Added quoted identifiers.

Author: Dray Lacy

lib/sql/parser.rex

@@ -77,6 +77,7 @@ rule
             ,           { [:comma, text] }
 
 # identifier
+            `{IDENT}`   { [:identifier, text[1..-2]] }
             {IDENT}     { [:identifier, text] }
 
 ---- header ----

lib/sql/parser.rex.rb

@@ -203,6 +203,9 @@ def scan_evaluate( str )
         when (text = ss.scan(/,/))
            @rex_tokens.push action { [:comma, text] }
 
+        when (text = ss.scan(/`\w+`/))
+           @rex_tokens.push action { [:identifier, text[1..-2]] }
+
         when (text = ss.scan(/\w+/))
            @rex_tokens.push action { [:identifier, text] }
 

test/test_parser.rb

@@ -193,6 +193,10 @@ def test_numeric_value_expression
     assert_understands 'SELECT (1 - 2)'
   end
 
+  def test_quoted_identifier
+    assert_sql 'SELECT a', 'SELECT `a`'
+  end
+
   def test_date
     assert_sql "SELECT DATE '2008-07-11'", 'SELECT DATE "2008-07-11"'
     assert_understands "SELECT DATE '2008-07-11'"