lean4-htt/tests/bench/nat_repr.lean
Paul Reichert 98e4b2882f
refactor: migrate to new ranges (#8841)
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.
2025-07-07 12:41:53 +00:00

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def main : List String → IO Unit
| [n] => do
let mut s := 0
for i in *...n.toNat! do
for j in *...i do
s := s + j.repr.length
IO.println s
| _ => throw $ IO.userError "give upper bound"