warn {msgr}

Display a warning, and record it in a log file.

Description

warn() is similar to warning(), but it also writes the warning to a log file. Whether it is shown, or written to the log, depends on the level and type of the warning. See details below for more information.

Usage

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

Arguments

...

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

level

(integer, optional) The level of the warning, 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".

Details

Whether a warning is shown, or written to the log, depends on two options:

1. Level: This allows control over the depth of messages. Each message can be assigned a level and if it is below the msg_level (set in the package option msgr.level by default) the message is displayed and written to the log.

2. Type: The type is refers to whether the message is "INFO", "WARNING" or "ERROR", as produced by the functions info(), warn() and error() respectively. If the message type is in the msg_types (set in the package option msgr.types by default) the message is displayed and written to the log. This allows you to for instance, just display errors and warnings and ignore messages.

The location of the log file is set in the package option msgr.log_path, or as an argument to this function. messages are added with a time stamp. If the log_path is equal to "" then no log is produced.

Value

A string is return invisibly containing the warning

Examples

# Use warn() to create timed warnings
warn("This is a simple warning")
warn("This is a level 2 warning, so not shown by default", level = 2)

# Set default level in options to determine what is shown
options(msgr.level = 2)
warn("This is a level 2 warning, so is shown now", level = 2)

# Set message types in options to determine what is shown
options(msgr.types = "ERROR")
warn("This is warning, so will not be shown now")