#!/local/gauche/bin/gosh

;
; Blunders its way through an email header.
;

(use srfi-1)
(use srfi-13)

(define (process-field header-list line)
  (let ((ci  (string-index line #\:)))
    (if (not ci) (error "process-field: invalid current-line"))
    (acons (string-take line ci) (string-drop line (+ ci 1)) header-list)))

(define (read-field header-list current-line)
  (let ((new-line (read-line)))
    (if (or (eof-object? new-line) (string-null? new-line))
	(process-field header-list current-line)
	(let ((ci (string-skip new-line #[\s])))
	  (if (or (eqv? ci 0) (boolean? ci))
	      (process-field (read-field header-list new-line) current-line)
	      (read-field
	       header-list (string-join
			    (list current-line
				  (string-drop new-line ci)))))))))

(define (read-header)
  (let ((line  (read-line)))
    (if (eof-object? line)
	(list)
	(read-field (list) line))))

(define (print-all)
  (for-each 
   (lambda (thing)
     (print "X: " (car thing) ", " (cdr thing)))
   (read-header)))

(define (main args)
  (if (equal? (length args) 1)
      (print-all)
      (let ((header (read-header)))
	(print (cadr args) ": " (cdr (assoc (cadr args) header))))))