[Haskell-cafe] parsec: parserFail & multiple error messages

silly8888 silly8888 at gmail.com
Wed Aug 8 21:24:31 CEST 2012

I am trying to create a parsec parser that parses an integer and then
checks if that integer has the right size. If not, it generates an
I tried the following:

import Text.Parsec
import Text.Parsec.String

integer :: Parser Int
integer  = do s <- many1 digit
              let n = read s
              if n > 65535 then
                  parserFail "integer overflow"
                  return n

The problem is that when I try this

parse integer "" "70000"

I get the following error:

Left (line 1, column 6):
unexpected end of input
expecting digit
integer overflow

ie there are three error messages but I only want the last one. Is
there something I can do about this?

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