diff --git a/tool/unicode_norm_gen.rb b/tool/unicode_norm_gen.rb
index c90b16dac5..982f3f077c 100644
--- a/tool/unicode_norm_gen.rb
+++ b/tool/unicode_norm_gen.rb
@@ -46,7 +46,7 @@ class Array
       else
         first.to_UTF8 + '-' + last.to_UTF8
       end
-    end.line_slice "\" +\n    \""
+    end.line_slice "\" \\\n    \""
   end
 end
 
@@ -141,33 +141,42 @@ open("#{OuputDataDir}/normalize_tables.rb", "w").print <<MAPPING_TABLE_FILE_END
 # automatically generated by tool/unicode_norm_gen.rb
 
 module Normalize
-  ACCENTS = "
-    [#{accent_array.to_regexp_chars}]
-  "
-  REGEXP_D_STRING = "  # composition starters and composition exclusions
-    [#{(composition_table.values+composition_exclusions).to_regexp_chars}]\#{ACCENTS}*
-    |  # characters that can be the result of a composition, except composition starters
-    [#{(composition_starters-composition_table.values).to_regexp_chars}]?\#{ACCENTS}+
-    |  # precomposed Hangul syllables
-    [\\u{AC00}-\\u{D7A4}]
-  "
-  REGEXP_C_STRING = "  # composition exclusions
-    [#{composition_exclusions.to_regexp_chars}]\#{ACCENTS}*
-    |  # composition starters and characters that can be the result of a composition
-    [#{(composition_starters+composition_table.values).to_regexp_chars}]?\#{ACCENTS}+
-    |  # Hangul syllables with separate trailer
-    [#{hangul_no_trailing.to_regexp_chars}][\\u11A8-\\u11C2]
-    |  # decomposed Hangul syllables
-    [\\u1100-\\u1112][\\u1161-\\u1175][\\u11A8-\\u11C2]?
-  "
-  REGEXP_K_STRING = "
-    [#{kompatible_table.keys.to_regexp_chars}]
-  "
+  accents = "" \\
+    "[#{accent_array.to_regexp_chars}]" \\
+  ""
+  ACCENTS = accents
+  REGEXP_D_STRING = "\#{''  # composition starters and composition exclusions
+    }" \\
+    "[#{(composition_table.values+composition_exclusions).to_regexp_chars}]\#{accents}*" \\
+    "|\#{''  # characters that can be the result of a composition, except composition starters
+    }" \\
+    "[#{(composition_starters-composition_table.values).to_regexp_chars}]?\#{accents}+" \\
+    "|\#{''  # precomposed Hangul syllables
+    }" \\
+    "[\\u{AC00}-\\u{D7A4}]" \\
+  ""
+  REGEXP_C_STRING = "\#{''  # composition exclusions
+    }" \\
+    "[#{composition_exclusions.to_regexp_chars}]\#{accents}*" \\
+    "|\#{''  # composition starters and characters that can be the result of a composition
+    }" \\
+    "[#{(composition_starters+composition_table.values).to_regexp_chars}]?\#{accents}+" \\
+    "|\#{''  # Hangul syllables with separate trailer
+    }" \\
+    "[#{hangul_no_trailing.to_regexp_chars}][\\u11A8-\\u11C2]" \\
+    "|\#{''  # decomposed Hangul syllables
+    }" \\
+    "[\\u1100-\\u1112][\\u1161-\\u1175][\\u11A8-\\u11C2]?" \\
+  ""
+  REGEXP_K_STRING = "" \\
+    "[#{kompatible_table.keys.to_regexp_chars}]" \\
+  ""
 
-  CLASS_TABLE = {
+  class_table = {
     #{class_table_str}
   }
-  CLASS_TABLE.default = 0
+  class_table.default = 0
+  CLASS_TABLE = class_table
 
   DECOMPOSITION_TABLE = {
     #{decomposition_table.to_hash_string}