IRB with Ripper
I replaced lexical analyzer with Ripper. It's important for supporting new syntax.
I explain what I did.
Replace with Ripper¶
I talked with @matz (Yukihiro Matsumoto) about it and I decided to use mirb of mruby as a reference.
The mirb uses compile error messages and token information such as token type and lex_state for that whether or not inputted code continues(and PROMPT_N). I used RubyVM::InstructionSequence#compile and Ripper for the same action.
ref. IRB#each_top_level_statement, IRB#lex and IRB#check_code_block
Continue(PROMPT_N), literal type(PROMPT_S), nesting level(%NNi)¶
IRB needs statuses of code snippets. @nobu (Nobuyoshi Nakada) implemented it as Ripper's features at irb-ripper branch on GitHub.
I implemented by pure Ruby because I heard what @nobu (Nobuyoshi Nakada) thinks pure Ruby implementation for it. I think that it's the best way for that Ripper keeps simple.
ref. IRB#process_continue, IRB#process_nesting_level, IRB#check_string_literal and IRB#process_literal_type
Erase --irb_debug option¶
Because this is just for pure Ruby lexical analyzer.