logger 0.1 (2018-12-20)

Initial CRAN release after collecting feedback for a month on Twitter at https://twitter.com/daroczig/status/1067461632677330944:

• finalized design of a log request defined by

  • a log level threshold,
  • a formatter function preparing the log message,
  • a layout function rendering the actual log records and
  • an appender function delivering to the log destination

• detailed documentation with 7 vignettes and a lot of examples, even some benchmarks

• ~75% code coverage for unit tests

• 5 formatter functions mostly using paste, sprintf and glue

• 6 layout functions with convenient wrappers to let users define custom layouts via glue or JSON, including colorized output

• 5 appender functions delivering log records to the console, files, Pushbullet and Slack

• helper function to evaluate an expressions with auto-logging both the expression and its result

• helper function to temporarily update the log level threshold

• helper function to skip running the formatter function on a log message

• mostly backward compatibly with the logging and futile.logger packages