color = "orange", face = "i",
              highlight_color = "yellow")

  # Bold italic danger alert
  print_alert("Fatal: {.val {msg}}", type = "d", color = "red", face = "bi")
} # }