Comment between continuation lines in F77 breaks lexer

[dorchard]

Example:

      SUBROUTINE lex
      IMPLICIT NONE
      INTEGER X, Y,
c break
     &   ZZ
      
      END

Remove the comment and the problem goes away.

[gridaphobe]

https://github.com/camfort/fortran-src/pull/58 addresses this in the Fortran77Legacy mode, though it throws the comments away.

I know GHC has done some work on preserving comments that can appear anywhere in the source code. That might be a good place to look if you want a parse<->print isomorphism including arbitrary comments.