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;;;-*- Mode:LISP; Package:CHAOS; Base:10; Syntax:Common-lisp -*-
;;;
;;; Copyright (c) 2000-2015, Toshimi Sawada. All rights reserved.
;;;
;;; Redistribution and use in source and binary forms, with or without
;;; modification, are permitted provided that the following conditions
;;; are met:
;;;
;;; * Redistributions of source code must retain the above copyright
;;; notice, this list of conditions and the following disclaimer.
;;;
;;; * Redistributions in binary form must reproduce the above
;;; copyright notice, this list of conditions and the following
;;; disclaimer in the documentation and/or other materials
;;; provided with the distribution.
;;;
;;; THIS SOFTWARE IS PROVIDED BY THE AUTHOR 'AS IS' AND ANY EXPRESSED
;;; OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
;;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
;;; ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
;;; DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
;;; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
;;; GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
;;; INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
;;; WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
;;; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
;;; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
;;;
(in-package :chaos)
#|==============================================================================
System: Chaos
Module: primitives
File: context.lisp
==============================================================================|#
#-:chaos-debug
(declaim (optimize (speed 3) (safety 0) #-GCL (debug 0)))
#+:chaos-debug
(declaim (optimize (speed 1) (safety 3) #-GCL (debug 3)))
;;; DESCRIPTION
;;; all the functions which handle module's context.
;;;
;;; GET-CONTEXT : null | module
(defun get-context ()
(declare (optimize (speed 3) (safety 0)))
(if *current-module*
(module-context *current-module*)
nil))
;;; BINDINGS *******************************************************************
;;; GET-BOUND-VALUE : let-symbol -> value (a term) | null
(defun is-special-let-variable? (name)
(declare (type simple-string name))
(and (>= (length (the simple-string name)) 3)
(equal "$$" (subseq (the simple-string name) 0 2))))
(defun check-$$term-context (mod)
(declare (type module mod))
(or (eq $$term-context mod)
(member $$term-context
(module-all-submodules mod)
:test #'(lambda (x y)
(eq x (car y))))))
(defun get-bound-value (let-sym &optional (mod (get-context-module)))
(declare (type module mod)
(type simple-string let-sym))
(let ((bound-token (assoc let-sym (module-bindings mod) :test #'equal)))
(if (and (null bound-token) *allow-$$term*)
(cond ((equal let-sym "$$term")
(when (or (null $$term) (eq 'void $$term))
(with-output-simple-msg ()
(princ "[Error] $$term has no proper value.")
(throw 'term-context-error nil)))
(unless (check-$$term-context mod)
(with-output-simple-msg ()
(princ "[Error] $$term is not proper in the current module.")
(throw 'term-context-error nil)))
$$term)
((equal let-sym "$$subterm")
(unless $$subterm
(with-output-simple-msg ()
(princ "[Error] $$subterm has no proper vlaue.")
(throw 'term-context-error nil)))
(unless (check-$$term-context mod)
(with-output-simple-msg ()
(princ "[Error] $$subterm is not proper in the current module.")
(throw 'term-context-error nil)))
$$subterm)
((is-special-let-variable? let-sym)
(cdr (assoc let-sym (module-bindings mod) :test #'equal)))
(t nil))
(if bound-token
;; parse
(let* ((*parse-variables* nil)
(res (simple-parse-from-string (cdr bound-token) mod *cosmos*)))
(setq res (car (canonicalize-variables (list res) mod)))
res)
nil))))
(defun set-bound-value (let-sym value &optional (mod (get-context-module)))
(when (or (equal let-sym "$$term")
(equal let-sym "$$subterm"))
(with-output-chaos-error ('misc-error)
(princ "sorry, but you cannot use \"$$term\" or \"$$subterm\" as let variable.")))
;;
(let* ((special nil)
(bindings (if (is-special-let-variable? let-sym)
(progn (setq special t) (module-special-bindings mod))
(module-bindings mod))))
(let ((binding (assoc let-sym bindings :test #'equal)))
(if binding
(progn
(with-output-chaos-warning ()
(format t "resetting bound value of ~a to " let-sym)
(print-chaos-object value))
(setf (cdr binding) value))
(if special
(setf (module-special-bindings mod)
(acons let-sym value (module-special-bindings mod)))
(setf (module-bindings mod)
(acons let-sym value (module-bindings mod))))))))
;;; CHANGING CONTEXT
;;;-----------------------------------------------------------------------------
;;; change-context
;;; we must specially treat $$term, $$subterm, $$selection-stack, $$action-stack.
;;; these are also bound to global variables.
;;;
(defun save-context (mod)
(when (and mod (module-name mod))
(let ((context (module-context mod)))
(setf (module-context-$$term context) $$term
(module-context-$$subterm context) $$subterm
(module-context-$$action-stack context) $$action-stack
(module-context-$$selection-stack context) $$selection-stack
(module-context-$$stop-pattern context) *rewrite-stop-pattern*))))
(defun new-context (mod)
(unless mod
(setf $$term nil
$$subterm nil
$$action-stack nil
$$selection-stack nil
*current-module* nil
*rewrite-stop-pattern* nil)
(return-from new-context nil))
(let ((context (module-context mod)))
(setf $$term (module-context-$$term context)
$$subterm (module-context-$$subterm context)
$$action-stack (module-context-$$action-stack context)
$$selection-stack (module-context-$$selection-stack context)
*rewrite-stop-pattern* (module-context-$$stop-pattern context))
(setf $$term-context mod)
(reset-context-module mod)
(clear-method-info-hash)
t))
(defun change-context (from to)
(when (and to (module-is-inconsistent to))
(with-output-chaos-warning ()
(format t "specified module ~a is inconsistent" (module-name to))
(print-next)
(princ "due to some changes in its sub-module(s).")
(print-next)
(princ "context change is not performed."))
(return-from change-context nil))
;; save current context
(save-context from)
;; restore new context
(new-context to))
(defun reset-target-term (term old-mod mod)
(if (eq mod old-mod)
(progn
(setq $$term term
$$term-context mod
$$subterm term
$$selection-stack nil)
(save-context mod)
(new-context mod))
;; we do not change globals, instead set in context of mod.
(progn
(setq $$term-context mod)
(save-context mod))))
;;;
(defun context-push (mod)
(push mod *old-context*))
(defun context-pop ()
(pop *old-context*))
(defun context-push-and-move (old new)
(context-push old)
(change-context old new))
(defun context-pop-and-recover ()
(let ((old (context-pop)))
(unless (eq old (get-context-module t))
;; eval-mod may change the current context implicitly.
;; in this case we do not recover context.
(change-context (get-context-module t) old))))
;;; EOF
|
