From e1fbd95e4eab218952d8b72f672e35c771291dfd Mon Sep 17 00:00:00 2001
From: rockofox <ofelix@pm.me>
Date: Sat, 7 Dec 2024 14:27:57 +0100
Subject: [PATCH] Make parser properly parse function definitions with 0
 parameters (fix #11)

---
 lib/Parser.hs       | 2 +-
 tests/ParserSpec.hs | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/Parser.hs b/lib/Parser.hs
index b15e551..b26d917 100644
--- a/lib/Parser.hs
+++ b/lib/Parser.hs
@@ -260,7 +260,7 @@ defArg = try structLit <|> var <|> parens listPattern <|> array <|> placeholder
 funcDef :: Parser Expr
 funcDef = do
     name <- identifier <|> gravis <?> "function name"
-    args <- some defArg <?> "function arguments"
+    args <- many defArg <?> "function arguments"
     symbol "="
     FuncDef name args <$> expr <?> "function body"
 
diff --git a/tests/ParserSpec.hs b/tests/ParserSpec.hs
index c9a053c..99da369 100644
--- a/tests/ParserSpec.hs
+++ b/tests/ParserSpec.hs
@@ -21,6 +21,15 @@ parserCompilerFlags = initCompilerFlags{needsMain = False}
 
 spec :: Spec
 spec = do
+    describe "Function definitions" $ do
+        it "Should parse a simple function" $
+            parseProgram "add a b = a + b" parserCompilerFlags
+                `shouldBe` Right
+                    (Program [FuncDef{name = "add", args = [Var "a" anyPosition, Var "b" anyPosition], body = Add (Var "a" anyPosition) (Var "b" anyPosition)}])
+        it "Should prase a function with 0 parameters" $
+            parseProgram "thunk = 1" parserCompilerFlags
+                `shouldBe` Right
+                    (Program [FuncDef{name = "thunk", args = [], body = IntLit 1}])
     describe "compareTypes" $ do
         it "Should be true for exact matches" $
             property $