Add character set helpers

src_v2/parser/parser_internals.nim

@@ -101,6 +101,10 @@ proc ch*(expectedChar: char): parserFnT {.inline.} =
 
 let anyCh* = ch(AllChars)
 let digit* = ch(Digits)
+let letter* = ch(Letters)
+let space* = ch(' ')
+let whitespace* = ch(Whitespace)
+let newline* = ch(Newlines)
 
 proc str*(expectedString: string): parserFnT {.inline.} =
   ## Creates parser function with `expectedString`