[Asterisk-Users] Holiday Scheduling

[Derek Beaumont]

I want to edit my dialplan to change messages depending on whether or
not it is a holiday.

I have found only one example of this, but the syntax is not explained.

The example is:
include=>holiday||||1|jan|

I know that this would use the holiday context on the first of January,
but why are there 4 pipes before 1

What is the exact syntax of this?
Let's say that I want to use the holiday context on Jan 1, Oct 31, and
Dec 31.  How would I write that into my dialplan?

Thanks for your time