Singleton class definition do not introduce its own class variable scope
in CRuby/JRuby. So should mruby.
```
module Mod1
class << Object.new
C = 1
@@cv = 1
p Module.nesting, # => [#<Class:#<Object:0x55cb16e60a50>>, Mod1]
constants, # => [:C]
class_variables, # => []
Mod1.class_variables # => [:@@cv]
end
end
```
The binary sizes (gems are only `mruby-bin-mruby`) are reduced slightly in
my environment than before the introduction of new specifiers/modifiers
(5116789a) with this change.
------------+-------------------+-------------------+--------
BINARY | BEFORE (5116789a) | AFTER (This PR) | RATIO
------------+-------------------+-------------------+--------
mruby | 593416 bytes | 593208 bytes | -0.04%
libmruby.a | 769048 bytes | 767264 bytes | -0.23%
------------+-------------------+-------------------+--------
BTW, I accidentally changed `tasks/toolchains/visualcpp.rake` at #4613,
so I put it back.
Fix the following example:
Object.const_set :A, Module.new{const_set :B, Class.new}
ab = A::B.to_s
p ab #=> "A::B" # Good
ab[0] = "x"
p A::B.to_s #=> "x::B" # Bad
Functions to add prototypes to headers:
* mrb_ary_splice()
* mrb_notimplement()
* mrb_vformat()
* mrb_cstr_to_dbl()
* mrb_cstr_to_inum()
Functions to be made `static` (`MRB_API` was not needed):
* mrb_mod_module_function()
* mrb_obj_hash()
* mrb_str_len_to_inum()
Functions to remove `MRB_API` from definitions (referenced from within `libmruby`):
* mrb_mod_cv_defined()
* mrb_mod_cv_get()
* mrb_f_send()
* return `void` instead of `mrb_bool'.
* non zero return value from `func` breaks the loop.
* no longer remove items on negative return value from `func`.
Unlike method definition, constant reference should start from
`MRB_PROC_TARGET_CLASS(ci->proc)`, not `ci->target_class`.
In addition, `MRB_PROC_TARGET_CLASS(ci->proc)` is always set.
Instead of `irep` links, we added a `upper` link to `struct RProc`.
To make a space for the `upper` link, we moved `target_class` reference.
If a `Proc` does not have `env`, `target_class` is saved in an `union`
shared with `env` (if a `Proc` has env, you can tell it by `MRB_PROC_ENV_P()).
Otherwise `target_class` is referenced from `env->c`. We removed links
in `env` as well.
This change removes 2 members from `mrb_irep` struct, thus saving 2
words per method/proc/block. This also fixes potential memory leaks
due to the circular references caused by a link from `mrb_irep`.
Instead of `irep -> proc` chain, we use `irep -> irep` chain to
avoid GC bugs like #3804. We added `target_class` reference to
`mrb_irep` struct. That means one more word consumption per `irep`.
KOBAYASHI Shuji