From 2488429444c2740a075a1f13217ca1838f11026f Mon Sep 17 00:00:00 2001 From: Arnaud Bailly Date: Fri, 17 Oct 2025 22:24:04 +0200 Subject: feat: can desugar expressions --- lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'lambda-calcul/haskell/src/Minilang/Lambda') diff --git a/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs b/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs index 28da47f..37834d3 100644 --- a/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs +++ b/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs @@ -11,6 +11,8 @@ import Data.Void (Void) import Text.Megaparsec (Parsec, between, empty, errorBundlePretty, manyTill, notFollowedBy, optional, parse, try) import Text.Megaparsec.Char (alphaNumChar, char, letterChar, space1, string, symbolChar) import qualified Text.Megaparsec.Char.Lexer as L +import Minilang.Lambda.Eval (Term) +import qualified Minilang.Lambda.Eval as Eval type Parser = Parsec Void Text @@ -20,6 +22,20 @@ data ParseError = ParseError Text data AST = Sym Text | Abs [Text] AST | App AST AST [AST] deriving (Eq, Show) +desugar :: AST -> Term +desugar = \case + Sym sym -> Eval.Var sym + Abs bound body -> + foldr + Eval.Lam + (desugar body) + bound + App x y rest -> + foldl + (\acc a -> Eval.App acc (desugar a)) + (Eval.App (desugar x) (desugar y)) + rest + pretty :: AST -> Text pretty = \case Sym sym -> sym -- cgit v1.2.3