[scotty79]

Is that the reason for two different type annotation signifiers? That some day I might want to extend the language with something?

It sounds a bit like if every C function (including hello world) had to have empty asm block because someone might need it some day.

[soegaard]

The operator `expr :~ annot` simply attaches the static information to the expression.

The operator `expr :: annot` will at runtime insert a check that the expression satisfies the annotation.

[scotty79]

What if I want both behaviors at the same time? Have some static information attached and also do a runtime check?