Replacing swipl‐win

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 The Win32 version is getting outdated and the Qt version is a heavy dependency.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
  • Provide swipl-win substitude using swipl -Depilog
  • 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
  • Support mouse events
• shell(top) does not work properly yet.
• Trackpad scrolling seems broken.
• Double-width characters such as emoji are not handled property.