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When a token is read, it is interpreted as a number or symbol. The token is interpreted as a number if it satisfies the syntax for numbers specified in Figure 2–9.
numeric-token ::= !integer | !ratio | !float
integer ::= [sign] {decimal-digit}^+ decimal-point | [sign] {digit}^+
ratio ::= [sign] {digit}^+ slash {digit}^+
float ::= [sign] {decimal-digit}* decimal-point {decimal-digit}^+ [!exponent]
| [sign] {decimal-digit}^+ [decimal-point {decimal-digit}*] !exponent
exponent ::= exponent-marker [sign] {digit}^+
sign—a sign.
slash—a slash
decimal-point—a dot.
exponent-marker—an exponent marker.
decimal-digit—a digit in radix 10.
digit—a digit in the current input radix.
Figure 2–9: Syntax for Numeric Tokens
| • Potential Numbers as Tokens | ||
| • Escape Characters and Potential Numbers | ||
| • Examples of Potential Numbers |