error_if {msgr}

Display an error, and record in a log file, if a condition is true.

Description

This function calls the error() function to display an error if the specified condition is true. If a message is not specified then a generic message is displayed.

Usage

error_if(
  condition,
  ...,
  level = 1,
  msg_level = getOption("msgr.level"),
  msg_types = getOption("msgr.types"),
  log_path = getOption("msgr.log_path")
)

Arguments

condition

(boolean) The condition to check.

...

(strings) message to be displayed or written to file.

level

(integer, optional) The level of the message, from 1 to 10. Default: 1.

msg_level

(integer, optional) The maximum level of messages to output. Default: set in the option "msgr.level".

msg_types

(character, optional) The type to write or display. Must either NULL or one or more from "INFO", "WARNING" or "ERROR". Default: set in the option "msgr.types".

log_path

(string, optional) The file path to the text log file. If set to "", then no logs are written. Default: set in the option "msgr.log_path".

Value

A string is return invisibly containing the error

Examples

## Not run: 
  # Use error_if() to create conditional timed errors
  error_if(2 > 1, "Condition is true so this error is shown")
  error_if(1 > 2, "Condition is false so this error is not shown")

  # As with error() a level can be set
  error_if(2 > 1, "This is a level 2 error, so not shown by default", level = 2)

  # Set default level in options to determine what is shown
  options(msgr.level = 2)
  error_if(2 > 1, "This is a level 2 error, so is shown now", level = 2)

## End(Not run)