As examples, the tokens in the next figure are potential numbers, but they are not actually numbers, and so are reserved tokens; a conforming implementation is permitted, but not required, to define their meaning.
1b5000 777777q 1.7J -3/4+6.7J 12/25/83 27^19 3^4/5 6//7 220.127.116.11 ^-43^ 3.141_592_653_589_793_238_4 -3.7+2.6i-6.17j+19.6k
Figure 2-10. Examples of reserved tokens
The tokens in the next figure are not potential numbers; they are always treated as symbols:
/ /5 + 1+ 1- foo+ ab.cd _ ^ ^/-
Figure 2-11. Examples of symbols
The tokens in the next figure are potential numbers if the current input base is 16, but they are always treated as symbols if the current input base is 10.
bad-face 25-dec-83 a/b fad_cafe f^
Figure 2-12. Examples of symbols or potential numbers