core: ParseCharE

src/Parser/ParserState.md

@@ -216,6 +216,19 @@ parseChar : Has ParserState fs => (predicate : Char -> Bool) -> (err : Char -> e
   -> Eff fs (ParseCharResult e)
 parseChar predicate err = send $ ParseChar predicate err
 
+||| Wrapper for parseChar that folds the error message into effect stack with the
+||| provided callback
+export
+parseCharE : Has ParserState fs => Has (Except e) fs => 
+  (predicate : Char -> Bool) -> (err : Char -> e) -> (eof : Lazy e)
+  -> Eff fs Char
+parseCharE predicate err eof = do
+  result <- parseChar predicate id
+  case result of 
+    GotChar char => pure char
+    GotError x => throw $ err x
+    EndOfInput => throw eof
+
 ||| "Parse" the end of input, returning `True` if the parser state is currently
 ||| at the end of the input
 export