diff options
| author | Chloe Brown <chloe.brown.00@outlook.com> | 2023-04-15 16:16:35 +0100 |
|---|---|---|
| committer | Chloe Brown <chloe.brown.00@outlook.com> | 2023-04-15 16:16:35 +0100 |
| commit | 5f83999f483e241158706522a35364ba32f7f203 (patch) | |
| tree | 539d16ca0ed14ecfe1d495ec2deeaaf8f284501c /src/Core/Thinning.idr | |
| parent | ed9beabb1e5f867bad0c0693f36cd0ffc0d5d96c (diff) | |
Define Term substitution.
Diffstat (limited to 'src/Core/Thinning.idr')
| -rw-r--r-- | src/Core/Thinning.idr | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/src/Core/Thinning.idr b/src/Core/Thinning.idr index dc4efcb..a2500e9 100644 --- a/src/Core/Thinning.idr +++ b/src/Core/Thinning.idr @@ -68,3 +68,18 @@ export wkn : Fin m -> m `Thins` n -> Fin n wkn i IsId = i wkn i (IsThinner thin) = wkn' i thin + +-- Composition ----------------------------------------------------------------- + +comp : Thinner m n -> Thinner k m -> Thinner k n +comp IsBase thin2 = IsDrop thin2 +comp (IsDrop thin1) thin2 = IsDrop (comp thin1 thin2) +comp (IsKeep thin1) IsBase = IsDrop thin1 +comp (IsKeep thin1) (IsDrop thin2) = IsDrop (comp thin1 thin2) +comp (IsKeep thin1) (IsKeep thin2) = IsKeep (comp thin1 thin2) + +export +(.) : m `Thins` n -> k `Thins` m -> k `Thins` n +IsId . thin2 = thin2 +IsThinner thin1 . IsId = IsThinner thin1 +IsThinner thin1 . IsThinner thin2 = IsThinner (comp thin1 thin2) |