数值的比较运算符

数值可以与 = 和其他数字比较运算符（/=，<，<=，>，>=）进行比较，忽略不同类型数字的物理表示的差异，并执行相应数学值的比较。例如：

(= 42 42)
T ;; => both number have the sme numeric type and the same value
(= 1 1.0 1d0)
T ;; => all the tree values represent the number 1, while for instance (eql 1 1d0) => NIL
  ;;    since it returns true only if the operands have the same numeric type
(= 0.0 -0.0)
T ;; => again, the value is the same, while (eql 0.0 -0.0) => NIL
(= 3.0 #c(3.0 0.0))
T ;; => a complex number with 0 imaginary part is equal to a real number
(= 0.33333333 11184811/33554432)
T ;; => since a float number is passed to RATIONAL before comparing it to another number
  ;; => and (RATIONAL 0.33333333) => 11184811/33554432 in 32-bit IEEE floats architectures
(= 0.33333333 0.33333334)
T ;; => since the result of RATIONAL on both numbers is equal in 32-bit IEEE floats architectures
(= 0.33333333d0 0.33333334d0)
NIL ;; => since the RATIONAL of the two numbers in double precision is different

从这些例子中，我们可以得出结论，= 是通常应该用来执行数值之间比较的运算符，除非我们要严格要求两个数值只有在它们具有相同数值类型时相等的事实，应该使用哪种情况 EQL。