ruby koans don't understand the principle sandwhich code

rubyonrails-talk
1

hello,

Im still working on ruby koans. Now I have to do some sandwhich code.

The exercise looks like this :

require File.expand_path(File.dirname(FILE) + ‘/edgecase’)

class AboutSandwichCode < EdgeCase::Koan

def count_lines(file_name) file = open(file_name) count = 0 while line = file.gets count += 1 end count ensure file.close if file end

def test_counting_lines assert_equal 4, count_lines(“example_file.txt”) end

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def find_line(file_name) file = open(file_name) while line = file.gets return line if line.match(/e/) end ensure file.close if file end

def test_finding_lines assert_equal “test\n”, find_line(“example_file.txt”) end

------------------------------------------------------------------

THINK ABOUT IT:

2

But I don't get the principle.

There is no such principle as the Sandwich principle. The principle is Don't Repeat Yourself(DRY). So if you find yourself writing the same or similar code over and over again, try to figure out a way to extract the repeated part into a method. That way you can write the code once in the method, and then call the method when needed.