Git integration via Tig

Tig is an ncurses-based interface for Git

Here's how to show git blame information in Tig:

define-command tig -params .. -docstring "Run tig" %{
	terminal env "EDITOR=kak -c %val{session}" tig %arg{@}
}
define-command tig-blame-here -docstring "Run tig blame on the current line" %{
	tig -C %sh{git rev-parse --show-toplevel} blame -C "+%val{cursor_line}" -- %sh{
		dir="$(git rev-parse --show-toplevel)"
		printf %s "${kak_buffile##$dir/}"
	}
}

To show the history of the selected lines, try this command (inspired by https://github.com/junegunn/gv.vim):

define-command tig-blame-selection -docstring "Run tig -L on the selected lines" %{
	evaluate-commands -draft -save-regs d %{
		execute-keys <a-:>
		set-register d %sh{git rev-parse --show-toplevel}
		tig -C %reg{d} %sh{
			anchor=${kak_selection_desc%,*}
			anchor_line=${anchor%.*}
			cursor=${kak_selection_desc#*,}
			cursor_line=${cursor%.*}
			d=$kak_reg_d
			printf %s "-L$anchor_line,$cursor_line:${kak_buffile##$d/}"
		}
	}
}

For an alternative approach, see https://github.com/mawww/kakoune/wiki/Integrating-Other-CLI-apps#tig