Adding support for symbols in fields.

.gitignore

@@ -1 +1,3 @@
 doc
+.DS_Store
+**/.DS_Store

lib/rrdb.rb

@@ -136,7 +136,8 @@ def self.config(hash_or_key = nil)
   # the values your application prefers.
   # 
   def self.field_name(name)
-    name.to_s.delete("^a-zA-Z0-9_")[0..18]
+    name.to_s.tr( "-~!@\#$%^&*+=|<>./?",
+                  "mtbahdpcnmveplgddq" ).delete("^a-zA-Z0-9_")[0..18]
   end
 
   #

test/tc_update.rb

@@ -48,10 +48,22 @@ def test_running_out_of_fields_to_claim_raises_fields_exhausted_error
   end
 
   def test_unsupported_characters_are_removed_from_names
-    @db.update(Time.now, "a'b=" => 4)
+    @db.update(Time.now, "a'b)" => 4)
     assert(@db.fields.include?("ab"), "Trimmed field name not found.")
   end
 
+  def test_common_symbols_are_translated
+    @db.update(Time.now, '~ z ! @#$%^&*-+=|<>./?' => 4)
+    assert( @db.fields.include?("tzbahdpcnmmveplgddq"),
+            "Common symbols were not translated." )
+  end
+
+  def test_fields_that_differ_only_by_symbol
+    @db.update(Time.now, "Swap Used" => 1, "% Swap Used" => 2)
+    assert(@db.fields.include?("SwapUsed"), "Non-symbol field was not found.")
+    assert(@db.fields.include?("pSwapUsed"), "Symbol field was not found.")
+  end
+
   def test_long_field_names_are_shortened_on_entry
     @db.update(Time.now, ("a".."z").to_a.join => 5)
     assert( @db.fields.include?(("a".."z").to_a.join[0..18]),
@@ -63,7 +75,7 @@ def test_field_names_must_be_at_least_one_supported_character_long
       @db.update(Time.now, String.new => 6)
     end
     assert_raise(RRDB::FieldNameConflictError) do
-      @db.update(Time.now, "!@\#$%^&*" => 7)
+      @db.update(Time.now, "`(){}[]'" => 7)
     end
   end