libguile/fluids.h

   1 /* classes: h_files */
   2
   3 #ifndef SCM_FLUIDS_H
   4 #define SCM_FLUIDS_H
   5
   6 /* Copyright (C) 1996,2000,2001, 2006, 2008, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public License
  10  * as published by the Free Software Foundation; either version 3 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  21  * 02110-1301 USA
  22  */
  23
  24 \f
  25
  26 #include "libguile/__scm.h"
  27 #include "libguile/root.h"
  28 #include "libguile/vectors.h"
  29
  30
  31 /* Fluids.
  32
  33    Fluids are objects of a certain type that can hold one SCM value per
  34    dynamic state. That is, modifications to this value are only visible
  35    to code that executes with the same dynamic state as the modifying
  36    code. When a new dynamic state is constructed, it inherits the
  37    values from its parent. Because each thread executes with its own
  38    dynamic state, you can use fluids for thread local storage.
  39
  40    Each fluid is identified by a small integer. This integer is used to
  41    index a vector that holds the values of all fluids. A dynamic state
  42    consists of this vector, wrapped in an object so that the vector can
  43    grow.
  44  */
  45
  46 #define SCM_FLUID_P(x)          (SCM_HAS_TYP7 (x, scm_tc7_fluid))
  47 #ifdef BUILDING_LIBGUILE
  48 #define SCM_I_FLUID_NUM(x)        ((size_t)(SCM_CELL_WORD_0 (x) >> 8))
  49 #define SCM_I_FLUID_DEFAULT(x)    (SCM_CELL_OBJECT_1 (x))
  50 #endif
  51
  52 SCM_API SCM scm_make_fluid (void);
  53 SCM_API SCM scm_make_fluid_with_default (SCM dflt);
  54 SCM_API SCM scm_make_unbound_fluid (void);
  55 SCM_API int scm_is_fluid (SCM obj);
  56 SCM_API SCM scm_fluid_p (SCM fl);
  57 SCM_API SCM scm_fluid_ref (SCM fluid);
  58 SCM_API SCM scm_fluid_set_x (SCM fluid, SCM value);
  59 SCM_API SCM scm_fluid_unset_x (SCM fluid);
  60 SCM_API SCM scm_fluid_bound_p (SCM fluid);
  61
  62 SCM_INTERNAL void scm_swap_fluid (SCM fluid, SCM value_box, SCM dynamic_state);
  63
  64 SCM_API SCM scm_c_with_fluids (SCM fluids, SCM vals,
  65                                SCM (*cproc)(void *), void *cdata);
  66 SCM_API SCM scm_c_with_fluid (SCM fluid, SCM val,
  67                               SCM (*cproc)(void *), void *cdata);
  68 SCM_API SCM scm_with_fluids (SCM fluids, SCM vals, SCM thunk);
  69 SCM_API SCM scm_with_fluid (SCM fluid, SCM val, SCM thunk);
  70
  71 SCM_API void scm_dynwind_fluid (SCM fluid, SCM value);
  72
  73 #ifdef BUILDING_LIBGUILE
  74 #define SCM_I_DYNAMIC_STATE_P(x) (SCM_HAS_TYP7 (x, scm_tc7_dynamic_state))
  75 #define SCM_I_DYNAMIC_STATE_FLUIDS(x)        SCM_PACK (SCM_CELL_WORD_1 (x))
  76 #endif
  77
  78 SCM_API SCM scm_make_dynamic_state (SCM parent);
  79 SCM_API SCM scm_dynamic_state_p (SCM obj);
  80 SCM_API int scm_is_dynamic_state (SCM obj);
  81 SCM_API SCM scm_current_dynamic_state (void);
  82 SCM_API SCM scm_set_current_dynamic_state (SCM state);
  83 SCM_API void scm_dynwind_current_dynamic_state (SCM state);
  84 SCM_API void *scm_c_with_dynamic_state (SCM state,
  85                                         void *(*func)(void *), void *data);
  86 SCM_API SCM scm_with_dynamic_state (SCM state, SCM proc);
  87
  88 SCM_INTERNAL SCM scm_i_make_initial_dynamic_state (void);
  89
  90 SCM_INTERNAL void scm_i_fluid_print (SCM exp, SCM port, scm_print_state *pstate);
  91 SCM_INTERNAL void scm_i_dynamic_state_print (SCM exp, SCM port, scm_print_state *pstate);
  92 SCM_INTERNAL void scm_init_fluids (void);
  93
  94 #endif  /* SCM_FLUIDS_H */
  95
  96 /*
  97   Local Variables:
  98   c-file-style: "gnu"
  99   End:
 100 */