Returns true if the string contains only Octal digits

assert "213453".is_oct  == true
assert "781".is_oct     == false

Property definitions

core $ Text :: is_oct
	# Returns `true` if the string contains only Octal digits
	#
	# ~~~
	# assert "213453".is_oct  == true
	# assert "781".is_oct     == false
	# ~~~
	fun is_oct: Bool do
		for i in chars do if i < '0' or i > '7' then return false
		return true
	end
lib/core/text/abstract_text.nit:404,2--413,4