An HTML Calendar Generator

Awhile back I replaced the (increasingly unwieldy) monthly archive section over there in the right-hand column with a yearly archive section: one link per year that Pun Salad has been in existence. Each link takes you to a yearly calendar, which, in turn, contains links to the monthly archives (when you click on a month name) or daily posts (when you click on a day). Example output here for 2017.

The code to generate those calendars is embedded in the (very) special purpose CGI script that powers Pun Salad, but I thought the calendar generation code might be of interest to people. So, shorn of all the blog-specific stuff: Perl script here, prettyprinted HTML here.

Notes:

  • The script is run with a single year argument, and produces HTML on standard output.

  • The Perl module Time::Piece does most all of the heavy lifting for the necessary date calculations. It probably breaks down for years far in the past or future; I haven't messed with that too much. I tested that it gives the same calendar for 1901 as the Linux cal command does, so that's good.

  • The HTML::Template module is used to specify the HTML framework for the calendar. Obviously, that's where you might want to customize the appearance. The bare-bones template is here. (The code assumes the template resides in your top-level ~/Templates directory.)

  • The calendar is a table of months; each month is a table of days. This means, of course, that the generator is essentially a four-deep nested loop. Eek! A voice from my old structured programming days said: "you really shouldn't nest loops that deeply". So I broke out the month-generation into a Perl subroutine, and now I feel better about myself.

As usual, this is not earth-shattering code, but I hope someone finds it useful, if only for tutorial purposes.