Thanks for that! I was mainly thinking that by returning functions, one can compose for more complex editor operations, more functions at once, and even simplif

Thanks for that! I was mainly thinking that by returning functions, one can compose for more complex editor operations, more functions at once, and even simplify them (if they cancel each other). Off course this is not currently possible, unless the returned functions are some kind of AST tree, and there is something that can optimize them at runtime (dynamic programming?)... Probably overkill.... For example deleteBlock might delete 10 lines, and if there is better composability, instead of returning undo to insert 10 individual lines, it can be merged as one operation with 10 lines, basically by having rules, if you have production like "insertLine * insertLine * insertLine * insertLine" - you can make this as "insertLines[lines collected]" - but that's beyond the discussion. All this just to avoid making insertBlock/deleteBlock special, but reuse insertLine/deleteLine.... lost my thought already - too late in the morning....