This PR replaces `Array.feraseIdx` and `Array.insertAt` with
`Array.eraseIdx` and `Array.insertIdx`, both of which take a `Nat`
argument and a tactic-provided proof that it is in bounds. We also have
`eraseIdxIfInBounds` and `insertIdxIfInBounds` which are noops if the
index is out of bounds. We also provide a `Fin` valued version of
`Array.findIdx?`. Together, these quite ergonomically improve the array
indexing safety at a number of places in the compiler/elaborator.
This PR changes the signature of `Array.get` to take a Nat and a proof,
rather than a `Fin`, for consistency with the rest of the (planned)
Array API. Note that because of bootstrapping issues we can't provide
`get_elem_tactic` as an autoparameter for the proof. As users will
mostly use the `xs[i]` notation provided by `GetElem`, this hopefully
isn't a problem.
We may restore `Fin` based versions, either here or downstream, as
needed, but they won't be the "main" functions.
---------
Co-authored-by: David Thrane Christiansen <david@davidchristiansen.dk>
I made a few choices so far that can probably be discussed:
- got rid of `modn` on `UInt`, nobody seems to use it apart from the
definition of `shift` which can use normal `mod`
- removed the previous defeq optimized definition of `USize.size` in
favor for a normal one. The motivation was to allow `OfNat` to work
which doesn't seem to be necessary anymore afaict.
- Minimized uses of `.val`, should we maybe mark it deprecated?
- Mostly got rid of `.val` in basically all theorems as the proper next
level of API would now be `.toBitVec`. We could probably re-prove them
but it would be more annoying given the change of definition.
- Did not yet redefine `log2` in terms of `BitVec` as this would require
a `log2` in `BitVec` as well, do we want this?
- I added a couple of theorems around the relation of `<` on `UInt` and
`Nat`. These were previously not needed because defeq was used all over
the place to save us. I did not yet generalize these to all types as I
wasn't sure if they are the appropriate lemma that we want to have.
When `discharge?` failed, the `usedSimps` was being restored, but the
cache wasn't. This bug was exposed by issue #3710.
This PR makes the following changes:
- We restore the `cache` at `discharge?`. We use `SMap` to ensure the
operation is efficient.
- We don't need the field `dischargeDepth` anymore at `Simp.Result`.
- `UsedSimps` should use `PHashMap` since it is not used linearly.
closes#3710
---------
Co-authored-by: Mario Carneiro <di.gama@gmail.com>
This makes changes to the `GetElem` class so that it does not lead to
unnecessary overhead in container like `RBMap`.
The changes are to:
1. Make `getElem?` and `getElem!` part of the `GetElem` class so they
can be overridden in instances.
2. Introduce a `LawfulGetElem` class that contains correctness theorems
for `getElem?` and `getElem!` using the original definitions.
3. Reorganize definitions (e.g, by moving `GetElem` out of
`Init.Prelude`) so that the `GetElem` changes are feasible.
4. Provide `LawfulGetElem` instances to complement all existing
`GetElem` instances in Lean core.
To reduce the size of the PR, this doesn't do the work of providing new
`GetElem` instances for `RBMap`, `HashMap` etc. That will be done in a
separate PR (#3688) that depends on this.
---------
Co-authored-by: Mac Malone <tydeu@hatpress.net>
[Before](https://github.com/leanprover/lean4/files/14772220/oi.pdf) and
[after](https://github.com/leanprover/lean4/files/14772226/oi2.pdf).
This gets `ByteArray`, `String.Extra`, `ToString.Macro` and `RCases` out
of the imports of `omega`. I'd hoped to get `Array.Subarray` too, but
it's tangled up in the list literal syntax. Further progress could come
from make `split` use available `Decidable` instances, so we could pull
out `Classical` (and possibly some of `PropLemmas`).
- Removes the public definitions `Array.eraseIdxAux` and
`Array.eraseIdxSzAux` which were implementation details.
- Motivation: `Array.eraseIdxAux` and `Array.eraseIdxSzAux` were clearly
not intended to remain public, but simply making them private would make
it inconvenient to unfold them when writing proofs in Std.
- Adds documentation comments to the public `Array.eraseIdx`-related
definitions which remain.
- Removes `Array.eraseIdx'` which was just `Array.feraseIdx` wrapped in
a subtype and adds `Array.size_feraseIdx` to prove the subtype property
as a standalone theorem.
Co-Authored-By: Daniel Windham <daniel@atlascomputing.org>
