Extract a function to determine if the default value is a function

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -59,7 +59,7 @@ def initialize(name, default, oid_type, sql_type = nil, null = true)
           super(name, default_value, sql_type, null)
         end
 
-        @default_function = default if !default_value && default && default =~ /.+\(.*\)/
+        @default_function = default if has_default_function?(default_value, default)
       end
 
       # :stopdoc:
@@ -142,6 +142,10 @@ def type_cast(value)
 
       private
 
+        def has_default_function?(default_value, default)
+          !default_value && (%r{\w+(.*)} === default)
+        end
+
         def extract_limit(sql_type)
           case sql_type
           when /^bigint/i;    8