Added expr parameter to monitor() for executing arbitrary R expressions when files change, as an alternative to running R scripts via the file parameter.
Added support for natural R syntax using curly braces {} for multi-line expressions.
Added capture_output parameter to control whether expression output is captured and displayed (default: TRUE).
Added on_error parameter to control behavior when expression execution fails ("continue" or "stop").
Updated function documentation with comprehensive examples showing both string and language object expressions.
Updated README with detailed examples of expression execution features.
testthat for CRAN compliance.