An Editor for Composed Programs (2014)

SDE tools have the grammar of the language being edited built in, which means they know which trees are syntactically valid. Simplifying a little, it seemed to us that MPS had made as good a stab as anyone is likely to manage at moving an SDE tool in the direction of a normal text editor; we wondered if it might be possible to move a normal text editor in the direction of SDE. In other words, we hoped to make an editor with all the tree goodness of SDE tools, but which would feel like a normal text editor.

Source: tratt.net