lean4-htt/tests/lean/test_extern.lean
Scott Morrison d4dca3baac
feat: test_extern command (#2970)
This adds a `test_extern` command.

Usage:
```
import Lean.Util.TestExtern

test_extern Nat.add 17 37
```

This:
* Checks that the head symbol has an `@[extern]` attribute.
* Writes down `t == t'`, where `t` is the term provided, and `t'` is the
reference implementation (specifically, `t` with the head symbol
unfolded).
* Tries to reduce this to `true`, and complains if this fails.

Note that the type of the term must have a `BEq` instance for this to
work: there's a self-explanatory error message if it isn't available.
2023-12-12 23:33:05 +00:00

9 lines
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Text

import Lean.Util.TestExtern
instance : BEq ByteArray where
beq x y := x.data == y.data
test_extern Nat.add 12 37
test_extern 4 + 5
test_extern ByteArray.copySlice ⟨#[1,2,3]⟩ 1 ⟨#[4, 5, 6, 7, 8, 9, 10, 11, 12, 13]⟩ 0 6