implement notcurses-dialog ("colloquy")

[dankamongmen]

the bearded class will recognize "dialog" as an ncurses input tool, distributed with ncurses (see https://invisible-island.net/ncurses/ncurses.faq.html#related_programs). we ought do a prettier one, and ship it as notcurses-dialog.

[dankamongmen]

       Dialog is a program that will let you present a variety of questions or
       display messages using dialog boxes from a shell script.   These  types
       of  dialog  boxes  are implemented (though not all are necessarily com‐
       piled into dialog):

              buildlist, calendar, checklist, dselect, editbox, form, fselect,
              gauge, infobox, inputbox, inputmenu, menu, mixedform,
              mixedgauge, msgbox (message), passwordbox, passwordform, pause,
              prgbox, programbox, progressbox, radiolist, rangebox, tailbox,
              tailboxbg, textbox, timebox, treeview, and yesno (yes/no).

that's quite a few widgets, heh

[dankamongmen]

just as an idea, we could do this in Rust (see #101 )

[dankamongmen]

alright, after looking at whiptail, some notes:

• its only placement option is --topleft. gag me. provide at least --vert {top, middle, bottom} and --horiz {left, middle, right}. maybe provide absolute yx. maybe provide offsets.
• by default, we will (a) not use the alternate screen and (b) use only the necessary part of the screen, and (c) be semi-transparent
• it requires providing a height and width, gaaaaaaaag, and if you provide unsuitable ones, it generates garbage, GAG. by default we will make the minimum box necessary for the provided options. we will allow the user to overrule this, and hard fail if they give bad arguments.
• inputbox...we'll need a lower-level object to implement this, perhaps integrating readline
• i think we ought provide a runtime or time/date, so that machines don't look locked up (make this optional, obviously)
• scrollbars

dialog has a lot more stuff: calendar, menu, treeview, tailbox, and more...

[dankamongmen]

i like dialog's --file argument, allowing you to provide all other arguments via file. implement that with a unified parser against the CLI, and it's a righteous dub. it looks like both dialog and whiptail accept 0 for the size arguments to produce a minimal one, which is nice, but i'd rather it just be the default.

dialog when provided --colors interprets a 'Zcode' allowing inline style specifiers. it seems reasonable enough, i guess. unnecessary, though?

--no-items is an interesting option. i think we already do that, though, in our selector widget?

[dankamongmen]

i'm thinking it's maybe a good idea to hew to dialog's CLI, and be a drop-in replacement, unless there's a really good reason not to.

[dankamongmen]

this tool will be named colloquy, and it will (mostly) follow the dialog CLI. it will be written in rust. all the UI widgets will be written in the C notcurses core. it may only use rust dependencies which are available in debian.

• add a CMake option regarding rust, default to true
• build rust bindings as part of make
• add debian packaging for rust bindings, build-deps
• get cratespace for colloquy
• build colloquy as part of make
• implement dialog-like CLI in rust

[dankamongmen]

Last open issue for 1.3.0! It's a big fucker, though!