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更好看了，是吧？考慮到背景關係，我們可以很輕鬆地找到，這個方法在 activesupport/lib/active_support/core_ext/string/inflections.rb的第 205 行的 classify 方法，它看起來像這樣，是不是很容易？

# Creates a class name from a plural table name like Rails does for table names to models.
# Note that this returns a string and not a class. (To convert to an actual class
# follow +classify+ with +constantize+.)
#
#   'ham_and_eggs'.classify # => "HamAndEgg"
#   'posts'.classify        # => "Post"
    def classify
        ActiveSupport::Inflector.classify(self)
    end

儘管我們找到的這個方法是在 String 上的一個常見的呼叫，它呼叫了 ActiveSupport::Inflector 上的另一個同名的方法。根據之前的 git grep 的結果，我們可以很輕鬆地發現結果的第二行， activesupport/lib/active_support/inflector/methods.rb 在 186 行上。我們正在尋找的方法是這樣的：

# Creates a class name from a plural table name like Rails does for table
# names to models. Note that this returns a string and not a Class (To
# convert to an actual class follow +classify+ with constantize).
#
#   classify('ham_and_eggs') # => "HamAndEgg"
#   classify('posts')        # => "Post"
#
# Singular names are not handled correctly:
#
#   classify('calculus')     # => "Calculus"
def classify(table_name)
    # strip out any leading schema name
    camelize(singularize(table_name.to_s.sub(/.*\./, ''.freeze)))
end

酷！考慮到 Rails 倉庫的大小，我們藉助 git grep 找到它，用時都沒有超越 30 秒。

那麼，最後的變更是什麼？

現在，我們已經找到了所要找的方法，現在，我們需要搞清楚這個檔案所經歷的變更。由於我們已經知道了正確的檔案名和行數，我們可以使用 git blame。這個命令展示了一個檔案中每一行的最後修訂者和修訂的內容。我們來看一下這個檔案最後的修訂都做了什麼：

git blame activesupport/lib/active_support/inflector/methods.rb

雖然我們得到了這個檔案每一行的最後的變更，但是，我們更感興趣的是對特定方法（176 到 189 行）的最後變更。讓我們在 git blame 命令上增加一個選項，讓它只顯示那些行的變化。此外，我們將在命令上增加一個 -s （忽略）選項，去跳過那一行變更時的作者名字和修訂（提交）的時間戳：

git blame -L 176,189 -s activesupport/lib/active_support/inflector/methods.rb
9fe8e19a 176)   #Creates a class name from a plural table name like Rails does for table
5ea3f284 177)   # names to models. Note that this returns a string and not a Class (To
9fe8e19a 178)   # convert to an actual class follow +classify+ with #constantize).
51cd6bb8 179)   #
6d077205 180)   #   classify('ham_and_eggs') # => "HamAndEgg"
9fe8e19a 181)   #   classify('posts')        # => "Post"
51cd6bb8 182)   #
51cd6bb8 183)   # Singular names are not handled correctly:
5ea3f284 184)   #
66d6e7be 185)   #   classify('calculus')     # => "Calculus"
51cd6bb8 186)   def classify(table_name)
51cd6bb8 187)     # strip out any leading schema name
5bb1d4d2 188)     camelize(singularize(table_name.to_s.sub(/.*\./, ''.freeze)))
51cd6bb8 189)     end

git show 5bb1d4d2

git log -p activesupport/lib/active_support/inflector/methods.rb

git log -L 176,189:activesupport/lib/active_support/inflector/methods.rb

git log -L <start-line>,<end-line>:<path-to-file>

commit 51xd6bb829c418c5fbf75de1dfbb177233b1b154
Author: Foo Bar <foo@bar.com>
Date:   Tue Jun 7 19:05:09 2011 -0700
    Refactor
diff--git a/activesupport/lib/active_support/inflector/methods.rb b/activesupport/lib/active_support/inflector/methods.rb
--- a/activesupport/lib/active_support/inflector/methods.rb
+++ b/activesupport/lib/active_support/inflector/methods.rb
@@ -58,0 +135,14 @@
+    # Create a class name from a plural table name like Rails does for table names to models.
+    # Note that this returns a string and not a Class. (To convert to an actual class
+    # follow +classify+ with +constantize+.)
+    #
+    # Examples:
+    #   "egg_and_hams".classify # => "EggAndHam"
+    #   "posts".classify        # => "Post"
+    #
+    # Singular names are not handled correctly:
+    #   "business".classify     # => "Busines"
+    def classify(table_name)
+      # strip out any leading schema name
+      camelize(singularize(table_name.to_s.sub(/.*\./, '')))
+    end

git log -S 'def classify'

commit db045dbbf60b53dbe013ef25554fd013baf88134
Author: David Heinemeier Hansson <foo@bar.com>
Date:   Wed Nov 24 01:04:44 2004 +0000
    Initial
    git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@4 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

git show db045dbbf60b53dbe013ef25554fd013baf88134