This commit simplifies warnings for hash keys duplication and when clause duplication,
based on the discussion of https://bugs.ruby-lang.org/issues/20331.
Warnings are reported only when strings are same to ohters.
- Introduce `rb_parser_ary_t` structure to partly eliminate RArray from parse.y
- In this patch, `parser_params->tokens` and `parser_params->ast->node_buffer->tokens` are now `rb_parser_ary_t *`
- Instead, `ast_node_all_tokens()` internally creates a Ruby Array object from the `rb_parser_ary_t`
- Also, delete `rb_ast_tokens()` and `rb_ast_set_tokens()` in node.c
- Implement `rb_parser_str_escape()`
- This is a port of the `rb_str_escape()` function in string.c
- `rb_parser_str_escape()` does not depend on `VALUE` (RString)
- Instead, it uses `rb_parser_stirng_t *`
- This function works when --dump=y option passed
- Because WIP of the universal parser, similar functions like `rb_parser_tokens_free()` exist in both node.c and parse.y. Refactoring them may be needed in some way in the future
- Although we considered redesigning the structure: `ast->node_buffer->tokens` into `ast->tokens`, we leave it as it is because `rb_ast_t` is an imemo. (We will address it in the future)
String nodes holds ruby string object on `VALUE nd_lit`.
This commit changes it to `struct rb_parser_string *string`
to reduce dependency on ruby object.
Sometimes these strings are concatenated with other string
therefore string concatenate functions are needed.
NODE_ARGS, NODE_ARYPTN, NODE_FNDPTN manage memory of their
structure by imemo tmpbuf Object.
However rb_ast_struct has reference to NODE. Then these
memory can be freed directly when rb_ast_struct is freed.
This commit reduces parser's dependency on CRuby functions.
Introduce Universal Parser mode for the parser.
This commit includes these changes:
* Introduce `UNIVERSAL_PARSER` macro. All of CRuby related functions
are passed via `struct rb_parser_config_struct` when this macro is enabled.
* Add CI task with 'cppflags=-DUNIVERSAL_PARSER' for ubuntu.
