Named regexes

• Regexes can be given names

regex integer { <[+\-]>? \d+ }
regex ident { <alpha> \w* }
regex sigil { '$' | '@' | '%' | '&' }

• Those names can be re-used in other regexes

regex fraction { <integer> '/' <integer> }

regex variable { <sigil> <ident> }