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-rw-r--r--libguile/dynwind.c148
1 files changed, 148 insertions, 0 deletions
diff --git a/libguile/dynwind.c b/libguile/dynwind.c
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+++ b/libguile/dynwind.c
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+/* Copyright (C) 1995,1996 Free Software Foundation, Inc.
+ *
+ * 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 software; see the file COPYING. If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * As a special exception, the Free Software Foundation gives permission
+ * for additional uses of the text contained in its release of GUILE.
+ *
+ * The exception is that, if you link the GUILE library with other files
+ * to produce an executable, this does not by itself cause the
+ * resulting executable to be covered by the GNU General Public License.
+ * Your use of that executable is in no way restricted on account of
+ * linking the GUILE library code into it.
+ *
+ * This exception does not however invalidate any other reasons why
+ * the executable file might be covered by the GNU General Public License.
+ *
+ * This exception applies only to the code released by the
+ * Free Software Foundation under the name GUILE. If you copy
+ * code from other Free Software Foundation releases into a copy of
+ * GUILE, as the General Public License permits, the exception does
+ * not apply to the code that you add in this way. To avoid misleading
+ * anyone as to the status of such modified files, you must delete
+ * this exception notice from them.
+ *
+ * If you write modifications of your own for GUILE, it is your choice
+ * whether to permit this exception to apply to your modifications.
+ * If you do not wish that, delete this exception notice.
+ */
+
+
+#include <stdio.h>
+#include "_scm.h"
+
+
+
+/* {Dynamic wind}
+ */
+
+
+
+SCM_PROC(s_dynamic_wind, "dynamic-wind", 3, 0, 0, scm_dynamic_wind);
+#ifdef __STDC__
+SCM
+scm_dynamic_wind (SCM thunk1, SCM thunk2, SCM thunk3)
+#else
+SCM
+scm_dynamic_wind (thunk1, thunk2, thunk3)
+ SCM thunk1;
+ SCM thunk2;
+ SCM thunk3;
+#endif
+{
+ SCM ans;
+ scm_apply (thunk1, SCM_EOL, SCM_EOL);
+ scm_dynwinds = scm_acons (thunk1, thunk3, scm_dynwinds);
+ ans = scm_apply (thunk2, SCM_EOL, SCM_EOL);
+ scm_dynwinds = SCM_CDR (scm_dynwinds);
+ scm_apply (thunk3, SCM_EOL, SCM_EOL);
+ return ans;
+}
+
+#ifdef __STDC__
+void
+scm_dowinds (SCM to, long delta)
+#else
+void
+scm_dowinds (to, delta)
+ SCM to;
+ long delta;
+#endif
+{
+ tail:
+ if (scm_dynwinds == to);
+ else if (0 > delta)
+ {
+ SCM wind_elt;
+ SCM wind_key;
+
+ scm_dowinds (SCM_CDR (to), 1 + delta);
+ wind_elt = SCM_CAR (to);
+#if 0
+ if (SCM_INUMP (wind_elt))
+ {
+ scm_cross_dynwind_binding_scope (wind_elt, 0);
+ }
+ else
+#endif
+ {
+ wind_key = SCM_CAR (wind_elt);
+ if ( !(SCM_NIMP (wind_key) && SCM_SYMBOLP (wind_key))
+ && (wind_key != SCM_BOOL_F)
+ && (wind_key != SCM_BOOL_T))
+ scm_apply (wind_key, SCM_EOL, SCM_EOL);
+ }
+ scm_dynwinds = to;
+ }
+ else
+ {
+ SCM from;
+ SCM wind_elt;
+ SCM wind_key;
+
+ from = SCM_CDR (SCM_CAR (scm_dynwinds));
+ wind_elt = SCM_CAR (scm_dynwinds);
+ scm_dynwinds = SCM_CDR (scm_dynwinds);
+#if 0
+ if (SCM_INUMP (wind_elt))
+ {
+ scm_cross_dynwind_binding_scope (wind_elt, 0);
+ }
+ else
+#endif
+ {
+ wind_key = SCM_CAR (wind_elt);
+ if ( !(SCM_NIMP (wind_key) && SCM_SYMBOLP (wind_key))
+ && (wind_key != SCM_BOOL_F)
+ && (wind_key != SCM_BOOL_T))
+ scm_apply (from, SCM_EOL, SCM_EOL);
+ }
+ delta--;
+ goto tail; /* scm_dowinds(to, delta-1); */
+ }
+}
+
+
+#ifdef __STDC__
+void
+scm_init_dynwind (void)
+#else
+void
+scm_init_dynwind ()
+#endif
+{
+#include "dynwind.x"
+}
+