telent

App configuration in environment variables: for and against

For (some of these as per the 12 factor principles) 

1) they are are easy to change between deploys without changing any code

2) unlike config files, there is little chance of them being checked
into the code repo accidentally

3) unlike custom config files, or other config mechanisms such as Java

cky

(use-srfis '(1 69))
(read-hash-extend #\#
  (lambda (c port)
    (define ht (make-hash-table eqv?))
    (define (ht-ref key)
      (hash-table-ref ht key (lambda ()
                               (define sym (gensym))
                               (hash-table-set! ht key sym)
                               sym)))
    (define (hash-key x)