From f8dfbfc1604aea626a6502b9f6d06ea1299a0cdb Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Tue, 6 Sep 2022 12:50:21 +0100
Subject: Split statement parsers to get better error reporting

Also prevents duplicated parsers for var.
---
 src/Parser.hs | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/Parser.hs b/src/Parser.hs
index 2817208..5ee6de9 100644
--- a/src/Parser.hs
+++ b/src/Parser.hs
@@ -86,9 +86,10 @@ fdef ident priv anon pos = do
   body <-
     braces $
       many $
-        try (grVar False) <|> do
-          x <- statement
+        do
+          x <- fStatement
           pure $ [x]
+          <|> grVar True
   return $ Func ident args rtyp (concat $ body) priv anon pos
 
 function :: Bool -> Parser Expr
@@ -102,7 +103,6 @@ function priv = do
 varWithValue :: Bool -> Parser Expr
 varWithValue priv = do
   (ident, typ, _, pos) <- arg
-  -- FIXME: this error hint is not being used
   reservedOp "=" <?> "assignation"
   value <- expr
   return $ Var ident typ value priv pos
@@ -175,11 +175,15 @@ exprStmt = do
   reservedOp ";"
   return $ e
 
+-- statements that appear in functions
+fStatement :: Parser Expr
+fStatement = try exprStmt <|> var True <|> return'
+
+-- top level statement
 statement :: Parser Expr
-statement = do
-  try exprStmt
-    <|> var False
-    <|> return'
+statement =
+  try exprStmt <|> try (privateDf var)
+    <|> return' -- this will raise an error
 
 module' :: Parser Expr
 module' = do
@@ -193,11 +197,10 @@ program = do
   m <- module'
   n <-
     many $
-      try (privateDfn grVar) <|> do
-        x <-
-          try (privateDf function) <|> try (privateDf var)
-            <|> statement
+      do
+        x <- try (privateDf function) <|> statement
         pure $ [x]
+        <|> privateDfn grVar
   return $ [m] ++ (concat $ n)
 
 parse :: Parser [Expr]
-- 
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