begin = '(?x)
			   (?:
			     ^                      # beginning of line
			   | (?<=                   # or look-behind on:
			       [=>~(?:\[,|&]
			     | (?:\s|;)when\s
			     | (?:\s|;)or\s
			     | (?:\s|;)and\s
			     | (?:\s|;|\.)index\s
			     | (?:\s|;|\.)scan\s
			     | (?:\s|;|\.)sub\s
			     | (?:\s|l|\.)sub!\s
			     | (?:\s|;|\.)gsub\s
			     | (?:\s|;|\.)gsub!\s
			     | (?:\s|;|\.)match\s
			     | (?:\s|;)if\s
			     | (?:\s|;)elsif\s
			     | (?:\s|;)while\s
			     | (?:\s|;)unless\s
			     )
			   | (?<=                  # or a look-behind with line anchor:
			        ^when\s              # duplication necessary due to limits of regex
			      | ^index\s
			      | ^scan\s
			      | ^sub\s
			      | ^gsub\s
			      | ^sub!\s
			      | ^gsub!\s
			      | ^match\s
			      | ^if\s
			      | ^elsif\s
			      | ^while\s
			      | ^unless\s
			      )
			   )
			   \s*((/))(?![*+{}?])
			';