Ruby-数组中的转义字符引发扫描

Question

I'm working on a simulation type thing based around arrays. I'm trying to make it so I can colour code the items in the array however for some reason when I write it out, the formatting is way off.

I believe this to be to do with the escape characters throwing off the scan (hence the title).

I've currently got this, (only relevant bits shown)

@width = 80
puts @world.join("").scan(/.{#{@width}}|.+/).join("\n\r")

Inside the array, I have strings and on some I have escape characters such as

"\\033[41mI\\033[0m"

Any ideas as to how I can fix this?

I can only guess but I think the escape parts are still being counted into the length when I call the scan on the array.

Thanks

Answer 1

You are right, the escape sequences count into the length of the string:

str = "\033[41mI\033[0m"
str.size                 #=> 10
str.scan(/./).to_a       #=> ["\e", "[", "4", "1", "m", "I", "\e", "[", "0", "m"]

The reason why your code fails is that you are using the regex to split the joined string up again, where one cell of the world suddenly occupies ten characters instead of just one. So, @width actually refers to the number of cells, not to the number of characters. As an alternative approach to building the output I suggest this method:

puts @world.each_slice(@width).map(&:join).join("\n\r")

It builds a nested array first, where each subarray consists of the same number of elements. This approach works as long as each cell only contains one visible character, which I simply assumed.