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-rw-r--r--lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs31
1 files changed, 27 insertions, 4 deletions
diff --git a/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs b/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs
index da590ad..545536d 100644
--- a/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs
+++ b/lambda-calcul/haskell/src/Minilang/Lambda/Parser.hs
@@ -13,15 +13,38 @@ type Parser = Parsec Void Text
data ParseError = ParseError Text
deriving (Eq, Show)
-data AST = Sym Text
+data AST = Sym Text | Abs Text AST
deriving (Eq, Show)
parse :: Text -> Either ParseError AST
parse =
- first (ParseError . pack . errorBundlePretty) . Text.Megaparsec.parse symbol ""
+ first (ParseError . pack . errorBundlePretty) . Text.Megaparsec.parse ast ""
-symbol :: Parser AST
-symbol = Sym . pack <$> identifier
+ast :: Parser AST
+ast = try lambda <|> try sym
+
+lambda :: Parser AST
+lambda =
+ between
+ lpar
+ rpar
+ ( do
+ lexeme "lam"
+ binding <- pack <$> between lpar rpar identifier
+ Abs binding <$> ast
+ )
+
+lpar :: Parser Text
+lpar = symbol "("
+
+rpar :: Parser Text
+rpar = symbol ")"
+
+symbol :: Text -> Parser Text
+symbol = L.symbol spaceConsumer
+
+sym :: Parser AST
+sym = Sym . pack <$> identifier
identifier :: Parser String
identifier =