## Summary
This following is a behavior from CRuby 1.8.7 to 3.1.0.
```console
% ruby -ve "p ['a', 'b', 'c']*''"
ruby 1.8.7 (2013-12-22 patchlevel 375) [i686-darwin13.0.2]
"abc"
% ruby -ve "p ['a', 'b', 'c']*''"
ruby 3.1.0p0 (2021-12-25 revision fb4df44d16) [x86_64-darwin19]
"abc"
```
### Before (mruby 3.0.0)
mruby unexpectedly gives the TypeError.
```ruby
['a', 'b', 'c']*'' #=> String cannot be converted to Integer (TypeError)
```
### After
This PR makes mruby behave compatible with CRuby.
```ruby
['a', 'b', 'c']*'' #=> 'abc'
```
As far as I checked, the behavior is unspecified when `Array#*`'s argument
is not an instance of Integer class in X 3017 : 2013 (ISO/IEC 30170 : 2012).
## Additional Information
I noticed this difference by the following idiom when writing ASCII art code
using Ruby.
```ruby
%w(foo bar baz)*''
```
e.g. TRICK (https://github.com/tric)
To be also able to build mruby without presym in the future. However,
`MRB_QSYM` has been removed and changed as follows:
### Example
| Type | Symbol | Previous Style | New Style |
|---------------------------|--------|------------------|----------------|
| Operator | & | MRB_QSYM(and) | MRB_OPSYM(and) |
| Class Variable | @@foo | MRB_QSYM(00_foo) | MRB_CVSYM(foo) |
| Instance Variable | @foo | MRB_QSYM(0_foo) | MRB_IVSYM(foo) |
| Method with Bang | foo! | MRB_QSYM(foo_b) | MRB_SYM_B(foo) |
| Method with Question mark | foo? | MRB_QSYM(foo_p) | MRB_SYM_Q(foo) |
| Mmethod with Equal | foo= | MRB_QSYM(foo_e) | MRB_SYM_E(foo) |
This change makes it possible to define, for example, `MRB_IVSYM(foo)` as
`mrb_intern_lit(mrb, "@" "foo")`, which is useful if we support building
without presym in the future.
The `mrb_get_argv()` function will now return `const mrb_value *`.
This is because it is difficult for the caller to check if it is a splat argument (array object) and to write-barrier if necessary.
The "a"/"*" specifier of the `mrb_get_args()` function will now return `const mrb_value *`.
This is because it is difficult for the caller to check if it is an array object and write-barrier if necessary.
And it requires calling `mrb_ary_modify()` on the unmodified array object, which is also difficult (this is similar to #5087).
- Integrate `Fixnum` and `Integer`
- Remove `Integral`
- `int / int -> int`
- Replace `mrb_fixnum()` to `mrb_int()`
- Replace `mrb_fixnum_value()` to `mrb_int_value()`.
- Use `mrb_integer_p()` instead of `mrb_fixnum_p()`
- `MRB_WITHOUT_FLOAT` => `MRB_NO_FLOAT`
- `MRB_USE_FLOAT` => `MRB_USE_FLOAT32`
The former is to use `USE_XXX` naming convention. The latter is to make
sure `float` is 32bit float and not floating point number in general.
When the array is very big, the simpler `mrb_write_barrier` causes
calling `gc_mark_children` for big arrays repeatedly. That would hinder
performance very badly.
When the array is very big, the simpler `mrb_write_barrier` causes
calling `gc_mark_children` for big arrays repeatedly. That would hinder
performance very badly.
`mrb_get_arg1()` raises `ArgumentError` if the method does not receive one
argument.
And replaces all `mrb_get_args(mrb, "o", &arg)` by the new function.
Formerly, `__send__(*args)` modified `args` with `Array#shift`.
This bug affects optcarrot.
This changeset avoids the array destruction by using
`args = args[1, len-1]`.
When removing elements from an array, it is possible to avoid creating
an empty array.
Before this patch:
```c
mrb_ary_splice(mrb, ary, head, len, mrb_ary_new(mrb));
```
After this patch:
```c
mrb_ary_splice(mrb, ary, head, len, mrb_undef_value());
```
#### Before this patch:
```
$ mruby -e '[].each(1){}' #=> no error
```
#### After this patch:
```
$ mruby -e '[].each(1){}' #=> ArgumentError: wrong number of arguments
```
Yukihiro "Matz" Matsumoto