script to generate crontab syntax from clean human-friendly input?

Is there a tool or scripting language that will allow me to create a crontab-syntax output after supplying a human-friendly specification or initialization file?

For example:

 when: every 2 hours
 what: system('/path/to/flush_system_logs')

 when: 4:45pm every Wednesday
 what: system('/path/to/system_janitor_script')

I would like to supply a specification like that, and either have a process that can run cron from the specification, OR create a crontab fil开发者_高级运维e that stays in sync with the spec.

Here are a few on-line crontab generators:

• http://www.openjs.com/scripts/jslibrary/demos/crontab.php
• http://crontab-generator.com/
• http://www.clockwatchers.com/cron_tool.html
• http://www.htmlbasix.com/crontab.shtml