Megatest

				       (string-search whitesp key)
				       (string-search ":" key)) ;; internal only values to be skipped.
				   "# export "
				   "export ")
			       key "=" delim (mungeval val) delim)))
                    envvars)))))



















;; set some env vars from an alist, return an alist with original values
;; (("VAR" "value") ...)
;; a value of #f means "unset this var"
;;
(define (alist->env-vars lst)
  (if (list? lst)
      (let ((res '()))
	(for-each (lambda (p)
		    (let* ((var (car  p))
			   (val (cadr p))
			   (prv (get-environment-variable var)))
		      (set! res (cons (list var prv) res))
		      (if val 
			  (safe-setenv var (->string val))
			  (unsetenv var))))
		  lst)
	res)
      '()))


;; clear vars matching pattern, run proc, set vars back
;; if proc is a string run that string as a command with
;; system.
;;



(define (common:without-vars proc . var-patts)
  (let ((vars (make-hash-table)))
    (for-each
     (lambda (vardat) ;; each env var
       (for-each
	(lambda (var-patt)
	  (if (string-match var-patt (car vardat))

     (proc          (proc)))
    (hash-table-for-each
     vars
     (lambda (var val)
       (setenv var val)))
    vars))

(define (common:get-param-mapping #!key (flavor #f))
  "returns alist mapping string keys in testconfig/subrun to megatest command line switches; if flavor is switch-symbol, maps tcmt symbolic switches to megatest switches"
  (let ((default '(("tag-expr"  . "-tagexpr")
                   ("mode-patt" . "-modepatt")
                   ("run-name"  . "-runname")
                   ("contour"   . "-contour")
                   ("mode-patt" . "-mode-patt")
                   
                   ("test-patt" . "-testpatt")
                   ("msg"       . "-m")
                   ("new"       . "-set-state-status"))))
    (if (eq? flavor 'switch)
        (map (lambda (x)
               (cons (string->symbol (conc "-" (car x)) (cdr x))))
             default)
        default)))

(define (common:sub-megatest-selector-switches test-run-dir)
  (let* ((switch-def-alist (common:get-param-mapping flavor: 'config)))
         (subrunfile   (conc test-run-dir "/testconfig.subrun" ))
         (subrundata   (with-input-from-file subrunfile read))
         (subrunconfig (configf:alist->config subrundata)))
  ;; note - get precmd from subrun section
  ;;   apply to submegatest commands

  (apply append
           (filter-map (lambda (item)
                         (let ((config-key (car item))
                               (switch     (cdr item))
                               (val        (configf:lookup subrunconfig switch)))
                           (if val
                               (list switch val)
                               #f)))
                       switch-def-alist))))

(define (common:sub-megatest-run test-run-dir switches #!key (logfile #f))
  (let* ((real-logfile (or logfile (conc (test-run-dir) "/subrun-"
                                         (string-substitute "[/*]" "_" (string-intersperse switches "^"))"-"
                                         (number->string (current-seconds)) ".log")))
         (selector-switches  (common:sub-megatest-selector-switches test-run-dir))
         (cmd-list `("megatest" ,@selector-switches ,@switches "-log" ,real-logfile))
         )
    (call-with-environment-variables 
     (list (cons "PATH" (conc (get-environment-variable "PATH") ":.")))
     (lambda  ()
       (common:without-vars proc "^MT_.*")
       
       ))))
                             


(define (common:run-a-command cmd #!key (with-vars #f))
  (let* ((pre-cmd  (dtests:get-pre-command))
         (post-cmd (dtests:get-post-command))
         (fullcmd  (if (or pre-cmd post-cmd)
                       (conc pre-cmd cmd post-cmd)
                       (conc "viewscreen " cmd))))