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/* Copyright 2009
* Kaz Kylheku <kkylheku@gmail.com>
* Vancouver, Canada
* All rights reserved.
*
* BSD License:
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
typedef union uw_frame uw_frame_t;
typedef enum uw_frtype uw_frtype_t;
enum uw_frtype { UW_BLOCK, UW_ENV };
struct uw_common {
uw_frame_t *up;
uw_frtype_t type;
};
struct uw_block {
uw_frame_t *up;
uw_frtype_t type;
obj_t *tag;
obj_t *result;
jmp_buf jb;
};
struct uw_dynamic_env {
uw_frame_t *up;
uw_frtype_t type;
obj_t *func_bindings;
};
union uw_frame {
struct uw_common uw;
struct uw_block bl;
struct uw_dynamic_env ev;
};
void uw_init(void);
void uw_push_block(uw_frame_t *, obj_t *tag);
void uw_push_env(uw_frame_t *);
obj_t *uw_get_func(obj_t *sym);
obj_t *uw_set_func(obj_t *sym, obj_t *value);
obj_t *uw_block_return(obj_t *tag, obj_t *result);
void uw_pop_frame(uw_frame_t *);
#define uw_block_begin(TAG, RESULTVAR) \
obj_t *RESULTVAR = nil; \
{ \
uw_frame_t uw_blk; \
uw_push_block(&uw_blk, TAG); \
if (setjmp(uw_blk.bl.jb)) { \
RESULTVAR = uw_blk.bl.result; \
} else {
#define uw_block_end \
} \
uw_pop_frame(&uw_blk); \
}
#define uw_env_begin \
{ \
uw_frame_t uw_env; \
uw_push_env(&uw_env)
#define uw_env_end \
uw_pop_frame(&uw_env); \
}
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