syntax tree. That's what I'll used for entered dimensions, and
algebraic constraints and such. Needs to be extended to handle
stuff like points and entities, but I think that it can be.
[git-p4: depot-paths = "//depot/solvespace/": change = 1669]
the plane basis vectors) work, easy. Tweak the text window a bit,
for cosmetics, and start to add the symbolic expression code.
[git-p4: depot-paths = "//depot/solvespace/": change = 1667]