(define-module (language python exceptions)
  #:use-module (oop pf-objects)
  #:use-module (oop goops)
  #:export (StopIteration GeneratorExit RuntimeError
                          Exception))

(define-syntax-rule (aif it p x y) (let ((it p)) (if it x y)))

(define StopIteration 'StopIteration)
(define GeneratorExit 'GeneratorExit)
(define RuntimeError  'RuntimeError)

(define-python-class Exception ()
  (define __init__
    (case-lambda
      ((self)
       (values))
      ((self str)
       (set self 'str str))))
                 
  (define __repr__
    (lambda (self . l)
      (define port (if (pair? l) (car l) #f))
      (aif it (ref self 'str)
           (format port "~s: ~a"
                   (ref self '__name__) it)
           (format port "~s"
                   (ref self '__name__))))))