OBJ lookup_variable_value(OBJ name,OBJ env)
{
OBJ find;
while(!nullp(env))
{
find = assq(name,env_frame(env));
if(!nullp(find))
return cdr(find);
env = env_base(env);
}
if(find == OBJ_NULL)
fprintf(stderr,"undefined variable:%s\n",obj_symbol_data(name));
return OBJ_NULL;
}
static OBJ analyze_variable_cell(OBJ variable,OBJ env,int macro,OBJ params,OBJ macro_expand_env)
{
OBJ tmp;
OBJ ret;
if(macro)
{
tmp = assq(variable,params);
if(nullp(tmp)) /* if variable isn't params of macro,lookup it at macro_define_env */
ret = lookup_variable_cell(variable,env);
else /* otherwise lookup variable at macro_expand_env...ie,current env */
ret = lookup_variable_cell(cdr(tmp),macro_expand_env);
}
else
ret = lookup_variable_cell(variable, env);
return ret;
}
OBJ define(OBJ name,OBJ value,OBJ env)
{
OBJ find;
find = assq(name,env_frame(env));
if(find == OBJ_NULL)
{
find = cons(name,value);
env_frame(env) = cons(find,env_frame(env));
}
else
{
cdr(find) = value;
}
return find;
}
static long longfield(char *name,LISP alist)
{LISP value,key = rintern(name);
if NULLP(value = assq(key,alist))
return(0);
return(get_c_long(cdr(value)));}
static char *strfield(char *name,LISP alist)
{LISP value,key = rintern(name);
if NULLP(value = assq(key,alist))
return("");
return(get_c_string(cdr(value)));}
