/* Copyright (C) 1995,1996,1998 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, Inc., 59 Temple Place, Suite 330, * Boston, MA 02111-1307 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 #include "_scm.h" #include "eval.h" #include "alist.h" #include "fluids.h" #include "genio.h" #include "smob.h" #include "dynwind.h" /* {Dynamic wind} Things that can be on the wind list: (enter-proc . leave-proc) dynamic-wind (tag . jmpbuf) catch (tag . lazy-catch) lazy-catch tag is either a symbol or a boolean ((fluid ...) . (value ...)) with-fluids */ SCM_PROC(s_dynamic_wind, "dynamic-wind", 3, 0, 0, scm_dynamic_wind); SCM scm_dynamic_wind (thunk1, thunk2, thunk3) SCM thunk1; SCM thunk2; SCM thunk3; { 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; } /* The implementation of a C-callable dynamic-wind, * scm_internal_dynamic_wind, requires packaging of C pointers in a * smob. Objects of this type are pushed onto the dynwind chain. */ typedef struct guardsmem { scm_guard_t before; scm_guard_t after; void *data; } guardsmem; #define SCM_GUARDSMEM(obj) ((guardsmem *) SCM_CDR (obj)) #define SCM_BEFORE_GUARD(obj) (SCM_GUARDSMEM (obj)->before) #define SCM_AFTER_GUARD(obj) (SCM_GUARDSMEM (obj)->after) #define SCM_GUARD_DATA(obj) (SCM_GUARDSMEM (obj)->data) #define SCM_GUARDSP(obj) (SCM_CAR (obj) == tc16_guards) static long tc16_guards; static scm_sizet freeguards (SCM guards) { scm_must_free ((char *) SCM_CDR (guards)); return sizeof (guardsmem); } static int printguards (SCM exp, SCM port, scm_print_state *pstate) { scm_puts ("#', port); return 1; } static scm_smobfuns guardsmob = { 0, freeguards, printguards, 0 }; SCM scm_internal_dynamic_wind (scm_guard_t before, scm_inner_t inner, scm_guard_t after, void *inner_data, void *guard_data) { SCM guards, ans; guardsmem *g; before (guard_data); SCM_NEWCELL (guards); SCM_DEFER_INTS; g = (guardsmem *) scm_must_malloc (sizeof (*g), "guards"); g->before = before; g->after = after; g->data = guard_data; SCM_SETCDR (guards, g); SCM_SETCAR (guards, tc16_guards); SCM_ALLOW_INTS; scm_dynwinds = scm_acons (guards, SCM_BOOL_F, scm_dynwinds); ans = inner (inner_data); scm_dynwinds = SCM_CDR (scm_dynwinds); after (guard_data); return ans; } #ifdef GUILE_DEBUG SCM_PROC (s_wind_chain, "wind-chain", 0, 0, 0, scm_wind_chain); SCM scm_wind_chain () { return scm_dynwinds; } #endif void scm_dowinds (to, delta) SCM to; long delta; { 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)) { if (SCM_NIMP (wind_key) && SCM_CONSP (wind_key)) scm_swap_fluids (wind_key, SCM_CDR (wind_elt)); else if (SCM_NIMP (wind_key) && SCM_GUARDSP (wind_key)) SCM_BEFORE_GUARD (wind_key) (SCM_GUARD_DATA (wind_key)); else 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)) { if (SCM_NIMP (wind_key) && SCM_CONSP (wind_key)) scm_swap_fluids_reverse (wind_key, from); else if (SCM_NIMP (wind_key) && SCM_GUARDSP (wind_key)) SCM_AFTER_GUARD (wind_key) (SCM_GUARD_DATA (wind_key)); else scm_apply (from, SCM_EOL, SCM_EOL); } } delta--; goto tail; /* scm_dowinds(to, delta-1); */ } } void scm_init_dynwind () { tc16_guards = scm_newsmob (&guardsmob); #include "dynwind.x" }