Default parsing format strings for chronons

Provides candidate format strings for parsing text into a given chronon (finest time granule), for use as the format argument of time_parse(). Dispatches the same way as chronon_format_linear()/chronon_format_cyclical(), but returns every common format instead of a single default, so time_parse() can try each in turn and keep whichever parses the most values. Methods should build their return value with parse_format().

Usage

chronon_parse_linear(x, cal = time_calendar(x), ...)

chronon_parse_cyclical(x, y, ...)

Arguments

x

A time granule for the chronon.

cal

The calendar of the chronon, used to disambiguate suitable format strings for time units that are shared across calendars (e.g. cal_gregorian$day and cal_isoweek$day).

...

Additional arguments for methods.

y

A time granule for the cycle

Value

A character vector of format templates, ordered from most to least common, built with parse_format(). The first element typically matches chronon_format_linear() (for chronon_parse_linear()) or chronon_format_cyclical() (for chronon_parse_cyclical()) for the same chronon.

See also

parse_format() for building candidate format strings (what these methods are built from), time_parse() for using the result as candidate formats, chronon_format_linear()/chronon_format_cyclical() for the single default format these are based on.

Examples

chronon_parse_linear(cal_gregorian$year(1L))
#> [1] "{lin(year)}"
chronon_parse_linear(cal_gregorian$month(1L))
#> [1] "{lin(year)}[-/,\\s]+{cyc(month,year)}"
#> [2] "{cyc(month,year)}[-/,\\s]+{lin(year)}"
#> attr(,"regex")
#> [1] TRUE
chronon_parse_linear(cal_gregorian$day(1L))
#> [1] "{lin(year)}[-/,\\s]+{cyc(month,year)}[-/,\\s]+{cyc(day,month)}(?:st|nd|rd|th)?"
#> [2] "{cyc(day,month)}(?:st|nd|rd|th)?[-/,\\s]+{cyc(month,year)}[-/,\\s]+{lin(year)}"
#> [3] "{cyc(month,year)}[-/,\\s]+{cyc(day,month)}(?:st|nd|rd|th)?[-/,\\s]+{lin(year)}"
#> attr(,"regex")
#> [1] TRUE
chronon_parse_linear(cal_isoweek$day(1L))
#> [1] "{lin(year)}[-\\s]*[Ww]{cyc(week,year)}[-\\s]+{cyc(day,week)}"
#> [2] "{cyc(day,week)}[-\\s]+[Ww]{cyc(week,year)}[-\\s]+{lin(year)}"
#> attr(,"regex")
#> [1] TRUE

chronon_parse_cyclical(cal_gregorian$month(1L), cal_gregorian$year(1L))
#> [1] "{cyc(month,year)}"
#> attr(,"regex")
#> [1] FALSE
chronon_parse_cyclical(cal_isoweek$day(1L), cal_isoweek$week(1L))
#> [1] "{cyc(day,week)}"
#> attr(,"regex")
#> [1] FALSE