calrom

Command line utility providing access to the Roman Catholic liturgical calendar (post-Vatican II).

Built on top of the calendarium-romanum Ruby gem.

calrom is a Ruby gem:

$ gem install calrom

Print liturgical calendar for the current month (default):

$ calrom

... for a specified month of the current year:

$ calrom -m 9

... for a specified month of another year:

$ calrom -m 1 2028 or $ calrom 1 2028

... for a whole year:

$ calrom 2017

... for the current year:

$ calrom -y

... for a specified date:

$ calrom 2028-01-15

... for an arbitrary date range:

$ calrom 2028-01-15 2028-03-07

In addition to specifying date range, filtering is a way to further refine the selection of data to be displayed. Options --day-filter= and --celebration-filter= both accept a snippet of Ruby code, which is then evaled in context of each CalendariumRomanum::Day / CalendariumRomanum::Celebration within the selected date range and only days/celebrations for which the expression evaluates truthy are displayed.

Display only Saturdays:

$ calrom --day-filter='date.saturday?'

Display all Mondays with a celebration of a rank higher than memorial:

$ calrom --day-filter='date.monday?' --day-filter='celebrations[0].rank > MEMORIAL_GENERAL'

(As you can see, calendarium-romanum constants like ranks or seasons are available as top-level constants. Noone likes extensive writing in the terminal.)

Display only ferials:

$ calrom --celebration-filter='ferial?'

Display only celebrations in green:

$ calrom --celebration-filter='colour == GREEN'

The options can be combined and used repeatedly to narrow the selection down as needed.

There are a few calendars bundled in calrom (actually in the calendarium-romanum gem) and ready to use. List them:

$ calrom --calendars

Each entry of the listing contains an ID of the calendar, it's name and language code. Use calendar ID to request General Roman Calendar in Latin:

$ calrom --calendar=universal-la

You can prepare your own calendar data and load them:

$ calrom --calendar=path/to/my_calendar.txt

If you specify more than one calendar, they are loaded "layered" one over another (from left to right), which comes in handy when extending a general calendar with just a few additional and/or differing celebrations, e.g. solemnities (titular, dedication) of the local church:

$ calrom --calendar=universal-la --calendar=path/to/our_local_celebrations.txt

Please note that specifying more than one calendar disables automatic loading of parent calendars. If any of the listed calendars extends a parent calendar, the parent either has to be explicitly listed using the --calendar option in order to be loaded, or automatic parent loading has to be explicitly enabled using the --load-parents option.

Limited support for remote calendars is provided. Calendar URL from the Liturgical Calendar API or a compatible calendar API is accepted as a value of --calendar=:

$ calrom --calendar=http://calapi.inadiutorium.cz/api/v0/en/calendars/general-la

Print detailed listing:

$ calrom -l

Print current day in a condensed format (intended mainly for use cases like window manager toolbars):

$ calrom --format=condensed --today

Disable colours:

$ calrom --no-color

Machine-readable output formats:

$ calrom --format=json - prints JSON array containing one object per day. The object contents mimick output of the Church Calendar API v0.

$ calrom --format=csv - prints a CSV, one celebration per line (i.e. there is one or more lines for each liturgical day).

calrom looks for configuration files /etc/calromrc and ~/.calromrc. They are processed in this order and both are used if available. Their syntax is that of shell options and arguments (with the sole exception that newline is not considered end of shell input, but generic whitespace), supported are all options and arguments accepted by the command.

If a custom configuration file location is specified on the command line, $ calrom --config=path/to/my/custom/config, the standard system-wide and user-specific configuration files are not loaded. Empty config path $ calrom --config= makes calrom ignore all configuration files and use the built-in default configuration.

Example configuration file, loading the proper calendar of the archdiocese of Prague and disabling colours:

# shell-like comments can be used in configuration files

--calendar=czech-praha-cs # calendar of the archdiocese of Prague
--calendar=~/calendar_data/local_church.txt # path to a custom calendar file with proper celebrations of the parish where I live (titular feast of the church, dedication)

--load-parents # load also parent calendars specified by the calendar file(s)
               # (default if just one calendar file is specified, but we specified two)

--no-color # disable colours

(Configuration file format is inspired by .rspec, .yardopts and others.)

Most options work in such a way that if several conflicting options are provided, the last one wins. You can thus e.g. set your favourite display format (e.g. --list) or date range (e.g. -3) in the configuration file and override it, if necessary, by providing some other option from the same group on the command line. An exception from this rule is the --calendar= option, repeated occurrences of which do not cancel each other, but are all composed together in the given order to build a calendar by layering. Also repeated occurrences of the --day-filter= and --celebration-filter= options don't cancel each other, but all specified filtering expressions are applied.

Clone the repository, $ bundle install to install dependencies, then:

$ rake cucumber - run specs describing the command line interface

$ rake spec - run specs describing internal implementation details

$ rake - run all groups of specs one after another

• detailed listing of a day/month/year/range of dates
• month/year overview - options and output mostly mimicking the BSD Unix cal utility, but with liturgical colours and celebration ranks
• condensed format (but with detailed information) suitable for awesome/i3 toolbars etc.
• machine-readable detailed listing
• year summary: lectionary cycles, movable feasts
• configuration file to set default options
• specify calendar data path (with support for layering several calendars)
• option to auto-select one of optional celebrations - with multiple supported strategies (prefer ferial, take first non-ferial, configured whitelist, blacklist)
• integrate online data sources

Project adheres to semantic versioning with regard to the command line interface: between major releases, the same configuration (through command line options and other ways of configuration the application will eventually support) should print information of the same (or greater) level of detail for the same range of dates. For output formats explicitly documented as machine-readable, format must be preserved (where some machine-readable formats, especially the structured ones, allow backward-compatible extensions, others do not, according to their nature).

No backward compatibility is guaranteed on the level of the application's internal interfaces, since they are not intended to be used by third-party code.

When designing new elements (options, arguments) of the command line interface

• (BSD version of) cal should be mimicked where reasonable
• the Command-Line Options chapter from E. S. Raymond's The Art of Unix Programming should be consulted in the rest of cases

GNU/GPL 3.0 or later