NAME

Slang::Roman - lets you use Roman numerals in your code

SYNOPSIS

use Slang::Roman;

say 0rI + 0rIX; # 10
my $i = 0rMMXVI; # $i = 2016

DESCRIPTION

This bit of admittedly twisted code let you use Roman numerals in your Raku code. It patches the running grammar so you can use a Roman numeral anywhere you would use a regular integer.

Future enhancements will include expansions to printf/sprintf with a custom formatting type, and the equivalents of hex() to handle string conversion.

While it handles both additive and subtractive Roman numerals, it doesn't check that they're properly formatted. For instance 'IC' should be a compile-time error but instead it'll generate 101 as if nothing of consequence happened.

REFERENCE

According to Wikipedia, the standard form is:

#	Thousands	Hundreds	Tens	Units
1	M	C	X	I
2	MM	CC	XX	II
3	MMM	CCC	XXX	III
4		CD	XL	IV
5		D	L	V
6		DC	LX	VI
7		DCC	LXX	VII
8		DCCC	LXXX	VIII
9		CM	XC	IX

Parameter kind	Example	Comment	Check for no arg passed
Slurpy	*@array	Don't check using .defined	if not @array
Required	$foo	Can't be omitted	(not applicable)
Optional	@bar = default	Pick a suitable default¹	if @bar =:= default

¹ A suitable default is an Object that has a distinct identity, as may be checked by the WHICH method.>

The numerals for 4 (IV) and 9 (IX) are written using subtractive notation,where the smaller symbol (I) is subtracted from the larger one (V, or X), thus avoiding the clumsier IIII and VIIII. Subtractive notation is also used for 40 (XL), 90 (XC), 400 (CD) and 900 (CM). These are the only subtractive forms in standard use.

AUTHOR

Jeff Goff (DrForr)

Source can be located at: https://github.com/raku-community-modules/Slang-Roman . Comments and Pull Requests are welcome.

COPYRIGHT AND LICENSE