This PR adds support for pretty printing using generalized field
notation (dot notation) for private definitions on public types. It also
modifies dot notation elaboration to resolve names after removing the
private prefix, which enables using dot notation for private definitions
on private imported types.
It won't pretty print with dot notation for definitions on inaccessible
private types from other modules.
Closes#7297
This PR migrates usages of `Std.Range` to the new polymorphic ranges.
This PR unfortunately increases the transitive imports for
frequently-used parts of `Init` because the ranges now rely on iterators
in order to provide their functionality for types other than `Nat`.
However, iteration over ranges in compiled code is as efficient as
before in the examples I checked. This is because of a special
`IteratorLoop` implementation provided in the PR for this purpose.
There were two issues that were uncovered during migration:
* In `IndPredBelow.lean`, migrating the last remaining range causes
`compilerTest1.lean` to break. I have minimized the issue and came to
the conclusion it's a compiler bug. Therefore, I have not replaced said
old range usage yet (see #9186).
* In `BRecOn.lean`, we are publicly importing the ranges. Making this
import private should theoretically work, but there seems to be a
problem with the module system, causing the build to panic later in
`Init.Data.Grind.Poly` (see #9185).
* In `FuzzyMatching.lean`, inlining fails with the new ranges, which
would have led to significant slowdown. Therefore, I have not migrated
this file either.
This PR modifies the pretty printer so that dot notation is used for
class parent projections. Previously, dot notation was never used for
classes.
We still need to modify dot notation to take the method resolution order
into account when collapsing parent projections.
This PR avoids runtime array bounds checks in places where it can
trivially be done at compile time.
None of these changes are of particular consequence: I mostly wanted to
learn how much we do this, and what the obstacles are to doing it less.
For structure projections, the pretty printer assumed that the
expression was type correct. Now it checks that the object being
projected is of the correct type. Such terms appear in type mismatch
errors.
Also, fixes and improves `#print` for structures. The types of
projections now use MessageData (so are now hoverable), and the type of
`self` is now the correct type.
Closes#4670
On
[Zulip](https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/Notation.20in.20namespace.20not.20showing.20in.20pp/near/437016468),
Peter Nelson reported that notations that could be pretty printed with
generalized field notation did not pretty print using the intended
notation.
This PR makes it so that app unexpanders are considered before
generalized field notation. The complexity before was that we wanted to
do parent projection collapse, and since we did the collapse before
pretty printing that argument, it meant it wasn't possible to do app
unexpanders when there was a field notation candidate. The new solution
is to collapse parent projections only when actually considering field
notation, which can be done because we can safely strip off projection
syntax in an expression-directed way.
Sets the default value to `pp.fieldNotation.generalized` to `true`.
Updates tests, and fixes some minor flaws in the implementation of the
generalized field notation pretty printer.
Now generalized field notation won't be used for any function that has a
`motive` argument. This is intended to prevent recursors from pretty
printing using it as (1) recursors are more like control flow structures
than actual functions and (2) generalized field notation tends to cause
elaboration problems for recursors.
Note: be sure functions that have an `@[app_unexpander]` use
`@[pp_nodot]` if applicable. For example, `List.toArray` needs
`@[pp_nodot]` to ensure the unexpander prints it using `#[...]`
notation.
Refactors app delaborator, merging in the projection delaborator, to
support pretty printing with generalized field notation.
Renames option `pp.structureProjections` to `pp.fieldNotation` and adds
sub-option `pp.fieldNotation.generalized` to enable/disable generalized
field notation. Adds `@[pp_nodot]` attribute to permanently disable
using field notation for a given declaration.
For now, the default value of `pp.fieldNotation.generalized` is false
since we need a stage0 update to add `@[pp_nodot]` to some core
definitions (such as `List.toArray`) before updating the tests.
[Zulip
discussion](https://leanprover.zulipchat.com/#narrow/stream/270676-lean4/topic/.60pp.2EgeneralizedFieldNotation.60/near/425856054)
