This function makes recursive parsers possible.
| i1 : p = futureParser q o1 = p o1 : Parser | 
| i2 : m = p : charAnalyzer o2 = m o2 : FunctionClosure | 
| i3 : q = constParser "abc" o3 = q o3 : Parser | 
| i4 : m "abc" o4 = abc | 
-- ../../../../Macaulay2/packages/Parsing.m2:58 futureParser = parserSymbol -> new Parser from (c -> (value parserSymbol) c)