Choose syntax and implement destructuring existentials with pure components, following !400
It'd be nice to support something like iDestruct "H" as "∃[%x HP]" on "H": ∃ x, P (where the ∃[ipat ipat] syntax is a strawman), mapping that introduction pattern to iExistsDestruct. The killer feature is support for nested existentials, which require multiple iDestruct calls today.
In discussion on !400 (merged), I and @tchajed considered supporting that with pattern [%x HP], but that pattern is already mapped to iAndDestruct, and unlike in Coq the two methods are very different.
Steps:
- bikeshed a syntax
- any other discussion on the specification, if needed
- implement this.