It uses BER number compression of delta of instruction positions and line
numbers. BER compression is a variable length number representation.
* `mrb_debug_line_ary`: array of line numbers represented in `uint16_t`.
`[lineno, lineno, ...]`
* `mrb_debug_line_flat_map`: array of `mrb_irep_debug_info_line`, which
is `struct {uint32_t pos; uint16_t lineno}`, for each line.
* `mrb_debug_line_packed_map` [new]: sequence of BER compressed 2
numbers, `pos_delta, lineno_delta`. Deltas are differences from
previous values (starting `0`). `line_entry_counts` represents total
length of a packed map string for this type.
This reverts commit fd10c72319.
I thought it was OK to restrict index value within 1 byte, but in some
cases index value could be 16 bits (2 bytes). I had several ideas to
address the issue, but reverting `fd10c72` is the easiest way. The
biggest reason is `mruby/c` still supports `OP_EXT[123]`, so that they
don't need any additional work.
```console
% for rb in `git ls-files '*/mrblib/*.rb' 'mrblib'`; do ruby30 -cw $rb > /dev/null; done
mrbgems/mruby-array-ext/mrblib/array.rb:389: warning: assigned but unused variable - ary
mrbgems/mruby-array-ext/mrblib/array.rb:663: warning: assigned but unused variable - len
mrbgems/mruby-hash-ext/mrblib/hash.rb:119: warning: possibly useless use of a variable in void context
mrbgems/mruby-hash-ext/mrblib/hash.rb:259: warning: assigned but unused variable - keys
mrbgems/mruby-io/mrblib/io.rb:229: warning: literal in condition
mrbgems/mruby-io/mrblib/io.rb:280: warning: literal in condition
mrbgems/mruby-string-ext/mrblib/string.rb:347: warning: assigned but unused variable - len
mrbgems/mruby-toplevel-ext/mrblib/toplevel.rb:2: warning: parentheses after method name is interpreted as an argument list, not a decomposed argument
```
It does not need to hold an anonymous proc for constant search.
Also, this change can be expected to cause an anonymous proc to be GC'd.
This is useful for metaprogramming that makes heavy use of the `class`/`module`/`def` syntax in the `class_eval`/`eval` method.
Example:
- code
```ruby
p ObjectSpace.count_objects
String.class_eval do
def a
end
end
p ObjectSpace.count_objects
String.class_eval do
eval <<~CODE
def b
end
CODE
end
p ObjectSpace.count_objects
```
- result of building mruby-head (d63c0df6b) with `build_config/default.rb`
```
{:TOTAL=>1024, :FREE=>262, :T_PROC=>495, :T_ENV=>61, ...}
{:TOTAL=>1024, :FREE=>259, :T_PROC=>497, :T_ENV=>62, ...}
{:TOTAL=>1024, :FREE=>255, :T_PROC=>500, :T_ENV=>63, ...}
```
- result of building mruby with this patch and `build_config/default.rb`
```
{:TOTAL=>1024, :FREE=>264, :T_PROC=>494, :T_ENV=>60, ...}
{:TOTAL=>1024, :FREE=>262, :T_PROC=>495, :T_ENV=>61, ...}
{:TOTAL=>1024, :FREE=>261, :T_PROC=>496, :T_ENV=>61, ...}
```
Previously the following code did not produce the expected results:
```ruby
bx = binding
block = bx.eval("a = 1; proc { a }")
bx.eval("a = 2")
p block.call # Expect 2 but return 1 due to a bug
```
The previous implementation of `Binding#eval` evaluated the code and then merged the top layer variables.
This patch will parse and expand the variable space before making a call to `eval`.
This means that the call to `Binding#eval` will do the parsing twice.
In addition, the following changes will be made:
- Make `mrb_parser_foreach_top_variable()`, `mrb_binding_extract_proc()` and `mrb_binding_extract_env()` functions private global functions.
- Remove the `posthook` argument from `mrb_exec_irep()`.
The `posthook` argument was introduced to implement the `binding` method.
This patch is unnecessary because it uses a different implementation method.
ref #5362fixed#5491
If no new variable was defined in the `eval` method, the variable was hidden from the nested `eval` method.
```ruby
a = 1
p eval %(b = 2; eval %(a)) # => 1 (good)
p eval %(eval %(a)) # => undefined method 'a' (NoMethodError)
```
This issue has occurred since mruby 3.0.0.
- ` mrb_block_given_p()` -- The name comes from CRuby's `rb_block_given_p ()`
At the same time, it applies to `f_instance_eval()` and `f_class_eval()` of `mruby-eval`.
Yukihiro "Matz" Matsumoto