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Diffstat (limited to 'libguile/dynwind.c')
-rw-r--r-- | libguile/dynwind.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/libguile/dynwind.c b/libguile/dynwind.c new file mode 100644 index 000000000..b80a00c76 --- /dev/null +++ b/libguile/dynwind.c @@ -0,0 +1,148 @@ +/* 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" +} + |