map constructor idea, mooched from rdtsc

map-constructor.lisp

(defun make-map (pairs
                 &key
                   (test #'eql)
                   (default nil))
  "Creates a hash table with the list pairs; the CAR of each element
in the pairs is the key, the CDR is the value.

Hash table tests are :test

The default value of elements is `default`"
  (let ((new-hash (make-hash-table :test test)))
    (loop for (key . value) in pairs do
         (setf (gethash key new-hash default) (car value)))
    new-hash))

; CL-USER> (make-map '((1 2) (10 100) (30 "aaa")))
; #<HASH-TABLE :TEST EQL :COUNT 3 {1006A06183}>
; CL-USER> (print-hash-table-1 (make-map '((1 2) (10 100) (30 "aaa"))))   ;;print-hash-table-1 is a function I wrote
; 30 => aaa
; 10 => 100
; 1 => 2