# File lib/dbi/sql.rb, line 152
    def tokens(sql)
      sql.scan(%r{
        (
            -- .*                               (?# matches "--" style comments to the end of line or string )
        |   -                                   (?# matches single "-" )
        |
            /[*] .*? [*]/                       (?# matches C-style comments )
        |   /                                   (?# matches single slash )    
        |
            ' ( [^'\\]  |  ''  |  \\. )* '      (?# match strings surrounded by apostophes )
        |
            " ( [^"\\]  |  ""  |  \\. )* "      (?# match strings surrounded by " )
        |
            \?\??                               (?# match one or two question marks )
        |
            [^-/'"?]+                           (?# match all characters except ' " ? - and / )
            
        )}x).collect {|t| t.first}
    end