This PR adjusts the experimental module system to make `private` the
default visibility modifier in `module`s, introducing `public` as a new
modifier instead. `public section` can be used to revert the default for
an entire section, though this is more intended to ease gradual adoption
of the new semantics such as in `Init` (and soon `Std`) where they
should be replaced by a future decl-by-decl re-review of visibilities.
This PR introduces polymorphic slices in their most basic form. They
come with a notation similar to the new range notation. `Subarray` is
now also a slice and can produce an iterator now. It is intended to
migrate more operations of `Subarray` to the `Slice` wrapper type to
make them available for slices of other types, too.
The PR also moves the `filterMap` combinators into `Init` because they
are used internally to implement iterators on array slices.
This PR adjusts the experimental module system to not export the bodies
of `def`s unless opted out by the new attribute `@[expose]` on the `def`
or on a surrounding `section`.
---------
Co-authored-by: Markus Himmel <markus@lean-fro.org>
This PR changes the signature of `Array.swap`, so it takes `Nat`
arguments with tactic provided bounds checking. It also renames
`Array.swap!` to `Array.swapIfInBounds`.
Adds the ability to show a diff when `guard_msgs` fails, using the
histogram diff algorithm pioneered in jgit. This algorithm tends to
produce more user-friendly diffs, but it can be quadratic in the worst
case. Empirically, the quadratic case of this implementation doesn't
seem to be slow enough to matter for messages smaller than hundreds of
megabytes, but if it's ever a problem, we can mitigate it the same way
jgit does by falling back to Myers diff.
See lean/run/guard_msgs.lean in the tests directory for some examples of
its output.
