// Flexer generator's input own lexer specification
line-comment 	-> "//[^\n\r]+" flex-skip .
block-comment	-> "/\*(?ms:.)*?\*/" flex-skip .
dot          	-> '\.' .
literal-string  -> `"` flex-esc-string  .
literal-raw     -> "`" flex-string  .
literal-char    -> "'" flex-string  .
terminal     	-> "[[:lower:]][[:alnum]_-]+" .
epsilon      	-> "(?:epsilon|ε)" .
arrow        	-> "(?:->|→)" .
flexer-keyword	-> "flex-skip|flex-string|flex-esc-string" .
whitespace   	-> "[ \t\n\r]+" flex-skip .
flexer-action   -> `@{(?ms:.)*?}@`
@{
// This is the rule action.
@ { } @
}@
.