;;; Host-level conventions shared by the Dat Scheme application layer.
;;; S7 intentionally leaves policy and application modules to its embedding.

(define dat:runtime-version "1")

(define (dat:module-name->file name)
  (if (not (symbol? name))
      (error 'wrong-type-arg "Dat module name must be a symbol" name)
      (if (eq? name 'dat:record)
          "dat-record.scm"
          (if (eq? name 'dat:wire)
              "dat-wire.scm"
              (let* ((text (symbol->string name))
                     (path (string-append text ".scm")))
                (do ((i 0 (+ i 1))) ((= i (string-length text)))
                  (if (char=? (string-ref text i) #\:)
                      (string-set! path i #\/)))
                path)))))

(define (dat:require feature)
  (let ((name (if (symbol? feature) feature (string->symbol feature))))
    (if (not (provided? name))
        (begin
          (load (dat:module-name->file name))
          (if (not (provided? name))
              (error 'dat-module-error "module did not declare its feature" name))))
    name))

(define (dat:with-archive archive procedure)
  (if (not (procedure? procedure))
      (error 'wrong-type-arg "expected a procedure" procedure)
      (dynamic-wind
        (lambda () #f)
        (lambda () (procedure archive))
        (lambda () (dat-close archive)))))

(define (dat:call-with-archive directory procedure . create?)
  (let ((archive ((if (and (pair? create?) (car create?)) dat-create dat-open)
                  directory)))
    (dat:with-archive archive procedure)))

(provide 'dat:runtime)