templater.ros

#!/bin/sh
#|-*- mode:lisp -*-|#
#|
exec ros -Q -L sbcl-bin -- $0 "$@"
|#
(progn
  (ros:ensure-asdf)
  #+quicklisp
  (ql:quickload '(djula)
                :silent t))

(defpackage :ros.script.templater
  (:use :cl))
(in-package :ros.script.templater)


(defun collect-arguments ()
  (let* ((env-output (with-output-to-string (s)
                       (uiop:run-program "env" :output s)))
         (lines (uiop:with-input (env-output)
                  (uiop:slurp-stream-lines env-output))))
    (loop for line in lines
          for (key value) = (cl-ppcre:split "=" line
                                            :limit 2)
          appending (list (alexandria:make-keyword key)
                          value))))


(defun interpose (separator list)
  "Returns a sequence of the elements of SEQUENCE separated by SEPARATOR."
  (labels ((rec (s acc)
             (if s
                 (rec (cdr s) (nconc acc
                                     (list separator (car s))))
                 acc)))
    (cdr (rec list nil))))


(defun main (&rest argv)
  (declare (ignore argv))
  (let* ((lines (uiop:slurp-stream-lines *standard-input*))
         (template-text (apply #'concatenate 'string
                               (interpose (string #\Newline)
                                          lines)))
         (template (djula::compile-string template-text))
         (arguments (collect-arguments)))
    (apply #'djula:render-template*
           template
           *standard-output*
           arguments)))

;;; vim: set ft=lisp lisp: