Add parser result initialiser

src/parser/parser.nim

@@ -109,6 +109,9 @@ proc initParser*(str: string): Parser =
     tokens: newSeq[Token](),
   )
 
+proc initParserResult*(str: string): ParserResult =
+  ParserResult.ok(initParser(str))
+
 func ch*(expectedChars: set[char]): (Parser -> ParserResult) {.inline.} =
   return func(parser: Parser): ParserResult =
     let state = parser.state