-;;; tram.el --- basic session framework for internet protocols
-
-;; Copyright (C) 2000 Daiki Ueno
-
-;; Author: Daiki Ueno <ueno@unixuser.org>
-;; Created: 2000/08/14
-
-;; This file is part of FLIM (Faithful Library about Internet Message).
-
-;; This program is free software; you can redistribute it and/or
-;; modify it under the terms of the GNU General Public License as
-;; published by the Free Software Foundation; either version 2, or (at
-;; your option) any later version.
-
-;; This program is distributed in the hope that it will be useful, but
-;; WITHOUT ANY WARRANTY; without even the implied warranty of
-;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-;; General Public License for more details.
-
-;; You should have received a copy of the GNU General Public License
-;; along with this program; see the file COPYING. If not, write to the
-;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-;; Boston, MA 02111-1307, USA.
-
-
-;;; Commentary:
-;;
-
-;;; Code:
-
-(require 'luna)
-(require 'closure)
-
-(eval-when-compile (require 'cl))
-
-(eval-and-compile
- (luna-define-class tram-stream ())
-
- (luna-define-internal-accessors 'tram-stream))
-
-(luna-define-generic tram-stream-error-name (stream)
- "Return error symbol of the STREAM.")
-
-(luna-define-generic tram-stream-error (stream error)
- "Throw an ERROR of the STREAM.")
-
-(luna-define-method tram-stream-error-name ((stream tram-stream))
- (intern (format "%s-error" (luna-class-name stream))))
-
-(luna-define-method tram-stream-error ((stream tram-stream) error)
- (throw (tram-stream-error-name stream) error))
-
-(put '&& 'tram-compose-function #'tram-compose-&&)
-(put '|| 'tram-compose-function #'tram-compose-||)
-
-(defun tram-compose-&& (left right)
- "Multiplicative combinator which composes LEFT and RIGHT operations."
- `(lambda (stream)
- (let ((next
- ,(if (functionp left)
- `(closure-call #',left stream)
- `(closure-call ',left stream))))
- ,(if (functionp right)
- `(closure-call #',right next)
- `(closure-call ',right next)))))
-
-(defun tram-compose-|| (left right)
- "Additive combinator which composes LEFT and RIGHT operations."
- `(lambda (stream)
- (let (next error)
- (setq error
- (catch (tram-stream-error-name stream)
- (setq next
- ,(if (functionp left)
- `(closure-call #',left stream)
- `(closure-call ',left stream)))
- nil))
- (if error
- ,(if (functionp right)
- `(closure-call #',right next)
- `(closure-call ',right next))
- next))))
-
-(defun tram-fold-left (function accu sequence)
- "Apply FUNCTION to ACCU while folding SEQUENCE from left to right."
- (if (null sequence)
- accu
- (tram-fold-left
- function (funcall function accu (car sequence))
- (cdr sequence))))
-
-;;;###autoload
-(defmacro tram-define-transaction (name tram-transaction &optional doc)
- "Set NAME the compiled code of TRAM-TRANSACTION."
- `(let ((transaction
- ,(tram-compose-transaction (eval tram-transaction))))
- (defconst ,name transaction ,doc)))
-
-;;;###autoload
-(defun tram-compose-transaction (tram-transaction)
- "Compose transaction-function from TRAM-TRANSACTION."
- (if (not (symbolp (car tram-transaction)))
- tram-transaction
- (let ((combinator
- (get (pop tram-transaction) 'tram-compose-function)))
- (or combinator
- (error "Unknown operator"))
- (tram-fold-left
- `(lambda (accu c)
- (funcall
- #',combinator accu
- (if (listp c)
- (tram-compose-transaction c)
- c)))
- (if (listp (car tram-transaction))
- (tram-compose-transaction (pop tram-transaction))
- (pop tram-transaction))
- tram-transaction))))
-
-(provide 'tram)
-
-;;; tram.el ends here