" " \b0[xX][0-9a-fA-F]+ # hex number | \b ( \d+(\.[0-9]+)? #number with optional floating point | \.[0-9]+ #or just starting with floating point ) ([eE][+-]?[0-9]+)? # optional exponent ^%\S+ %% %% \$\$|\$\d+|@\d+|@\$ ^[a-zA-Z_][a-zA-Z_0-9]*