Ghost elements

[dethe]

There are times we want to select the place an block will be, to fill in later with a specific block. This can be tied with keyboard controls for instance to indent a block or set of blocks with a placeholder for a new contex wrapper.

[CelticMinstrel]

The context placeholder is probably by far the most useful case for this.

[dethe]

Super useful for expressions too. Right now if you want to replace a number with a math expression it's super annoying to remove the number, insert the math, then put the number back in. This way you could wrap the number with a ghost expression, then find the math block you wanted to replace the ghost.

There's a use case for steps too: I want a step here, so mark it with a ghost while I find the block to put there.

[dethe]

There's another interaction possible too. Right now we don't allow blocks to be dropped sockets that already have expression blocks, but we could prompt "replace, wrap, ignore".

[CelticMinstrel]

Ah, yeah, I see what you mean for expressions.