Replacing swipl‐win - SWI-Prolog/packages-xpce GitHub Wiki

swipl-win has two implementations: one using the Win32 GDI and one using Qt for MacOS and Linux. The Win32 version is getting outdated and the Qt version is a heavy dependency. This sub-project will replace both by an XPCE on SDL+Cairo based embedded terminal.

Design

This project adds a class terminal_image, similar to text_image that provides the basic terminal emulation as an XPCE subclass of graphical. Outline

Use the Windows swipl-win code that implements a two-dimensional terminal with savelines and ANSI escape code handling.
- Wrap the code into class terminal_image, using XPCE's core infrastructure.
- Allow a Prolog thread to act as "client"
  - On non-Windows system, use a PTY for the interface. This way we can reuse the editline command line editor. Also shell/0,1 and friends work out-of-the-box.

Tasks

Implement terminal_image
- Basic terminal rendering
- Map events to terminal actions
- Implement client interaction using POSIX pseudo terminal (PTY)
- How to deal with Windows?
- Implement ANSI terminal handling
  - Basic sequences
  - Bold and underline
  - The 16 ANSI colors
  - 256 color scheme
  - Direct color
Implement a Prolog library to create a fully functional terminal
- Wrap into class epilog
  - Add scrolling
  - Connect to a Prolog thread
  - Add menu
  - Allow multiple terminals (split horizontal/vertical)
  - Proper history handling
  - Deal with thread-local Prolog flags.
Allow using Epilog as main console, such that we can use this as "App"/GUI application
- Add new executable (swipl-win) that starts Epilog
- Run initialization commands in the Epilog environment.

Bugs/issues

Do we need/want shell job control?
cls/0 often leads to assertion error
Handle \e[<n>@ to insert <n> spaces at the current location. Needed for libedit insert.
less quit does not properly clean screen
top display top is garbage.
Trackpad scrolling seems broken.