Implemented day1 of advent of code.

src/advent/day1.rb

@@ -1,15 +1,33 @@
 # frozen_string_literal: true
 
+DIGIT_NAMES = {one: "1", two: "2", three: "3", four: "4" ,
+               five: "5", six: "6", seven: "7", eight: "8",
+               nine: "9"}
+def extracts_digits (word, ret=[])
+  if word == nil || word.empty?
+    return ret
+  end
+  if word.start_with? /\d/
+    ret.append word[0]
+    return extracts_digits word[1..], ret
+  end
+
+  DIGIT_NAMES.each do |name, value|
+    if word.start_with? name.to_s
+      ret.append  value
+      return extracts_digits word[1..], ret
+    end
+  end
+  extracts_digits word[1..], ret
+end
+
+
 def fist_letter(line)
-  line.split("").each do |x|
-    if x.match?(/\d/)
-      return x
-    end
-  end
+  extracts_digits(line)[0]
 end
 
 def last_digit(line)
-  fist_letter line.reverse
+  extracts_digits(line)[-1]
 end
 
 def get_calibration_code(line)
@@ -27,7 +45,15 @@ def get_sum_of_calibration_code(document)
   calibration_codes.reduce 0, :+
 end
 
+# puts "on".length
+
+# puts extracts_digits "7pqrstsixteen"
+mock_input = "
+8nine37bpkmtghhnc2hnreightwohvs
+"
+
 input_file_name = File.join(File.dirname(__FILE__), "day_1_input.txt")
 
 input_content = File.open(input_file_name).read
 puts get_sum_of_calibration_code(input_content)
+# puts extracts_digits mock_input