lean4-htt/tests/elab/string_termination.lean
Garmelon 08eb78a5b2
chore: switch to new test/bench suite (#12590)
This PR sets up the new integrated test/bench suite. It then migrates
all benchmarks and some related tests to the new suite. There's also
some documentation and some linting.

For now, a lot of the old tests are left alone so this PR doesn't become
even larger than it already is. Eventually, all tests should be migrated
to the new suite though so there isn't a confusing mix of two systems.
2026-02-25 13:51:53 +00:00

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Text

module
-- Test that termination proofs for stepping through a string with `next` and `prev` works.
def isConsonant (i : String.Pos str) : Bool :=
match i.get! with
| 'a' | 'e' | 'i' | 'o' | 'u' => false
| 'y' =>
if h : i = str.startPos then true
else !isConsonant (i.prev h)
| _ => true
termination_by i.down
def measure₁ (word : String) : Nat :=
let rec aux (pos : String.Pos word) (inVowel : Bool) (count : Nat) : Nat :=
match h : pos.next? with
| some next =>
if !isConsonant pos then
aux next true count
else if inVowel then
aux next false (count + 1)
else
aux next false count
| none => count
termination_by pos
aux word.startPos false 0
def measure₂ (word : String) : Nat :=
let rec aux (pos : String.Pos word) (inVowel : Bool) (count : Nat) : Nat :=
if h : pos = word.endPos then count
else
let next := pos.next h
if !isConsonant pos then
aux next true count
else if inVowel then
aux next false (count + 1)
else
aux next false count
termination_by pos
aux word.startPos false 0