DRAFT: Reading decimals

2026-09-08

• #en
• #lisp

Three approaches

The straight forward one. Note that I don't have to map the index to power myself.

(defun octet-to-decimal (octet)
  (loop :for i :from 0 :upto 7
        :for power :from -1 :downto -8
        :when (logbitp i octet)
          :sum (expt 2 power)))

The one middle ground one. Where we pre-compute every power at read time and just sum them.

  (defun octet-to-decimal (octet)
    (loop :for i :from 0 :upto 7
       :for n :in #.(loop :for power :from -1 :downto -8
                          :collect (expt 2 power))

          :when (logbitp i octet)
            :sum n))

The last one is a hash table for every possible combination.