diff options
Diffstat (limited to 'lambda-calcul/haskell/src/Minilang/Lambda/Unify.hs')
| -rw-r--r-- | lambda-calcul/haskell/src/Minilang/Lambda/Unify.hs | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/lambda-calcul/haskell/src/Minilang/Lambda/Unify.hs b/lambda-calcul/haskell/src/Minilang/Lambda/Unify.hs index ad06552..df66113 100644 --- a/lambda-calcul/haskell/src/Minilang/Lambda/Unify.hs +++ b/lambda-calcul/haskell/src/Minilang/Lambda/Unify.hs @@ -1,4 +1,5 @@ -- ported from https://www.cs.cornell.edu/courses/cs3110/2011sp/Lectures/lec26-type-inference/type-inference.htm +{-# LANGUAGE LambdaCase #-} module Minilang.Lambda.Unify where import Data.Text (Text) @@ -12,6 +13,16 @@ data Type infixr 5 :-> +pretty :: Type -> Text +pretty = \case + TyVar x -> x + f :-> g -> + let left = case f of + TyVar _ -> pretty f + _ -> "(" <> pretty f <> ")" + right = pretty g + in left <> " -> " <> right + -- invariant: no identifier on the left hand-side can appear in -- an earlier term in the list, ie. the list is in "dependency order" -- and forms a DAG. |