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 introduces ranges that are polymorphic, in contrast to the
existing `Std.Range` which only supports natural numbers.
Breakdown of core changes:
* `Lean.Parser.Basic`: Modified the number parser (`Lean.Parser.Basic`)
so that it will only consider a *single* dot to be part of a decimal
number. `1..` will no longer be parsed as `1.` followed by `.`, but as
`1` followed by `..`.
* The test `ellipsisProjIssue` ensures that `#check Nat.add ...succ`
produces a syntax error. After introducing the new range notation (see
below), it returns a different (less nice) error message. I updated the
test to reflect the new error message. (The error message will become
nicer as soon as a delaborator for the ranges is implemented. This is
out of scope for this PR.)
Breakdown of standard library changes:
Modified modules: `Init.Data.Range.Polymorphic` (added),
`Init.Data.Iterators`, `Std.Data.Iterators`
* Introduced the type `Std.PRange` that is parameterized over the type
in which the range operates and the shapes of the lower and upper bound.
* Introduced a new notation for ranges. Examples for this notation are:
`1...*`, `1...=3`, `1...<3`, `1<...=2`, `*...=3`.
* Defined lots of typeclasses for different capabilities of ranges,
depending on their shape and underlying type.
* Introduced `Iter(M).size`.
* Introduced the `Iter(M).stepSize n` combinator, which iterates over an
iterator with the given step size `n`. It will drop `n - 1` values
between every value it emits.
* Replaced `LawfulPureIterator` with a new and better typeclass
`LawfulDeterministicIterator`.
* Simplified some lemma statements in the iterator library such as
`IterM.toList_eq_match`, which unnecessarily matched over a `Subtype`,
hindering rewrites due to type dependencies.
Reasons for the concrete choice of notation:
* `lean4-cli` uses `...`-based notation for the `Cmd` notation and it
clashes with `...a` range notation.
* test `2461` fails when using two-dot-based notation because of the
existing `{ a.. }` notation.
This PR moves parts of the iterator library from `Std` to `Init`. The
reason is that the polymorphic range API must be in `Init` and it
depends on the iterators.
This PR extends `Std.Channel` to provide a full sync and async API, as
well as unbounded, zero sized and bounded channels.
A few notes on the implementation:
- the bounded channel is inspired by [Go channels on
steroids](https://docs.google.com/document/d/1yIAYmbvL3JxOKOjuCyon7JhW4cSv1wy5hC0ApeGMV9s/pub)
though currently doesn't do any of the lock-free optimizations
- @mhuisi convinced me that having a non-closable channel may be a good
idea as this alleviates the need for error handling which is very
annoying when working with `Task`. This does complicate the API a little
bit and I'm not quite sure whether this is a choice we want users to
give. An alternative to this would be to just write `send!` that panics
on sending to a closed channel (receiving from a closed channel is not
an error), this is for example the behavior that golang goes with.
This PR adds the Lean.RArray data structure.
This data structure is equivalent to `Fin n → α` or `Array α`, but
optimized for a fast kernel-reduction `get` operation.
It is not suitable as a general-purpose data structure. The primary
intended use case is the “denote” function of a typical proof by
reflection proof, where only the `get` operation is necessary, and where
using `List.get` unnecessarily slows down proofs with more than a
hand-full of atomic expressions.
There is no well-formedness invariant attached to this data structure,
to keep it concise; it's semantics is given through `RArray.get`. In
that way one can also view an `RArray` as a decision tree implementing
`Nat → α`.
In #6068 this data structure is used in `simp_arith`.
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.
This is a quite substantial tactic.
It also includes the infamour `NatCast` typeclass (which I've equipped
with a module-doc). I wasn't at all sure where that should live, so it
is currently randomly in `Lean/Elan/Tactic/NatCast.lean`: presumably if
we're doing this it will go somewhere in `Init`.
---------
Co-authored-by: Leonardo de Moura <leomoura@amazon.com>
This upstreams NatCast and IntCast alone independent of norm_cast in
#3322.
This will allow more efficiently upstreaming parts of Std.Data.Int
relevant for omega.
---------
Co-authored-by: Scott Morrison <scott.morrison@gmail.com>
For many data structures having an ordering is necessary. This one adds the `Ord` type class and a deriving handler for it. The ordering is based on order of constructors followed by lexicographical ordering within a constructor.
