Hi Anis, well a history system and a constraint solving mechanism are kind of separate things.

A constraint solver can be used to edit shapes, but once a shape is edited it is up to a history system to recalculate operations to cause that edit to update things downstream.

So history and constraints are not quite the same things - it is possible for example to have a constraint mechanism just as a method to edit a curve, without anything to do with history. Similarly it is possible to have a history mechanism that does not use constraints, instead it just applies any kind of edits (control point editing, etc...) through a sequence of operations to make a modified result.

I am interested in adding some constraint functions in the future though too, but similarly it will require quite a lot of work and a lot of UI design so I'm not certain when it would take place. But that is largely a separate area of work from history actually.

- Michael