I have managed to get a minimally functional gui using Qt5, which was not an easy feat since the tutorials available at this time are geared toward Qt4. Things like what must be #included have changed, and also a line must be added to the .pro file: QT += widgets. Once I waded through all that, plus just general confusion due to lack of experience, I was able to use the tutorials to create functioning examples with qtcreator, the Qt IDE, which I could then study and use to figure out how to integrate my existing c++ code. I also found out that in order to have dual output to a gui and a console window, for instance to use cout, you have to compile and run the code from a console, not from within qtcreator. This involves generating a makefile with qmake and then running make. If you run qmake -project like it says to do in the tutorials, you have to add the QT line mentioned above in order for make to succeed. Apparently the version of qmake that comes with Qt5 still creates a Qt4 .pro file? ... read more
Most likely gui will be implemented using qtcreator. Have settled on initial rough layout. Next software upload will most likely be a minimally functional gui. Supposedly qtcreator enables straightforward compiling for Windows and Linux binaries, so will try to have each available on next update.
The input parser is now functional. Even though only two commands are currently working, movlw and movwf, I am going to start work on the gui. When I have a basically functional gui, I will start implementing more commands.