ujihisa-rubykaigi2017-lt-vim.md

How to develop CRuby easily with Vim

Tatsuhiro Ujihisa github.com/ujihisa

@ujm

>(._. )<

• Develop CRuby with Vim
• Hard to structure things you should know for 5min talk

-> FAQ style 11 questions and answers

Q0. I'm stuck

Play some games

• https://github.com/rbtnn/mario.vim
• https://github.com/johngrib/vim-game-code-break

Q1. Indentation?

Q. Indentation? (1/8)

"CRuby indentations look weird!" - A Rubyist Vimmer

static VALUE
rb_str_casecmp(VALUE str1, VALUE str2)
{
    VALUE s = rb_check_string_type(str2);
    if (NIL_P(s)) {
>-return Qnil;
    }
    return str_casecmp(str1, s);
}

Q. Indentation? (2/8)

Indent 4 spaces for C with tabs for eight-space indentation (emacs default)

according to ruby/doc/contributing.rdoc

For CRuby buffers, do this:

Q. Indentation? (3/8)

in your ~/.vimrc

" Same as default
set cindent
set tabstop=8
set noexpandtab
" Different to the default
set shiftwidth=4 " it was 8
set softtabstop=4 " it was 0

^ works for first file

set shiftwidth=4 softtabstop=4 is equivalent

Q. Indentation? (4/8)

"works for first file" ??

Common mistake 1:

:set is a buffer-local option. Don't :set directly at the top level.

Q. Indentation? (5/8)

in your ~/.vimrc

autocmd FileType c set shiftwidth=4
autocmd FileType c set softtabstop=4

^ works, but not reloadable

Q. Indentation? (6/8)

"works, but not reloadable" ??

Common mistake 2

autocmd FileType c set shiftwidth=4
autocmd FileType c set softtabstop=4

• :autocmd adds an event every
• When you reload this file it registers an additional event again

Q. Indentation? (7/8)

augroup ujihisa-cruby
  autocmd!
  autocmd FileType c set shiftwidth=4
  autocmd FileType c set softtabstop=4
augroup END

Q. Indentation? (8/8)

Or

• Just install github.com/mrkn/vim-cruby
  • new filetype: cruby (instead of c)
  • This also has ruby idiom (e.g. VALUE) for highlight and completion

Q2. jump from ruby method to c?

Q. jump from ruby method to c? (1/)

e.g.

'a'.upcase

'a'.method(:upcase).
  source_location #=> nil

Q. jump from ruby method to c? (2/)

• ri? rdoc?
  • ri has filename info (not visible)
  • no linenum
• ruby-doc.org can show the implementation
  • e.g. https://ruby-doc.org/core-2.4.1/String.html#method-i-upcase
  • how???

Q. jump from ruby method to c? (3/)

CRuby defines C function with rb_define_method

// string.c
rb_define_method(
  rb_cSymbol, "upcase", sym_upcase, -1);

Q. jump from ruby method to c? (4/)

install this vim plugin

https://github.com/ujihisa/cruby-defs.vim

(to be released during RubyKaigi)

* nontrivial but possible.
* manual index
* rdoc or ri (mystery)

• Q. ruby completion
  • (not a cruby dev question)
  • use language server and fix rcodetools

cont'd to pdf slides